2 Volumes Final Proceedings - Washington 1984.pdf - IARC Research

PERMAFROSTFourth International ConferenceFINAL PROCEEDINGSIJuly 17-22, 1983Organized byUniversity of Alaska andNational Academy of SciencesNATIONAL ACADEMY PRESSWashington, D.C. 1984Organizing CommitteeT.L. PdwdG.E. WellerA.J. AlterJ. BartonJ. BrownO.J. Ferrians, Jr,H.O. JahnsJ.R. KielyA.H. LachenbruchR.D. MillerR.D. RegerA.L. WashburnJ . H . ZurnbergeL. DeGoes

NATIONAL ACADEMY PRESS 2101 Constitution Avenue NW Washington, DC 20418The National Research Council was established by the National Academyof Sciences in 1916 to associate the broad community of science andtechnology with the Academy's purposes of furthering knowledge and ofadvising the federal government. The Council operates in accordancewith general policies determined by the Academy under the authority ofits congressional charter of 1863, which establishes the Academy as aprivate, nonprofit, self-governing membership corporation. The Councilhas become the principal operating agency of both the National Academyof Sciences and the National Academy of Engineering in the conduct oftheir services to the government, the public, and the scientific andengineering communities. It is administered jointly by both Academiesand the Institute of Medicine. The National Academy of Engineering andthe Institute of Medicine were established in 1964 and 1970, respectively,under the charter of the National Academy of Sciences.Library of Congress Catalog Card Nmber 85-60050International Standard Book Number 0-309-03533-3Permafrost: Fourth International Conference, Final Proceedings&..,+v I, **-Printed in the UnizSiatc'lf. .. .. . . Sciences to publish thd reports issued by thk Academy &wNational Academy of Engineering, the Institute of Medicine, and theNational Research Council, all operating under the charter granted tothe National Academy of Sciences by the Congress of the United States.. $Wlfi

PrefacePerennially frozen ground, or permafrost, underliesan estimated 20 percent of the land surfaceof the earth. It affects many human activities,causing unique problem in agriculture, mining,water supply, sewage disposal, and constructionof airfields, roads, railroads, urban areas,and oil and gas pipelines. Therefore, understandingof its distribution and behavior is essential.Although the existence of permafrost has beenknown to the inhabitants of Siberia for centuries,not until 1836 did scientists of the Western worldtake seriously the accounts of thick frozen groundexisting under the forests and tundra of northernEurasia. In that year, Alexander Theodor von Middendorfwasured temperatures to a depth of approximately107 m in permafrost in the SharginShaft, an unsucceseful wel dug in Yakutsk for thegovernor of the Russian-Alaskan Trading Company.It was estimated that the permafrost there was 215m thick. For over a century since then, scientistsand engineers in Siberia have been activelystudying permafrost and applying the results oftheir research in the development of the region.Similarly, prospectors and explorers have beenaware of permafrost in northern North Alserica formany years, but not until World War I1 were systematicstudies undertaken by scientists and engineersin the United States and Canada.As a result of the explosive increase in researchinto the scientific and engineering aspectsof frozen ground since the late 1940s in Canada,the United States, the USSR, and, more recently,the People's Republic of China, and Japan, amongother countries, it becam apparent that scientistsand engineers working in the field needed toexchange information on an international level.The First International Conference on Permafrostwas therefore held in the United States at PurdueUniversity in 1963. This relatively small conferencewas extremely successful and yielded a publicationthat is still used throughout the world.In 1973 approximately 400 participants attendedthe Second International Conference on Permafrostin Yakutsk, Siberia, USSR. By that time it hadbecome apparent that a conference should be heldevery 5 years or so, to bring together scientistsand engineers to hear and discuss the latest developmentsin their fields. Thus in 1978 Canadahosted the Third Internatlonal Conference on Permafrostin Edmonton, Alberta, including fieldtrips to northern Canada. Approximately 450 participantsfrom 14 nations attended, and Chinesescientists were present for the first time. Thepublished proceedings of all three of these conferencesare available (see p. 413).In Edmonton it was decided that the UnitedStates would host the fourth conference, and aformal offer was made by the University of Alaska.Subsequently, the Fourth International Conferenceon Permafrost was held at the Universityof Alaska at Fairbanks, July 17-22, 1983. It wasorganized and cosponsored by committees of thePolar Research Board of the National Academy ofSciences and the State of Alaska. Local and extendedfield trips to various parts of the stateand northwestern Canada, to examine permafrostfeatures, were made an integral part of the conference.Approximately 900 people participated in thenumerous activities, and 350 papers and posterdisplays from 25 countries were presented at theconference. Many engineering and scientific disciplineswere represented, including civil andmechanical engineering, soil mechanics, glacialand periglacial geology, geophysics, marine science,climatology, soil science, hydrology, andecology. The formal program consisted of paneldiscussions followed by paper and poster presentations.The panels considered the followingthemes: pipelines, climatic change and geothermalregime, deep foundations and embankments, permafrostterrain and environmental protection, frostheave and ice segregation, and subsea permafrost.A total of 276 contributed papers were publishedin the first volume of the proceedings.Reports of panel and plenary sessions, additionalcontributed papers and abstracts, summaries offield trips, and lists of participants are includedin this second volume.The U.S. Organizing Committee is indebted tothe many sponsors for their financial support, tothe technical and professional organizations whichparticipated in the program, and to the localFairbanks organizers for their efforts, which resultedin a highly successful meeting.iii

AcknowledgmentsWe wish to acknowledge all those who contributedtheir time and resources to the success ofthe conference. The names of all contributingsponsors are llsted on p. vi.Dixie R. Brown, Executive Director, Office ofDevelopment, University of Alaska, and Jay Barton,President, University of Alaska Statewide System,organized the private sector fund raising. Theconference itself was organized by the NationalAcademy of Sciences under a U.S. Organizing Committeeof the Polar Research Board and its Committeeon Permafrost. Members of the U.S. OrganizingCommittee are listed on p. vii. W. Timothy Hushen,Muriel A. Dodd, Ruth Siple, Barbara Valentlno,and Louis DeGoes of the Polar Research Board providedinvaluable administrative assistance in arrangingthe conference and processing manuscriptsfor publication. The Paper Review and PublicationCommittee (see Appendix C), chaired by Robert D.Miller, reviewed more than 300 papers and abstracts.Literally hundreds of reviewers assistedthe Committee; their names are also listed inAppendix C. Louis DeGoes served as secretary toboth the U.S. Organizing Committee and the PaperReview and Publication Committee.Editing of the first proceedings volume wasunder the direction of Robert C. Rooney of the NationalAcademy of Sciences. Roseanne R. Price andChris McShane provided editorial assistance forthe 276 papers published in the first volume. Thestaff of the National Acadeny Press, under the directionof William M. Burns, expeditiously processedmore than 2000 pages of camra-ready mnuscriptfor the two-volume compendium. Throughoutthe publication of both volums, the editorial,graphics and word processing staffs at the ColdRegions Research and Engineering Laboratory assistedin lnany ways, including editing and preparationof the final caera-ready copy of much ofthe present volume. Individuals involved includedMaria Bergstad and Stephen L. Been, editing;Donna B. Harp, Barbara A. Jewel1 and Nancy G.Richardson, word processing; Edward M. Perkins andMatthew H. Pacillo, graphics; and Barbara A. Gaudette,Sandra J. Smith and Donna R. Murphy, compositionand paste-up. Dianne M. Nelson of CRIlELprovided secretarial support for many aspects ofconference organization. The camera-ready copy ofthe Soviet papers was prepared by Mary Ann Barr.Michael Hammond, interpreter, assisted in editingsome of the Soviet contributed papers.The actual organization of the conference wasaccomplished in Alaska by local organizing committees.The Fairbanks activities were under the supervisionof Gunter E. Weller, Vice Chairlnan ofthe U.S. Organizing Comdttee. Dr. Weller's leadershipand foresight were major contributing factorsin the success of the conference. WilliamD. Harrison and William M. Sackinger were thechairmen of the program committee and the localarrangements committee, respectively. They wereably assisted by Kathryn W. Coffer, Cheryl E.Howard and other support staff of the GeophysicalInstitute of the University of Alaska, includingJim Coccia, photographer, and the editorial staffof the Northern Englneer under Carla Helfferich.Numerous local volunteers, who cannot all be listedhere, helped with the preparations. s. RussellStearns, President, Amrican Society of Civil Engineers,presented the keynote address at the conference banquet.The Departrnent of Conferences and Institutesof the University of Alaska provided rmch of theorganizational support for the actual conference.This included all details on pre-registration andhousing arrangements, actual conference registration,and support for laany aspects of the socialand technical activities that took place duringthe week. These efforts were under the directionof John R. Hickey and Nancy Bachner; Elaine Walker,Gary Walker and Sharon Oien played majorroles. Personnel of the Housing Office, includingEric A. Jozwiak and Mark Van Rhyn, were most helpfulin accommodating the hundreds of participantsand their families. Timothy L. Jensen and RonaldU. Monteleone of the AFtA Food Service did an excellentjob in preparing and serving refreshmentsfor the opening session and the barbecue.Several other activities deserve special attention.Editing and publication of the fieldguidebooks were performed by the Alaska Divisionof Geological and Geophysical Surveys, Fairbanks.The ADGGS editorial and support staff includesCheri L. Daniels and Frank L. Larson, PublicationSpecialists; Karen S. Pearson and Ann C. Schell,Cartographers; Marlys J. Stroebele and Roberta A.Mann, Clerk Typists; and student interns DuncanR. Hickmott, Barbara A. Kelly, Terry M. Owen,Kathy M. Smyer and David A. Vogel.A special organizing committee was establishedin Anchorage to provide €or local arrangewritsthere. This committee was chaired by WayneC. Hanson of Dames and Moore, and was ably assistedby numerous volunteers, including so- of thestaff of the University of Alaska's Arctic EnvironmentalInformation and Data Center. 'Ihe WorldAffairs Council hosted a reception prior to therailroad field trip for the Chinese delegation andothers. Finally, the chaimn's office at ArizonaState University was ably assisted throughout theiv

course of the pre- and post-conference activitiesby Frances S. Lunsford, Alice Spears, and Joan F.Bahamonde, who provided secretarial support formany aspects of the conference and the publicationeffort. In addition, James T. Bales, Jr., andGlenn R. Bruck were most helpful in preparation offield maps for the extended field trips; and SusanM. Selkirk, Artist-in-Ftesidence of the Museum ofGeology, provided artistic and cartographic supportfor several publications.The Executive Committee of the U.S. OrganieingCommittee (Troy h. P6wW6, Chairman, Gunter E.Weller, Vice-Chairman, and Jerry Brm) and LouisDeGoes were responsible €or overseeing and organizingthe conference and its publications. B r mand PLd were responsible for organizing and BUpervisingthe preparation of this volume for publication.We again thank all those who conttibutedso much to thie conference and its publications.Troy L. P&€, ChairmanU.S. Organizing CommttteeFourth International Conferenceon PermafrostJerry Brown, ChairmanCommittee on PermafrostPolar Research BoardV

Contributing SponsorsThe following sources contributed financial supportInternational Conference on Permafrost.to the FourthFederal AgenciesArmy Research Off ice National Oceanic & AtmosphericBureau of Land ManagementAdministrationCold Regions Research and National Science FoundationEngineering Laboratory Office of the Federal Inspector (ANGTSForest ServiceOffice of Naval ResearchMinerals Management Service U. S. Department of EnergyNational Aeronautics and Space U. S. Geological SurveyAdministrationState of AlaskaAlaska Council on Science and TechnologyDepartment of Transportation and Public FacilitiesState LegislatureIndustry and PrivateSOH10 Alaska Petroleum CompanyAtlantic Richfield FoundationExxon Production Research and Exxon Company USAJohn KielyBechtel Petroleum, Inc., and Brown and Root (Halliburton)Bechtel Power CorporationCONOCO, IntoChevron USA, Inc.Dames and MooreAlyeska Pipeline Service Company Ebasco Semi ces , Inc.Mapco/North Pole RefiningGetty Oil CompanyAlaska Construction IndustryHarza EngineeringAdvancement Program Nerco Minerals (Resource AssociateDresser Foundationof Alaska)British Petroleum, Ltd. , Inc. Rocky Mountain EnergyMorrison-Knudsen Company, Inc.Schlumberger Well ServicesKodiak-Nabors (Anglo-Energy)Tesoro Petroleum CorporatlonMarathon Oil FoundationConrad Topp EngineeringNorthwest Pipeline Service Company Try&, Nyman, HayesShell Oil CompanyAlaska International ConstructorsUnion Oil of California Foundation Doyon Ltd.Cameron Iron Works, Inc.Shannon and WilsonAlaska Industrial Resources, Inc. R.A. Kreig & Associates, Inc.Phillips PetroleumDWL Engineers3-M Company Fryer, Pressley , ElliottAlfred Jurzykowski Foundation, Inc. Peter Kiewit and SonsNational Geographic SocietyWilliam J. KingLaw Engineering Testing Stutzman Engineering AssociatesR & M ConsultantsUnwen Scheben Korynta HuettlAnaconda Copper Company Arctic Slope Consulting Engineersvi

U.S. Organizing CommitteeTroy L. Pewe (Chairman), Arizona State UniversityGunter E. Weller (Vice-chairman), University of AlaskaAmos J. Alter, Technical Council on Cold Regions Engineering, ASCEJay Barton, University of AlaskaJerry Brown, Cold Regions Research and Engineering LaboratoryOscar J. Ferrians, Jr., U. S. Geological SurveyHans 0. Jahns, Exxon Production Research CompanyJohn R. Kiely Bechtel CorporationArthur H. Lachenbruch, U.S. Geological SurveyRobert D. Miller, Cornell UniversityRichard D. Reger, Alaska Division of Geological and Geophysical SurveysA. Lincoln Washburn, University of WashingtonJames H. Zumberge, University of Southern CaliforniaLouis DeGoes, Fourth International Conference on PermafrostProgram Chairman: William D. Harrison, University of AlaskaPaper Review and Publication Chairman: Robert D. Miller, Cornell UniversityField Trips Chairman: Oscar J. Ferrians, Jr., U.S. Geological SurveyLocal Arrangements Chairman: Wiliam M. Sackinger, University of AlaskaParticipating Technical OrganizationsAlaska Academy of Engineering and ScienceAlaska Council on Science and TechnologyAlaska Oil and Gas AssociationAmerican Association for the Advancement of Science (Arctic Division)American Geophysical Union (Committee on Space Hydrology)American Society of Civil Engineers (Technical Council on Cold RegionsEngineering)American Society of Mechanical Engineers (Low Temperature Heat TransferCommittee)American Meteorological Society (Committee on Polar Meteorology)Cold Regions Research and Engineering LaboratoryComite Arctique InternationalInternational Geographical Union (Periglacial Commission)U.S. Man and the Biosphere Program (MAB, Arctic Directorate)vi i

ContentsOPENING PLENARY SESSION 1REPORTS OF PANEL SESSIONS 13Deep Foundations and Embankments 15IntroductionMorgenstern, N.R.15Placing of Deep Pile Foundations in Permafrost in the USSR 16Vyalov, S. S.Study and Practice on Deep Foundations in Permafrost Areas of China 18Ding JinkangDesign and Performance of Road and Railway Embankments on Permafrost 25Esch, D.C.Design and PerformanceSayles, F.H.Design and ConstructionAmerican PracticeLadanyi , B .of Water-Retaining Embankments in Permafrostof Deep Foundations in Permafrost: North3143Frost Heave and Ice SegregationIntroductionPenner, E.The Principles of Themorheology of Cryogenic SoilsGrechishchev, S.E.Current Developments in China on Frost-Heave Processes in SoilChen Xiaobai51515255Thermally Induced, Regelation:Miller, R. D.Moisture Migration in Frozen SoilsWilliams, P. J.A Qualitative Discussion6164Status of Numerical Models for Heat and Mass Transfer in Frost-Susceptible SoilsBerg, R.L.67viii

Subsea Permafrost 73IntroductionHopkins, -D.M. and P.V. SellmannSubsea Permafrost Distribution on the Alaskan ShelfSellmann, P.V. and D.M. HopkinsA Perspective on the Distribution of Subsea Permafrost on theCanadian Beaufort Continental ShelfBlasco, S.M.Soviet Studies of the Subsea CryolithozoneAre, F.E.73758387Geophysical TechniquesHunter, J.A.M.for Subsea Permafrost Investigations88Subsea Permafrost and Petroleum DevelopmentJahns , H. 0.Geotechnical and Engineering SignificanceHayley , D.W.of Subsea Permafrost9093Pipelines in Northern Regions 97IntroductionFerrians, 0. J. , Jr.Pipelines in the Northern U.S.S.R.Ferrians, 0. J., Jr.Hot-Oil and Chilled-Gas Pipeline InteractionMathews, A. C.Pipeline Thermal ConsiderationsJahns, H. 0.Pipeline Workpads in AlaskaMetz, M.C.with Permafrost9798100101106Performance of the Trans-AlaskaJohnson, E. R.Oil Pipeline109Environmental Protection of Permafrost Terrain 113Introduction and a Case StudyHemming, J.E.Development and Environmental Protection in the Permafrostof the USSR: A ReviewGrave, N. A.Zone113116Regulatory Responsibilities in Permafrost Environments of Alaskafrom the Perspective of a Federal Land ManagerMcVee, C.V. and J.V. Tileston125

XTerrain and Environmental Problems Associated with ExploratoryDrilling, Northern CanadaFrench, H.M.Petroleum Exploration and Protection of the Environment on theNational Petroleum Reserve in AlaskaBrewer, M.C.Terrain Sensitivity and Recovery in Arctic RegionsWebber, P. J.Climate Change and Geothermal RegimeIntroductionJudge, A.and J. PilonStudy of Climate Change in the Permafrost Regions of China -A ReviewCheng Guodong129133135137137139Response of Alaskan Permafrost toOsterkamp, T.E.Climate Change and Other EffectsSmith, M.Climateon Permafrost145153Reconstructions and Future Predictions of the Effects of ClimateChangeGray, J.T.156SOVIET CONTRIBUTIONSinvited Soviet PapersMajor Trends in the Development of Soviet Permafrost ResearchMel'nikov, P.I.Drilling and Operation of Gas Wells in the Presence of NaturalGas HydratesGritsenko, A.I. and Makogon, Yu.F.The Impact of Installations for the Extraction and Transport of Gason Permafrost Conditions in Western Siberia and ComprehensiveEngineering Geology Forecasting of Resultant ChangesZakharov, Yu.F., L.D. Kosukhin, and Ye.M. NanivskiyEngineering Geocryology in the USSR: A ReviewVyalov, S.S.The Construction of Deep Pile Foundations in Permafrost in theUSSR - A SummarySadovskiy, A.V.161163163167173177186

xiContributed Soviet 195 PapersThe Physicochemical Nature of the Formation of Unfrozen Water inFrozen Soils 195Akimov, Yu.P., E.D. Yershov, and V.G. CheveryovEffects of Variations in the Latent Heat of Ice Fusion in Soils onInteraction of Boreholes with Permafrost 200Anisimov, M.A., R.U. Tankayev, and A.D. UlantsevMass Transfer in the Snow Cover of Central YakutiaAre, A.L.204Possible Applications of Foam Cements in Protecting the Environmentin Connection Well with Drilling 20 8Bakshoutov, V.Investigation of Areas of Icing (Naled) Formation and SubsurfaceWater Discharge Under Permafrost Conditions Using SurfaceGeophysicalTechniques 211Boikov, S.A., V.E. Afanasenko, and V.M. TimofeyevPrinciples of Terrain Classification for Pipeline Construction 217Demidjuk, L.M., G.S. Gorskaya, and V.V. SpiridonovOn the Physicochemical Properties of the,Surface of Dispersed Ice(Snow) 22 2Fedoseev, N.F., V.I. Fedoseeva, E.A. NechaevThe Thermal Regime of Permafrost Soils in the USSRGavrilova, M.K,226Laws Governing the Compaction of Thawing Soils Taking DynamicProcesses Effect into231Karlov, V.D. and V.K. InosemtsevA Theory of Desiccation of Unconsolidated Rocks in Areas withNegative Temperatures 236Komarov, I.A.Thermal Interaction Between Pipelines and the EnvironmentKrivoshein, B.L.24 2Deformation of Freezing, Thawing, and Frozen Rocks 248Lebedenko, Yu.P., L.V. Shevchenko, O.A. Kondakova, Yu.V.Kuleshov, V.D. Yershov, A.V. Brushkov, and V.S. PetrovMigration of Elements in Water in Taiga-Permafrost LandscapesMakarov, V. N.253

xi iInvestigation of the Deformation of Clayey Soils Resulting fromFrost Heaving and ThawingFoundations Due to Loading 259Malyshev, M.A., V.V. Fursov, and M.V. BaluyuraArtificial Ice Masses in Arctic Seas 264Melnikov, P.I. , K.F. Voitkovsky, R.M. Kamensky, andI.P. KonstantinovApplication of Microwave Energy for Accelerating Excavation inFrozen Soil 2 68Misnyck, Yu.M., O.B. Shonin, N.I. Ryabets, and V. S. PetrovCryogeothermal Problems in the Study of the Arctic Ocean 27 3Neizvestnov, Ya.V., V.A. Soloviev, and G.D. GinsburgInvestigations into the Compaction of Thawing Earth Materials 278Pakhomova, G.M.The Thermal Regime of Thermokarst Lakes in Central Yakutia 282Pavlov, A.V. and F.E. ArePrediction of Construction Characteristics of Sluiced MaterialsUsed in Foundations Under Permafrost Conditions and inSevere Climates 286Poleshuk, V. L.Analog Methods for Determining Long-Term Deformability of PermafrostMaterials 29 0Roman, L.T.Resistivity Logging of Frozen RocksSnegi rev, A.M.29 5Stress-Strain Condition and the Assessment of Slope Stability inAreas of Complex Geological Structure Under Various TemperatureRegimes 300Ukhov, S.B., E.P. Gulko, V.P. Merzlyakov, and P.B. KotovA New Technique for Determining the Static Fatigue Limit of FrozenGround 306Vrachev, V.V., I.N. Ivaschenko, and E.P. ShusherinaPermafrost Beneath the Arctic SeasZhigarev, L. A.31 1Problems of Geocryology (Preface and Abstracts) 315OTHER CONTRIBUTIONS (Abstracts and Papers) 32 1Electrical Thawing of Frozen SoilsJumikis A.R.33 3

xiiiCLOSING PLENARY SESSIONAPPENDIX A: FIELD TRIPSAPPENDIX B: FORMAL PROGRAM.APPENDIX C: COMMITTEES AND REVIEWERSAPPENDIX D: PARTICIPATIONAUTHOR INDEX339347369379385411AVAILABLE PUBLICATIONS OF INTERNATIONAL PERMAFROSTCONFERENCES 413

PERMAFROSTFourth International ConferenceFINAL PROCEEDINGS

Opening Plenary SessionMonday, July 18, 1983TROY L. P d - ~ Ladies and gentlemen: Welcome tothe formal sessions of the Fourth InternationalConference on Permafrost. I am Troy Ph6, Chairumnof the Organizing Committee for the Conference.We, the Organizing Committee, eubcommittees,staff, and many others, are pleased to haveyou here and invite you to participate in and attendthe panel, paper, and poster sessions, thelocal field trips, the extended field trips, andsocial events. Today, I will first introduce ourfront-table dignitaries and then offer a few wordsabout permafrost research history. This will befollowed by words of welcome from Alaskan and internationalparticipants.It is my pleasure to introduce the persons atthe front table. At my far right [not visible inphotograph] is Dr. Jerry Brown of the Cold RegionsResearch and Engineering Laboratory, who is representingthe Polar Research Board of the UnitedStates National Academy of Sciences and is theChairman of the Permafrost Committee of the PolarResearch Board. He is also a member of our OrganizingCommittee. Next to Dr. Brown is Mr. Li Yusheng,Vice Principal of the Chinese Academy ofRailway Sciences of che Ministry of Railways fromBeijing, China. He 1s the co-leader of the delegationfrom the People's Republic of China. Nextis Dr. Jay Barton, President of the University ofAlaska Statewide System and a member of the OrganizingCommittee. On my immediate right is AcadendcianP.I. Melnikov of the Academy of Sciences ofthe USSR, Director of the Permafrost Institute ofYakutsk. Siberia, and the head of the delegationfrom the USSR. On my immediate left [not visiblein photograph] is Professor Shi Yafeng, Directorof the Lanzhou Institute of Glaciology and Cryopedology,and Deputy Chief, Division of Earth Sciences,Academia Sinica. He is the co-leader ofthe delegation from the People's Republic of China.Next is Mr. Daniel A. Casey, Commissioner of theDepartment of Transportation and Public Facilitiesof the State of Alaska, representing the Governorof Alaska. We are pleased to have Dr. Hugh Frenchof the University of Ottawa, and Chairman of thePermafrost Subcommittee of the National ResearchCouncil of Canada. He is representing the Canadiandelegation. Next to Dr. French is Mr. BillB. Allen, Mayor of the Fairbanks North Star Borough,Alaska. On my far left is Dr. J. Ross Mackay,Professor at the University of British Columbia,and former Chairman of the Ground Ice Divisionof the International Commlssion on Snm andIce, International Union of Geodesy and Geophysics.

2Scientists and engineers of the United States,and especially of Alaska, have waited many yearsfor this occasion, a time when the experts in thefield of the study of frozen ground from all overthe world would be gathered here in central Alaska,an area of perennially frozen ground. Althoughthe first invitation to meet here was issuedonly 10 years ago, at the Second InternationalConference on Permafrost in Yakutsk, Siberia,earlier workers dealing with frozen ground inAlaska, 70 and 80 years ago -- the gold miners --met have been thinking that miners in other countriessurely had easier ways to thaw the ground toobtain the gold than to use a little wood-burningsteam boiler that was available at the time.Those miners were not the first one6 to thinkabout permafrost in Alaska. The best-documentedearly account of permafrost is from a visit in1816 by the German explorer Lt. Otto von Kotzebue,to what is now called Kotzebue Sound in westernAlaska. He described che fossils in the frozenground at a place later termed "Elephant Point" bythe Englishman LC. Beechey in 1836, who also examinedthe permafrost cropping out in the seacliffs. Other early reports of scientists seekingremains of Pleistocene vertebrates in the frozenground also describe the permafrost phenornena.But it was the gold miners in central andwestern Alaska, from the end of the 19th centuryuntil the 1940'8, who were the main sophisticatedand msophisticated students of the study of permafrostin Alaska, but only as a by-product of extractingthe gold from the ground.Only 10 km from here, many a miner became alltoo familiar with the small scale problem of frozenground as he painfully thawed a shaft down tobedrock. Later, large-scale mining operationswere invented to remove the gold from the frozenground, creating probably the largest single artificialexposure of permafrost in North America,the Gold Hill Cut, which was 1.5 km long and 70 mdeep. It was from such exposures that basic informationon the origin and age of permafrost andassociated ground ice was obtained.But it was during and after World War I1 thatthe critical problems were encountered on a largescale--problem dealing with permafrost in theconstruction of airfields, roads, and buildings inthis perennially frozen terrain of North America.It was in 1944 that the first book in English onconstruction problem in permafrost terrain appeared.It was compiled from the Soviet literatureby Dr. Simon W. Muller.With the rapid growth of permafrost knowledgein the late 40'8, 50's and early ~O'S, investigatorsfrom the United States, Canada, and Siberiafelt more of a need to exchange information on aninternational scale, and a small internationalconference on permafrost, with mainly the UnitedStates, Canada, and the USSR participating, washeld in 1963, 20 years ago, at Purdue University.This has become known as the First InternationalConference on Permafrost. It wa6 followed by theSecond International Conference on Permafrost 10years later in Yakutsk, Siberia, under the guidanceof Academician P.I. Melnikov.In the last 10 years, studies on the scienceand engineering of frozen ground literally explodedin all areas, especially in two new majorfields, one dealing with the production and transportationof oil and gas in permafrost regions,and the other with the study of permafrost underthe sea, permafrost of the Arctic ContinentalShelf. These efforts, especially construction ofthe Alaska pipeline, have pushed the term "permafrost"and knowledge of its general importance intothe minds of the general public, es,peciallywhen it affects the price of the gasoline that manmust put in his automobiles.The Third Permafrost Conference was held inEdmonton in 1978, under the direction of the lateDr. R.J.E. Brown. It hosted 500 people, and 150papers were presented. Here, the western worldfirst learned of the existence and wide distributionof permafrost in the People's Republic ofChina, and of the research being undertaken onfrozen ground there. Starting with the Third Conference,details for the 5 years of planning forthe Fourth International Conference began to takeshape.Today, the Fourth International Conference onPermafrost, in the heart of permafrost country inthe United States, is finally underway, I havebeen told that, so far, 800 people have registeredand that 350 contributions are listed on the program.TO welcolne us here today, as the representativeof Bill Sheffield, Governor of the State ofAlaska, is his Commissioner of Transportation andPublic Facilities, Mr. Daniel A. Casey.

DANIEL A. CASEY - Thank you very much, Dr. P6wWe.Ladies and gentlemen, and distinguished foreignvisitors: First, let me say that I hope you havetime to get Out and do a little playing and notonly working and studying. I knw that such isyour primary reason for being here, but Fairbanksis one of the best places to be in Alaska in thesummer. I hope that you have taken the time toschedule so= fishing, sightseeing, or a leisurelytrip outside the state at the end of your conference.On behalf of Governor Sheffield, it gives regreat pleasure to extend a welcome to the scientistsand engineers from all over the world whohave assembled here for this conference. As Commissionerof the Alaska Department of Transportationand Public Facilities, I can say my departmentdeals daily with the broad range of permafrost-relatedproblems, which affect highways,bridges, airports, and shortly, I imagine, railroads,building foundations and communicationsupportingstructures. It is also for this reasonthat the department, on behalf of the Stateof Alaska, is a co-sponsor of this conference.Because permafrost underlies more than fourfifthsof our state, we are continuously affectedby the engineering challenges presented to us bythese phenomena, and we mst rely on the other polarcountries to help UE solve these challenges.Many of these problems will be evident to those ofyou who take the local field trips or who have hadan opportunity to go to Prudhoe Bay or down theRichardson Highway. The problem are unique andfascinating; and so are some of the solutions.They sometines prove an embarrassment to the engineersof our department, as the traveling publicassumes that we have ready solutions in hand. Iam proud to note that several employees of the Departrnentof Transportation will be presenting someof these solutions in papers during this conference.Just prior to joining the Governor's cabinetearlier this year, it was my pleasure to head theAtlantic Richfield Company's construction programat Prudhoe Bay. Over the six years that I wasassociated with that effort, my understanding ofpermafrost grew tremendously. The project, whichmany of you have had or will have an opportunityto see on the North Slope, began in the classicphases that a project goes through, but compoundedby the fact that it was in the Far North. Thefirst question that we were challenged with backin 1974-1975 in the design phases was: Would itwork? If we put those big modules on pilings,would they sink into the ground or would they stayup? And, of course, some of the more subtle questionsin tern of long-term creep and road stabilityand road clearing were foremost in our minds.As everyone knows, those challenges were met,just as the challenges of road construction andbuilding construction throughout the state havebeen met. But I share with you one personal perspective,and that is that the challenge today inpermafrost engineering is not what will work, butwhat will work most efficiently. How can we dothe same things that we have now become accustomedto doing in the permafrost regions, but do themfor fewer dollara so that we can get further alongin the construction of our facilities and so theycan last a longer time.Let me close with a final comment. It hasbeen stated in the scientific community that aglobal warming trend may be at hand. It would beuseful, I think, for US practitioners if you discussedyour outlook on the global warming trend.And if Alaska is to be faced in the foreseeablefuture with such a warming trend, as wel as therest of the polar-rim countries, we need to knowthe significance of that trend and the timing ofit. As a consequence of this threat, our highways,airports, bridges, buildings, and pipelinesthat are built on permafrost may face an increasingrate of deterioration as their foundations,potentially, slowly give way. We need to knawfrom you how serious this future threat is, andhow, if at all, we should plan for that possibilityin today's designs.Again, on behalf of the Governor of Alaska,and the Alaska Department of Transportation andPublic Facilities, welcorne to the United Statesand our state.TROY L. Pdd - The next speaker might be describedas the host of the conference, inasmuch as he isDr. Jay Barton, President of the University ofAlaska Statewide System. Dr. Barton is not onlyin a position to weLcome us to the University, buthas been an integral part of the Organizing Committee,involved with the production of the con-

4ference on local and international scales. Ladiesand gentlemen, the President of the University ofAlaska, Dr. Jay Barton.JAY BARTON - Dr. PBwB, distinguished guests, fellowscientists, ladies and gentlemen: It is withhonor and pride that I welcome you on behalf ofthe Board of Regents of the University of Alaskato the Fourth International Conference on Permafrost.It is a truly significant occasion for theUniversity of Alaska and one that is quite appropriateto its mission. You know, some years ago,Clark Kerr, in a facetious moment of whirnsy, saidthat a modern university is really little morethan a collection of conflicting constituenciesheld together mostly by a commn heating systemand a common shared grievance over parking. Butit is on an occasion like this, I think, that werecognize the university for what it truly is, acommunity of learners, young and old, each learningfrom the other. This is, in Jacques Barzun'awords, the house of intellect.Scientists are fond, perhaps, of being picturedas solitary thinkers. You all saw the SigmaXi report the other day that showed a little cartoonof a scientist in deep thought wearing a T-shirt that said, "I think, therefore I am paid."But, actually, I think we are very gregariouspeople, because it is in our interactions witheach other that we apply the error-correctingwchanism that is intrinsic in our scientificmethod. It is through the free exchange of ideasand knowledge at conferences like this, bringingtogether scientists from throughout the world,that we deepen our understanding of nature andthat we corn close to achieving some measure ofscientific truth. It is through the free exchangeof ideas and knowledge at conferences like this,which bring together scientists from throughoutthe world, that we come close to achieving truepeace.I hope that you enjoy your sessions in thenext week. Welcome to the house of intellect, tothe University of Alaska.TROY L. P i d - The University of Alaska and rhearea where we'll be investigating permafrost onlocal field trips, as well as the City of Fair-banks, falls in an area called the Fairbanks NorthStar Borough. This is a vital area in centralAlaska, and here to welcome you for the Borough isthe mayor, Mr. Bill B. Allen.BILL B. ALLEN - Ladies and gentlemen, and honoredguests visiting from foreign countries: Welcometo our part of the world. Fairbanks North StarBorough is certainly proud to have the Universityof Alaska at Fairbanks as a site for your conference.A tremendous mount of energy has been putinto this conference by the organizers and contributors.Fairbanks, the Golden Heart of Alaska,is honored that those efforts have culminated inour community with this conference. Thank you forcoming to our home, and I hope that you will makeit your home in the next week. I have seen fromyour program that many of you will be participatingin some of our local activities while you arehere. I encourage you to take advantage of variousattractions in our fine community during thenext five days. As noted in your schedule, ourGolden Heart City is celebrating its annual GoldenDays, which commemorate those pioneers who camenorth at the turn of the century, seeking theirfortunes in gold. And although some found gold,more found permafrost. So enjoy the hospitalityof our horae as we re-create and remember those whostruggled in this land, and who founded our community.To give those of you who are visiting UB someperspective of our community, the local governmentis responsible for an area larger than NorthernIreland. We have a population of some 60,000people and an abundance of geological features.To put that in the context of this conference, wehave more permafrost per capita than anywhere elsein the United States, and I might add that this isone reason why this conference should be held herein Alaska. We certainly hope that we have an opportunityto host you again. We have numerous examplesof permafrost-related phenomena for yourfield trips, especially prepared for you. Also,we have nice weather for you, by proclamation ofthe mayor. Strange that we do have those powers,but we do. We have plenty of thermokarst pits,pingos, and frost heaves. I would suggest that wehave more frost heaves per road mile than anywhereelse in the United States. Just ask Mr. Casey

5about his budget for maintenance. Or, just drivedown any one of our roads a year after it has beenconstructed and you will see that this is an excellentlaboratory for gathering information onsome of the permafrost problem which are faced byurban centers.As a practical matter, our community is interestedIn promoting research with which you areinvolved. We are glad to have you observe thetypical permafrost features of this area, becausewe are searching for solutions to the problemsthat they cause. That was obvious to me on my wayhere this morning. I live out on Farmer's LoopRoad; I hit a permafrost bump that was not there aweek ago, and I almost broke my neck. I hope thatyou will do something about those types of things,and help us with our problems in that area. Withsituations like this all around us, it is easy tosee that the people of Alaska are interested inthe research that you are doing. I support usinglocal government resources in finding answers thatare essential if we are to understand and live inharmony with the permafrost that permeates our existencein so many obvious ways. And as a localgovernment representative, I will work to encouragethose at the state, national and internationallevels to make the necessary financial and moralcommitments to help you find answers to the questionsthat you will be addressing this week. Theyare questions that impact the people who live inthis region of the Borough and who must continuallycope with the idiosyncrasies of permafrost.We have been anxiously watching the progressthrough the United States Congress of the ArcticResearch Policy Bill, which is sponsored by ourSenators Stevens and Murkowski. This conferencehelps reinforce the needs which legislation fulfillsfor the development in the United States ofa national policy on arctic research. We are oneof the few nations with territories in the Northwhich is still without such a policy. I am excitedabout the potential positive impact as a resultof the passage of this legislation. Not only willthe proposed legislation establish a national arcticpolicy, it will simultaneously provide for aclearing house to facilitate better coordinationand reduce duplication in research. It also proposes$25 million annually in research funds.This focused effort is essential if the UnitedStates accepts its role in the responsibilities asa partner nation of arctic communities.The U.S. should provide specific support forbasic research, which is essential in the developmentand preservation of community environments inthis region. Unique problem pose interestingchallenges to those who wish to live, work, orplay in this part of the world. The true potentialof our community, our state, and all regionsof the Arctic and Subarctic cannot be reached untilour leaders recognize the importance of thetype of work which this conference most aptly represents.We mst all do what we can to promotethe education of those who will be making thosedecisions which have an impact on the course ofarctic research.In closing, let me thank you again for thecontributions you have made in permafrost research,which have helped many people of the worldto cope with the environment they live in. We areglad you have come to our community. We look forwardto the conference and papers which will beoffered this week and to supporting your effortsin the future. Thank you.Dr. PLw6, I have a Proclamation, if I cotiidtake a minute to read it [see next pegel.TROY L. Pgd - Thank you, Mr. Allen, for the invitationto inspect your permafrost. I am sure thatin the next few days we will be examining exposuresof frozen ground here and the effects offrozen ground on life in the North.In this opening session, it is our privilegeto have soue information presented on the natureof the latest research and related activities goingon in the countries of the world, especiallyin the major areas where permafrost is being studied.First, I would like to call on AcademicianMelnikov, who has long been the leading figure inthe study of perennially frozen ground in the USSRand the chief delegate of the USSR to all the InternationalPermafrost Conferences. He was hostfor the Second Conference in Yakutsk in 1973.Academician Melnikov.P.I. MELNIKOV - Respected colleagues: On behalfof the Soviet delegation, I would like to greetall the participants of this outstanding geocryologicalforum who have assemblediHete in the wondrousState of Alaska to bear witness to the

7achievements made in fundamental and applied geocryologysince the third conference.It has been five years since the Third InternationalConference on Permafrost was held in Canada.We fondly remember the organizers of thatconference who did their best to make the sessionsand field trips as interesting as possible. Weregret that two prominent Canadian geocryologists,Dr. R.J.E. Brown and V. Poppe, who did much to developthis science in Canada and to further scientificcontacts with foreign geocryologists, havepassed away.In the course of the past five years, fundamentaland applied geocryological studies haveprogressed together with the industrial and economicdevelopment of northern permafrost regions.The principal results of these investigations areset forth in the reports. Due to considerablescientific and practical effort, we have been ableto increase the efficiency of the development ofnorthern territories which are rich in natural resources,including precious minerals.Exploration and extraction of these minerals,however, han proven to be both an expensive anddifficult undertaking. Science is now faced withthe task of developing new, more effective researchmethods, which include satellite and geophysicalsurveys. We must increase both the depthand the reliability of our data. We must alsocreate more precise instruments and maximize automationof research observations and data processing.It has become necessary to perfect methodsfor interpreting satellite imagery and to equipthese satellites with instruments capable of determiningnot only the presence of permafrost, butalso its thickness, ice content, discontinuity andthe depth of seasonal thawing. It is also desirableto monitor the thermal-physical characteristics.These data will, to a great extent, facilitatethe study of vast, almost inaccessible territorieslying within the permafrost zone. We mustlearn more about permafrost evolution, composition,texture and conditions for distribution.The perennially frozen ground in a major portionof the extreme north contains considerableground ice underlying the thick, thermal-insulatingpeat and moss cover. Disturbance of this coverresults in the formation of thermokarsts andthaw basins. It has therefore become necessary todefine strict regulations governing economic de-velopment, land use, construction and environmentalprotection in these territories.In order to successfully develop permafrostregions, we should extend the training of geocryologists.Both Moscow State University and YakutskState University have departments of geocryologyand cryology. There are also special geocryologicalacademic councils which monitor doctoraland candidate theses in the technical, geological,and geographical sciences. Geocryologistsworldwide should make a greater effort todevelop this science, while maintaining close scientificcontact with their colleagues in othercountries.We wish all of you every success in your scientificwork and in the activities in this conference.TROY L. PgWd - Our next speaker, representing thedelegation of the People's Republic of China, IsProfessor Shi Yafeng, who is Director of the LanzhouInstitute of Glaciology and Cryopedology ofthe Academia Sinica. We has been one of the organizersof permafrost research in China for manyyears.SHI YAFENG - Mr. Chairman, ladies and gentlemen:First of all, on behalf of the delegation of thePeople's Republic of China, I would like to expressour heartfelt thanks to the organizers fromthe National Academy of Sciences, the State ofAlaska, and also the University of Alaska, and especiallyto Professor Troy L. P&d, Professor GunterWeller, Dr. Jerry Brown, and all the membersof the U.S. Organizing Committee for the excellentand persistent work required to prepare such alarge conference. Please accept the sincerethanks of the Chinese delegation. This conferenceis really well organized, and it will greatly promoteresearch and development in the world.As we all know, permafrost program have animportant effect on the economic development ofcold regions. China is an ancient civilized countrywith a long history. About 2,000 years ago,seasonal freezing processes in China had alreadybeen decoded in the ancient Chinese classic, theBook of Leaves, as follows: In the first eventsof winter, earth and water begin to freeze; in the

8second, ice becows hard, and earth cracks; in thethird, freezing reaches its climax. And in theevents of spring, thawing is promoted by an easterlybreeze.Permafrost in China is estimated to underlieabout 2 million square kilometers, second only tothe USSR and Canada. If we include ground that isseasonally frozen to a depth greater than 1/2 meter,the frozen ground occupies two-thirds of theentire country. Such a wide area of frozen soilexerts a great influence on China's economy, butit also expedites the study of permafrost inChina. Since the founding of the People's Republicof China in 1949, 2000 kilometers of railroads,several thousand kilometers of highways,and many other types of construction, includingcoal mining, irrigation canals, oil pipelines, industry,and civil facilities, have been built inpermafrost areas. All these construction projectsencountered many difficulties; therefore, it wasnecessary for several study groups on frozenground to be successively established in the Departmentof Railways, the Department of Water Conservancy,the Department of Forestry, and the Departmentof Construction. In the 1960's, a specialpermafrost research institute was also establishedwithin the Chinese Academy of Sciences,Academia Sinica, and also in the Chinese Academyof Railway Sciences. During the 10 years of disturbanceof the so-called Cultural Revolution, in1966-1976, permafrost research in China was inactive.In 1978 the First National Conference on Permafrostwas held. Only 68 reports on permafrostwere presented. Three years later at the SecondNational Conference on Permafrost, held in 1981,185 papers were presented. Now the study of permafrostin China includes permafrost, physical andmechanical processes of frozen ground, perfectingand testing techniques, and engineering constructionproblems in frozen ground. Permafrost researchin China is still young, and we need tolearn much from other countries, so that we canattain a higher level for the benefit of China'smodernization. We welcome all types of cooperation,including the exchange of data and publications,and the exchange of scholars and graduatestudents to do such cooperation can be developedfurther. The Chinese delegation also supports theproposed International Permafrost Association, sothat international cooperation in research on permafrostcan more effectively be realized.The Chinese delegation wishes to expresswarmest congratulations on the successful openingof the Fourth International Conference on Permafrost.We wish all the members of this conferencea healthy and happy time.TROY L. P6W6 - Thank you, Professor Shi. Our nextspeaker is Dr. Hugh French, who chairs the delegationfrom Canada at this meeting.HUGH FRENCH - Mr. Chairman, ladies and gentlemen:On behalf of the Canadian delegation, I wish tostate that we are very pleased to be here at theopening of the Fourth International Conference onPermafrost in Fairbanks, Alaska. As many of youmay remember, Canada was the host of the Third InternationalConference on Permafrost, held in Edmontonin 1978. As such, we are very well awareof the tremendous amount of planning, time, andenergy which must have gone into the preparationof this particular conference. We are sure thatit will be successful, and we look forward tolearning new things, renewing old acquaintances,and making new friends.Permafrost is particularly important to Canada,since it underlies approximately 50% of ourcountry. The permafrost regions are vast and extendwithin 1200 km of the North Pole. They includeextensive areas of polar desert, of tundra,and of boreal forest, with a wide diversity ofgeological and topographic conditions. Some ofthese areas are rich in renewable and non-renewableresources. Their development, to the nutualbenefit of northern indigenous people and of theCanadians, presents nunwow challenges, which aretechnological, scientific, and social in nature.In Canada, we are anxious to meet these challenges,and to learn through the experiences ofothers.For these reasons, Mr. Chairman, Canada isespecially glad to participate in this Fourth InternationalConference on Permafrost.I would now like to take this opportunity tobriefly highlight some of the recent events whichhave occurred in Canada since the Third InternationalConference in 1978.

First of all, as has already been mentioned,the death of Roger J.E. Brwn, under whose leadershipthe Third International Conference was organized,and who was a major pioneer of permafrostscience in Canada, was a great loss. He was welknown both nationally and internationally, andwill be difficult to replace,Let me turn now to the current state of permafroststudies in Canada. An ever-increasingnumber of individuals, agencies, and organizationsare becoming involved in permafrost problem inCanada. At the same time, these problems are becomingmore complex and multi-disciplinary in nature.One of our strengths, perhaps, In Canada,is in the private sector where, in addition to majorindustrial and commercial concerns, a numberof engineering and consulting companies now possessconsiderable experience with permafrost-relatedproblems. Drilling technology in the search€or oil and gas in the Far North is an importantarea of current concern. Problems are encounteredand compounded by the occurrence of substantialareas of offshore permafrost in the Beaufort Sea.Gas hydrates are now recognized as important, buttheir nature, occurrence, and distribution arestill little known in Canada. The question ofpipelining in permafrost is also of current concernto us. The proposed gas pipeline from Alaskathrough the Yukon, and the possibility of transportinggas from the high Arctic islands to southernmarkets, are central to our concerns. Finally,there is the broad area of permafrost engineering;in Canada we are continually seeking toimprove our engineering design and constructiontechniques in the permafrost zones. Linked withthis is the realization that permafrost science,involving the origin, distribution, and nature ofpermafrost, and related fields such as permafrosthydrology, are essential to sound engineering design.The Government of Canada, through its variousagencies and departments, is very active in permafrostresearch. The Department of Energy, Mines,and Resources, the Department of Indian and NorthernAffairs, the Department of the Environment,and the National Research Council of Canada areall currently undertaking major programs designedto increase our understanding of both permafrostscience and engineering in Canada. Other departments,such as the Departnent of Transport andPublic Works, and the various provincial and ter-ritorial agencies are active at the practical level,providing the infrastructure for resource developmentin northern Canada.A number of universities are developing expertisein permafrost-related problems. There isalso the strong possibility that a major cold regionsengineering research center supported by theNational Research Council of Canada will be establishedin the next few years in western Canada.Many of the recent advances in permafrost researchin Canada were summarized at the FourthCanadian Conference on Permafrost, held in Calgaryin March of 1981. This conference saw the presentationof over 100 scientific papers and broughttogether over 250 scientists, including a numberfrom outside of Canada, Ten sessions were organizedat that meeting, dealing with such topics aslaboratory testing of frozen soils, permafrost hydrology,climate and permafrost, gas hydrates, andengineering applications. Now, just two yearslater, many of these saw people are here in Falrbanksand are presenting more of their findings.They are evidence of the extremely rapid pace ofcurrent permafrost research in Canada.To conclude these brief remarks, Mr. Chairman,I would like to restate our pleasure to behere in Alaska at the opening of the Fourth InternationalConference on Permafrost. Many of ushave seen, or will see, during the next few dayson the field excursions, some of the progress thathas been made here in Alaska, much of it at theUniversity of Alaska in Fairbanks, towards thesolving of permafrost problems. It is very impressiveand we look forward to learning much morein the next few days. Thank you very much.TROY L. Pfid - Thank you, Dr. French. I think itwould be wel at this time for the U.S. OrganizingCommittee to acknowledge the great amount of helpit received from the Canadian colleagues. Theirrecent experience in organizing an internationalconference was most helpful to us. The effortthat they put forth in working with our programand in running one of the major field trips, aswell as in the review of many of the contributedpapers, is greatly appreciated. We wish to particularlyannounce our thanks to the Canadiangroup. Our next speaker is Dr. J. Ross Mackay,leading permafrost researcher and holder of manyhonors. He is a long-time friend of the late Dr.

10Roger J.E. Brown of Canada, who has been mentionedtwo or three times already. Dr.Brm participatedin the first three congresses and it is known thathe was, of course, the chairman of the third conference.At this time: Dr. Mackay.J. ROSS MACKAY - Mr. Chairman, ladies and gentlemen:I have been asked to say a few words in remembranceof the late Dr. R.J.E. B K ~ . As manyof you know, he died in 1980 after a long andcourageous struggle against cancer. It was justfive years ago last week that Canada hosted theThird International Conference on Permafrost atEdmonton, Alberta. Roger was the perfect choicefor chairman of the Canadian organizing committee.Much of the success of the conference wasdue to Roger's unselfish and untiring efforts.He was as much at home with permafrost scientistsfrom the United States and abroad as he was withhis fellow Canadians. He traveled in the SovietUnion and the People's Republic of China, alwayswith the objective of fostering friendships andinternational collaboration. Roger had the cheerfuland infectious smile, a genuine interest inpeople, and a happy facility for making friendships.He had looked forward with great anticipationto being able to attend this Fourth InternationalConference on Permafrost which is beginningso auspiciously today. In tribute to Dr. Brown,the proceedings of the Fourth Canadian PermafrostConference were published last year in a memorialvolume. The Canadian Geotechnical Society has establisheda Roger J.E. Brown Memorial Award, whichwill be presented for outstanding contributions topermafrost at the next and future internationalconferences on permafrost.TROY L. P$d - Thank you, Dr. Mackay. Our nextspeaker is Dr. Jerry Brown, who is Chairman of theCommittee on Permafrost of the Polar ResearchBoard of the United States National Academy ofSciences.JERRY BROWN - Mr. Chairman, ladies and gentleuen:On behalf of the U.S. National Academy of Sciences,and its president, Dr. Frank Press, it ismy pleasure to welcome the participants to theFourth International Conference on Permafrost. Iwould like to thank our hosts here in Alaska andat the university for providing this opportunityto meet in Fairbanks. Dr. Gunter Weller, ViceChairman of the U.S. Organizing Committee, deservesparticular thanks for undertaking the localarrangements, Special acknowledgment is appropriateto our Canadlan colleagues who have providedconsiderable assistance in the review process forthe contributed papers and In undertaking thepost-conference field trip to the Mackenzie RiverValley.In the remaining few minutes of this openingsession, I would like to briefly discuss the statusof permafrost research in the United States.Scientific and engineering investigations on frozenground are conducted by many institutions andorganizations, including universities, federal andstate organizations, and privately financed industrialorganizations. Numerous professional organizationsare involved in organizing meetings, seminars,and conferences on the subject of permafrostand freezing and thawing of soils. Notableare the American Society of Civil Engineers andthe American Society of Mechanical Engineers. Thegeographic and disciplinary diversity of theseU.S. activities is characterized by the approximately100 U.S. papers which will be presentedduring the next five days. A special conferencebibliography produced by the World Data. Center forGlaciology in Boulder, Colorado, identifies manyother U.S. publications which have become availablein the last five years.Current investigations are underway in threemajor regions: (1) offshore or subsea permafrost(particularly in the Beaufort Sea), (2) land-basedpermafrost areas in Alaska, and (3) in the alpineregions of the contiguous United States. In thepast five years, major efforts have been directedto the continental shelf in association with petroleumexploration. There the occurrence anddistribution of ice-bonded permafrost has beenidentified by both drilling and geophysical methodsoff Prudhoe Bay and in Harrison Bay.On land in the Arctic, the temperature anddepth distribution of permafrost have been furtherdefined using boreholes drilled for oil exploration.The bottom of ice-bearing permfrost hasbeen delineated through the examination of boreholedata from the arctic coast to the BrooksRange. The distribution of near-surface massiveice has been further characterized. The occur-

ence of gas hydrates in both land and subsea permafrostis being examined. Considerable attentionhas been directed to concerns regarding potentialchanges in permafrost terrain due to human activitiesand carbon-dioxide-induced climatic warming.In the Subarctic, or in the region of discontinuouspermafrost, investigations continue onconstruction and maintenance techniques to mitigateadverse effects of permafrost degradation andfrost heave. The influence of permafrost on surfaceand groundwater supplies continues to be investigated.In alpine regions, the general distributionof permafrost has been delineated and severalsire-specific studies are underway. In the Antarctic,permafrost research is generally conductedin relation to periglacial and geologic investigations.In the past year, the U.S. Committee on Permafrostundertook and completed an assessment offuture permafrost research requirements for therewining years of the twentieth century. Includedin this study are assessments on subjects relatedto the chemistry and physics of frozenground, subsea permafrost, geophysical techniques,soil mechanical behavior, engineering and environmentalconsiderations, and hydrology. A series ofrecommendations include the need for additionalresearch on ground ice, its detection and origin,monitoring of performance of existing facilitieson permafrost, monitoring of active layer andground temperatures, and continued internationalcooperation. A second study on ice segregationand frost heaving is also to be published. It isobvious that there remains a need for additionalbasic and applied research on permafrost and deepseasonally frozen ground. This conference willhelp to identify what research should be conductedin the future.In closing, I wish you a successful conference.It is gratifying to me to see such a largeattendance from so many countries. Thank you.TROY L. Pfid - Thank you, Dr. Brown. One of themost pleasing aspects of the opening session is tobe able to acknowledge the great supporting staffthat worked virtually for years to produce thisconference. The unfortunate aspect is that thegroup is so large that all the supporting workerscannot be mentioned here, but their nares will appearin the final conference publications.The Organizing Committee of the conferencehas worked for five years on this effort, and Iwould especially like to mention the tremendouscontributions of Jerry Brown, Gunter Weller andLou DeEoes, who were active in all aspects of theconference. Also, Richard Reger for overseeingthe publication of the guidebooks, Robert Millerfor chairing the review of manuscrlpts €or theproceedings, Oscar Ferrians for guiding the fieldtrip details, and especially Jay Barton for hiesupport in many national and local details.Thanks are also extended to Hans Jahns, JohnKiely, Art Lachenbruch, Link Washburn and Jim Zumberge.Special mention mst be made of Wil Harrisonand Bill Sackinger, of the University of Alaska,along with Gunter Weeller, for arranging the programand the host of local details. Also, specialthanks to Dixie Brown, for organizing the privatecontributions. It is well known that this conferenceis possible only with the tireless support ofthe office staffs of these individuals, and oursincere thanks goes to the small army of secretaries,clerks, and aides who have been working onthis conference for so long here in Alaska and inthe contiguous states. Special thanks are extendedto the Department of Conferences and Institutesof the Universlty of Alaska.Financial support for the conference has comefrom various sources. hbnetary contributions havebeen received from the State of Alaska, Federalagencies, and the private sector. A list of thesebenefactors is presented in several of the conferencepublications (see page 413). In addition, valuablein-kind support has been received from ahost of institutions, especially from the Cold RegionsResearch and Engineering Laboratory and theGeophysical Institute of the University of Alaska.Before concluding, I call your attention tothe banner on the table in front of re. To thosewho are not aware, the circles you see there arelogos that were used in this and the previous conferences.The banner originated with the Canadiandelegation five years ago and was passed on to theU.S. for this conference.We again welcome you and appreciate your coming;have a successful conference. This concludesthe opening session. Thank you.

12PROGRAMMONDAY TUESDAY WEDNESDAY THURSDAY FRUlAYTIME 18 July 19 July 20 July 21 July 22 JulyPanel Session: Panel Session: Panel Session: Panel Session:8:30 Opening Environmental Deep Foundations Frost HeaveSubseato Plenary Protection and and Permafrost1000 a.m. Session of Embankments Ice SegregationPermafrost Terrain10:ML1030 a.m.Coffee Break12:00noon""12:30 p.m.""1:30 p.m.2:oO p.m.""""3:3&4:00 p.m.Panel Session:PipelinesinNorthern RegionsLUNCH12:00-1:30*Thermal design*Pipelines*Ice and soil wedges*Invited ChineseSessionCoffee Break*Thermal analysis*Mechanics of frozen4:00 soilsto *Pleistocene perma-6:oO p.m. frost conditions*Invited ChineseSession*Remote sensingPaper Sessions:*Thermodynamics*Mechanics of frozensoils*Mountainandplateaupermafrost*Effects of man-madedisturbance*Planetary permafrostPoster SessionLocalFieldTripsBARBEQUEPaper Sessions:*Roads and railways-Thermal aspects*Foundations*Frost mounds andother periglacialfeatures*Effect of man-madeand natural disturbance*Invited Soviet SessionPoster SessionLUNCH 12:30-2300 p.m.Panel Session:Climate ChangeandGeothermalRegime-Coffee Break*Foundations*Ground ice andsolifluction*Hydrology*Invited SovietSession*ClimatePaper Sessions:*Frost heave*Embankments, roadsand railways*Patterned ground*Hydrology*GeophysicsPoster SessionLocalFieldTripsBANQUETPaper Sessions:*Excavations, miningand municipal*Cold climate rockweathering*Groundwater in permafrost*Subsea permafrost*Ecology of naturalsystemsClosingPlenarySessionWalkingTourofLocalPermafrostFeaturesSee Appendix A for descriptions of local field trips. See Appendix B for titles of presentations.

Reports of Panel SessionsDuring the early planning for the Fourth International Conference on Permafrost,there was a consensus that certain topics of high current interestwould be highlighted. and in as interesting a fashion as possible. The latterrequirement seemed to rule out the presentation of invited review papers by individualsas at past conferences, but at the same time the tremendous value ofthe written versions of these reviews was recognized. This led to the idea ofreplacing single authors with panels of international experts on each of thetopics to be highlighted. Each panel was scheduled for a plenary session duringwhich no other activities were to take place. In these sessions, each panelreviewed its topic and, if time allowed, provided a discussion with audienceparticipation. It was felt from the beginning that whatever the outcome of thepanels at the conference, their most important task, just as with invitedspeakers of past conferences, would be the production of written reviews ofeach of the topics highlighted.These reports follow, but not in the order of the program presentation.They are based on the reviews of subfields supplied by each panel member to hispanel chairman. The degree to which these components have been integrated bythe chairlnen varies, but in most cases they remain relatively unmodified despiteeditorial changes. As such, they are not of uniform length, style, orformat. On the other hand, together with the introduction of the panel chairman,they bring a depth of perspective and diversity to a topic that would bedifficult for a single author to duplicate. Recommendations for future researchand engineering investigations are considered the opinions of the panelmembers and do not necessarily reflect the opinion of the publisher.A great deal of credit is due to the panel chairmen and to the panel rembers.Each panel chairman selected and organized his own panel, a task madeparticularly challenging by its international composition and by the uncertaintyas to whether all the panel members could attend the conference. Some ofthe originally designated chairmen and panelists were indeed unable to attend;particular credit is due to the replacements who assumed responsibility on relativelyshort notice. Both the Soviet and the Chinese panelists submittedtheir contributions in English, which greatly aided the panel chairmen, allNorth Arricans, in organizing and presenting the panel reviews.William D. Harrison, ChairmanProgram CommitteeUniversity of Alaska13

Deep Foundations and EmbankmentsPANEL MEMBERSNorbert R. Morgenstern (Chairman), University of Alberta, Edmonton, CanadaS.S. Vyalov, Research Institute of Foundations and Underground Structures, Moscow, USSRDing Jinkang, Northwest Institute, Academy of Railway Sciences, Lanzhou, People's Republic of ChinaDavid C. Esch, Alaska Department of Transportation and Public Facilities, Fairbanks, Alaska, USAFrancis H. Sayles, Cold Regions Research and Engineering Laboratory, Hanover, New Hamp! shire. USABranko Ladanyi, Ecole Polytechnique, Montreal,CanadaINTRODUCTION bearing characteristics of single reinforcedpiles, the freezeback rate of soi 1 around a pile,N.R. Morgensternconcrete for use under negative temperatures, theresistance of foundations to frost heave, andmethods for protecting pile foundations fromThis panel presentation combines two of the frost-heaving. As a result of experience variousmost important aspects of permafrost engineeringproblems have been identified, and they are dis--- deep foundations and embankments. The underly- cussed.ing theme of the presentation is to review currentA distinction is made between roadlrailwaypractice, identify deficiencies. and draw atten-embankments on permafrost and water-retaining emtionto the major problems that need further at- bankments. The review of current practice for thetention. The validation of current practice from design of road and railway embankments distinperformancerecords is emphasized wherever possi- guishes between the preliminary investigationble.phase, the design stage, the construction stage,The presentations concerned with deep founda- and the maintenance and operation stage. A varitionsconsist of three regional reports. The re- ety of research needs for each of these stages isport on North American practice discusses develop-identified. Examples include the need for remotements related to pile installation methods, thedetection of subsurface conditions that affect embehaviorof piles under load, the improvement of bankment performance and the need to quantify thebearing capacity using special types of piles, and thermal effects of alternative embankment sideniledesinn. It concludes that we now have a rel- slope surfaces, surface vegetation covers, and theyatively good idea of how a pile, installed by arole of snow-cover in embankment performance.given method, will behave under an axial load.Several case histories of embankment performanceMuch less is known, however, about the effect ofare discussed.seasonal changes of permafrost temperature on pill eBoth Soviet and North American experiencebehavior. The need for more studies of thermo-with water-retaining embankments in permafrost ispiles is emphasized.summarized. The indications are that the design,Current Soviet practice in pile design andconstruction, and maintenance of safe, economicalconstruction is reviewed. Emphasis is given toearth dams and the preservation of natural slopessome of the soecial oroblems that arise in weaker in the Arctic and Subarctic are strongly dependentsoils and to methods for improving and validatingpile foundations in frozen ground.upon such considerationsseepage control, handlingas structural stability,of materials, erosionIn China, deep foundations in permafrost have control, and the environmental effect of the imbeentested and used since the early 1960s. The poundment. Extensive development of both analytitypesemployed are described. To provide a basis cal and construction techniques is required to adforrational design, studies have focused on the dress the attendant problems.15

PLACING OF DEEP PILE FOUNDATIONS IN PERMAFROST IN THE USSRS.S.Vyalov"Research Institute of Foundations and Underground StructuresMoscow, USSRIn the Soviet Union, data on the design andplacement of pile foundations acquired and verifiedthrough research and practical experience arepublished in the Building Codes and Regulations(BCLR) "Foundations in Permafrost, 1977" and "Manualfor the Designing of Foundations in Permfrost,1980."TYPES OF PILES AND PILE-DRIVING TECHNIQUESThe following types of piles are in use: reinforcedconcrete, metal, wood, composite, encased,and pillar piles.The techniques of driving piles are as follws:(a) At sites where no thawing of permafrostis employed, use is made of frozen-in (floating)piles driven with the aid of steam. Suitable alternativesare to lower piles into boreholes andthen fix them in place with soil mortar poured intothe holes, and piles driven into small-diameterpilot boreholes.(b) At sites where the thawing of permafrostis used, the recourse is to strutted piles anddeep piles bearing upon ground that displays lowcompressibility.PRINCIPLES OF PILE DESIGNPiles of all types are designed to ensure arequisite bearing power (strength), Those used infrozen plastic soil and ice-rich ground are designedwith due regard for the deformation (settlement)of the soil.In proportioning frozen-in piles to obtainadequate bearing power, the long-term ultimate,shear strength along the side surface of the pile(the adfreeze strength) is taken into account aswell as the long-term ultimate strength of thesoil resisting the end bearing of the piling.Recomnended design values of the strength characteristicsare given in the BCLR. The settlementof soil is assurned to be nonlinear.Computer-aided solutions obtained by usingthe finite element method have been reduced tosimple formulas that permit calculations to becarried out with the aid of alignment charts. Inaddition, a formula that incorporates an equationof creep for settlement and an equatioa of longtermstrength has been derived that paves the wayto designing in terms of both strength and deformationwith due allowance €or time.*Not present; summary presented by N.R.B tern.Morgen-Horizontal loadings are measured, taking intoaccount the various restraints on the pile in thepermafrost layer (depending on the depth of seasonalthawing and the permafrost temperature).The criteria for designing laterally supportedpiles for thawing soils include the strength oflow-compressible underlying rock that resists indentationand the strength of the pile materialwith due allowance for its buckling, Extra loadingdue to negative friction is also taken intoaccount.Strength of Freezing of a Pile to the SoilThe physical essence of the strength offreezing has been examined, noting that a film ofice form at the interface between the soil andthe pile. The shear strength of frozen soil isthought of as a sum of the freezing forces at theinterface and the frictional forces arising fromthe radial compaction of the soil. An equation oflong-term shear strength of frozen soils has beenderived. A comparison of the shear strength ofthe soil mortar at the interface with the pile afterfreezing v8 the shear strength of the frozensoil mortar at the interface with the surroundingfrozen soil has revealed that in the forraer casethe shear strength is lower. A method of designingpiles for weak soils (saline, ice-rich, clay)has been developed based on the assumption thatthe strength of the soil mrtar at the side surfaceof the pile and that at the perimeter of theborehole are the same.Design values of the long-term ultimatestrength of several kinds of frozen soils varyingwith temperature have been determined at the surfacesof reinforced concrete, metal, and woodpiles; similar values of the strength of soil andsoil mortar at the periphery of the borehole havealso been determined.An equation of long-term strength for varyingtemperature and loading has been derived, based onthe kinetic theory of strength.Improvina the Efficiencyof Pile FoundationsAn increase in pile capacity and a decreasein costs may be achieved by- resorting to composite woodfconcrete orwood/metal piles;- duuping crushed rock into pilot boreholesor'using concrete pipes with bulb-shaped bases;- pouring soil mortar of an optimum compositioninto boreholes;- artificially chilling high-temperature permafrost,including the use of thermopiles;- ensuring the setting of mlded-in-placeconcrete piles at the permafrost interface;16

17- streamlining pile design so that variabletemperatures and loading are taken into account.Allowance for Variable Temperature and LoadingThe existing method of structural analysisrelies on the least favorable conditions, pilesbeing designed on the assunption that the permafrosttemperature is high and the loading givesrise to high forces and mornents. In fact, thepermafrost temperature varies with time, dependingon the air temperature and the chilling effect ofbasements, channels, and thermopiles. Pile loadingsalso vary with time, being law during theperiod of construction and susceptible to transientforces, in particular those of climatic origin(snow, wind, soil heaving). All in all, maximumloading is never timed to occur simultaneouslywith the soil's minimum bearing capacity. For example,loads due to snow, wind, and soil heavingare at the maximum in autumn and winter, whereasthe soil has a minimum bearing capacity in summer.This fact is of particular importance in designinglight engineering structures (pipelines, flyovers,power lines) and buildings of light-weight materialwhere transient loads account for a significantfraction of the total loading sustained.Sone design methods consider simultaneouslyloading, soil temperatures, the long-term strengthof eo11 and soil settlement, all varying withtimePiles for Use in Specific Permafrost ConditionsMethods have been developed for designing anddriving piles in ice-rich ground, subtesraneanice, saline permafrost, and thawing ground. Atthe sites where permafrost-thawing techniques areused, preference is coTnly given to staggeredpiles of considerable length and to molded-inplacepiles. Floating piles find application inconjunction with local pre-thawing of permafrost,which is then compacted as the pile is driven intoplace.PILE TESTING PROCEDURESLaboratory tests based on the kinetic theoryof strength have revealed the influence of thesize of the pile model on the adfreeze strength.4 method of allowing for this scale factor hasbeen developed.#Field tests of piles are performed at alllarge construction sites, and a standard procedurehas been established in this connection.A novel accelerated test technique has beendeveloped that relies on a "dynamowtric" apparatusas a means of applying load to the pile. Aninitial stress set in the gauge decreases with thesinking of the pile into the soil. The stress recordedwhen no further settlement of the pile isevident is adopted as the long-term ultimatestress.IMPROVING DURABILITY OF REINFORCED CONCRETE PILESThe extreme conditions of temperature and humidityin the Arctic, where temperature variationsand recurrent seasonal freezing and thawing of thesurface layer cause the high moisture content ofconcrete and freeze and thaw water in the voids ofthe concrete, have an adverse effect on reinforcedconcrete piles. Means are available to preventthe low-temperature destruction of concrete thatextend the service life of reinforced concretepiles.RESEARCH PROGRAMme following problem require further attention:- Improving the techniques of pile driving inpermafrost (especially coarse fragmental perma-frost);- Producing piles of advanced construction;- Streamlining the techniques of emplacingmolded piles;- Widening the field of application of pileswith pre-thawing of permafrost;- Improving the durability of reinforced concretepiles;- Streamlining methods fox computing thebearing power of piles (compiling new tables, constructingnew alignment charts, etc.);- Developing a single methodology of piletesting to be recommended for use in all countries;- Collecting a wealth of experirnental data onthe strength of freezing and the bearing power ofpiles under various conditions with an eye to providingdesign criteria for practical use on analyzingthese data (achievable if researchers fromall countries pool their efforts).

STUDY AND PRACTICE ON DEEP FOUNDATIONS IN PERMAFROST AREAS OF CHINADing JinkangNorthwest InstituteLanzhou, People's Republic of ChinaIn China permafrost occupies an area of about2,150,000 km2, covering almost 22% of the territoryof the country. The high mountainous regionsof the Qinghai-Xizang Plateau, the Tian Shan Mountains,the Great Xing'an Mountains, the QilianMountains, and the Altai Mountains are the primaryregions where permafrost exists. Among these,permfrost in the Qinghai-Xizang Plateau is themost highly developed, with the highest elevation,the most wide-spread area, the deepest layer, andthe lowest temperatures, as compared to the lowlatituderegions of the world. The Plateau has anarea of about 1,490,000 km2, which is almost 70%of the total permafrost area of China.Since liberation, with the exploitation andutilization of the forest resources of the GreatXing'an Mountains and the development of such borderlandsas Qinghai and Xizang, the Ya-Lin, Nen-Lin, and Chao-Wu railroads have been constructedin the permafrost area of the Great Xing'an Mountains,and highwayo have spread throughout theforests of the region. The highway linking Ge'rmuin Qinghai Province and Lhasa in Xizang has beenconstructed, crossing a pertmfroat belt of morethan 600 km. To develop the Reshui and Siangcangcoal mines in the permafrost region of the QilianMountains, railroads and highways were built andmining and residential areas were established. Inaddition, an oil pipeline was constructed fromGel- to Lhasa in the 1970s. Al these projectshave accelerated the study and development inChina of foundations in permafrost areas.In early construction projects, conventionalmethods used in temperate regions for surveyingand designing ground foundations were used due tolack of knowledge about permafrost. AB a result,deterioration and even destruction frequently occurredduring operation. The most serious problemsoccurred in building construction; somebuildings had to be built over and over again dueto frost-heaving and thawing settlement. We wereforced to consider carefully and thoroughly thespecific features of foundations in permafrostareas and to inquire into suitable forum of foundations.In the early 19608, a series of tests weremade on piles, which at that time were used as thebuilding foundations in permafrost areas. Explosion-expandedpile foundations (Figure 1) werefirst tested in the permafrost region of the GreatXing'an Mountains (TSDI, 1976a,b) on a 1.4-km watersupply pipeline built in 1967 and an inhabitedhouse. The pipeline was an overhead one supportedby 340 explosion-expanded piles, each 40 cm in diameterand buried to a depth of 2.5 m. Under operation,it was found that the frost table underthe gravel soil was relatively deeper and the burialdepth of the explosion-expanded piles was aFIGURE 11 Bearing platform"" . hf"Extended end of pileExplosion-expanded pile foundation.little shallower; this caused serious frost heavingand led to the deformation of the pipeline.Within the sector of clayey soil, however, wherepiles were buried in permafrost to depths of 1-3rn, no frost heaving took place. The Eoundationof the tested house consisted of seven 25-cm-diareter piles buried to a depth of 2 m in permafrost.The wide end of each pile was 60 cm in diameter.No significant frost-heaving was observed.Despite deficiencies and incompleteness,the tests did provide valuable experience in designingand constructing explosion-expanding pilefoundations.Further experiments were made on explosionexpandingpile foundations €or buildings, bridges,and culverts built in the Great Xing'an Mountainsand on the Qinghai-Xizang Plateau in the early1970s (TSDI, 1971; Ma, 1981). The dirnsions andburial depth of piles as wel as the constructiontechnology used were changed and improved. Forinstance, 30-cm-diameter explosion-expanded piles,buried at depths of 4-5 m with an 80-cm-diameterwidened end were used in house construction, andpiles of 35 cm diameter burled to 4-5.5 m wereadopted in culvert engineering. The constructionnethod was to drill first and then use explosionsto shape borings and the widened ends to the specifications.Al houses and culverts built duringthis time have operated normally so far.Inserted and poured piles were used in highwayengineering in permafrost areas (Figures 2 and3) in the middle of the 1960s. The diameter andburial depth of poured piles ranged from 50-125 cmand 8-10 m respectively. For inserted piles, hollclwreinforced concrete piles with a 70-cm diameterand a 5-em shell were used. After the pilewas inserted in the borehole, concrete was pouredinto the hollow center, and clay mortar was poured18

19I/Bearing platformFIGURE 2Inserted pile foundation.FIGURE 3Poured pile foundation.around the pile. The burial depth was 8-10 m.During this period, these piles were used in abaut50 large and middle-sized bridges. No obvious deformationhas been found since they were completed,and they are still in regular operation.The successful use of bored piles in highwaybridge engineering was folluwed by their trial applicationto house building in the early 1970s.The loading characteristics of various kinds ofbored piles were studied to acquire data for designingfoundations with them. 'pwo sectors in theQinghai-Xizang Plateau with differing featureswere chosen as the test sites. Vertical and horizontalloading tests of inserted, driven, andpoured piles were made (NICARS, 1977). Based onthe results, a test house with an inserted-pilefoundation and an engineering production buildingwith a driven-pile foundation were constructed onthe Plateau (FSDI, 1978). The former was theboiler room and kitchen of the Frost Research Stationand the latter was the water tauer, boilerroom and puap house, and electrical machinery roomof a pump station. Hollow reinforced concretepiles were used at both sites; they had a diameterof 40 cm, were buried to a depth of 6 m, and ventilationwas applied to keep the ground frozen.The lmilding was completed in 1977 and no obviousdeforrmtion has yet been discovered.Meanwhile, two test houses with poured-pilefoundations -- the residences of the Frost ResearchStation -- were designed by the JingtaoFrost Station, located in the pernufrost region ofthe Great Xing'an Mountains (He and Xiao, 1981).A raised foundation was not used in this case, usingthe thawing disc of ground to keep the basetemperature inside the hildings as constant aspossible. Because of the required maximum computedthawing depth of the disc and the Boil bearingcapacity, the designed pile diameter and burialdepth were 26 cm and 7.5 m respectively. 'She twobuildings were completed in 1976, and observationsand tests verify that the strength of the concreteand the bearing capacity of the piles all met thedesign specifications.IBearing platformFIGURE 4 Buried pile foundation.While bored-pile foundations were tested andput into use, experiments on other types of deepfoundations were atarted in various petmeErostareas. For instance, buried-pile foundations weretested in house construction in the permfrost regionof the Great Xing'an Mountains (Qiqiha'rRailway Mmin., 1975; Wang, 1982). The pile foundationwas composed of prefabricated, reinforcedconcrete pillars (or rock pillars with mortar),ring-shaped base (or widened base), and bearingplatform (Figure 4). The construction was carriedart in sequence as follms:1) Excavate the foundation pit.2) kry the base.3) Put the piles vertically on the base.4) Refill the pit.5) Pour in concrete to cast the bearing platform.The tests were conducted at two separatesites; at one a raised foundation was constructedto provide natural ventilation to prevent theground from thawing. The section of pile was 20 x

2020 cm, that of the base was 110 x 110 cm, and theburial depth was 3.35 m. At the other site, thefoundation was not raised, Le. ground soil waspermitted to thaw. The section of pile was 25 x25 cm, that of the base was 75 X 75 cm, and theburial depth was 5.5 m. The two houses were completedin 1974 and 1976, respectively. Observationsshowed that the maximum thawing depth of theformer was 2.1 m, while that of the latter was 5.6m. Cracks and deformation appeared in both housesdue to insufficient burial depths.Buried-pile foundations with ventilation werealso used to build the electrical machinery room,oil pump house, and boiler room of an oil pumpstation on the Qinghai-Xizang Plateau in 1976.The burial depth of the piles was 5 m. No evidentdeformation has occurred since the completion ofconstruction, demonstrating that this type offoundation is successful.Another type, the so-called "deep mss foundation,"had a dimension of 30.5 x 18 x 1.2 m andwas buried to a depth of 6 m. It was used in thedesign of the coal storehouse of the Reshul coalmines in the Qilian Mountain permafrost region(Qinghai Design Inst. of Mines, 1978). The storehousewas completed and put into use in 1978 andthe deformation has not yet exceeded permissiblevalues.Through these investigations and experience,poured, inserted, and buried pile foundations haverecently come into general use in China in the engineeringof railroad and highway bridges, as wellas house construction, in permafrost areas. Theuse of deep foundations has thoroughly transformedthe unstability of building in these areas, and ithas greatly improved the confidence of engineering.It can be stated without a doubt that the1980s will be years characterized by the generaluse of deep foundations in China's permafrostareas.Since the 1970s our researchers have been investigatingthe problem of designing deep foundationsfor permafrost areas. The major problemsinclude: the bearing characteristics of piles inpermafrost, methods €or computing the resistantfrost-heaving stability of piles, ways to protectpile foundations from frost heave, and calculatingthe stability of the thaw disc beneath heatedbuildings. This research has extended the use ofdeep foundations. What follows is a brief introductionto 8om of our results.BEARING CHARACTERISTICS OF PILE I N PERMAFROSTThe bearing characteristics of a pile in permafrostdepend upon the nature of the permafrostand the freezing properties of the boundary surfacebetween it and the pile. The vertical bearingcapacity of the pile involves the boundary adfreezingforce and the reaction force at the pileend. The major bearing capacity depends on theformer. The magnitude of the adfreezing force relatesnot only to the soil properties (water contentand permafrost temperature), but also to thematerial used, the roughness of the pile surface,and the lateral pressure acting on the pile.Loading tests have been made on frequently usedTABLE 1 The critical adfreezing strength (T/m2)of bored piles.Averagesurrounding Type of piletemperature ("C) Inserted Driven Poure-1 .o 6.0 8.7 --0.5 4.1 8.2 12.2piles, such as reinforced concrete inserted piles,driven piles, and poured piles; the results arelisted in Table 1.It can be seen from Table 1 that the adfreezingstrength of poured piles is the greatest becauseit has the roughest surface, that of drivenpiles is odium, since the lateral pressure thatacts on it is the greatest, which brings it intotight contact with the surrounding frost, and thatof inserted piles is the least of the three (PileFoundation Res. Gp., 1978).Other tests showed that while a pile is settlingunder external force, a reaction force appearsat its bottom end, which increases with theexternal load. The magnitude of the reaction varieswith the testing method, the load, and thepile type. For example, the reaction force undercritical load appropriates 20% and 10% of the loadfor driven and poured reinforced concrete piles,respectively (Cheng et al., 1981).The bearing capacity of a single verticalpile in frost is calculated by the following equation(NICARS, 1977):whereP - the permitted bearing force forpile, TK - coefficient of safetya singleri - the critical long-term and freezingstrength between frost layer i and thelateral surface of the pile, T/m2Fi - the freezing area between frost layer iand the lateral surface of the pile, m2Q - the decreasing coefficient of the bottom-endsupporting capacity of the pileA - the top-end supportingR - the permissible bearing capacityfrost beneath the pile, T/m2area of the pileof theThe value of m, has something to do withcleaning up the bottom of the hole. It is recommended,under ordinary circumtances, that 0.5-0.9be adequate.The above equation is basically similar tothat being used by the frost engineering circle.Both equations suggest that bearing capacity is

21cmc.-0 100 200 300Anchoring length, cmFIGURE 5 Resistant force of anchor-arm vs anchoringlength.directly proportional to the freezing area of thepile, Le. to the length of the pile, provided thediameter remains unchanged.In 1980, the Northwest Institute of the ChineseAcademy of Railway Sciences made a series oftests on the resistance force of anchors in thepermafrost region of the Qinghai-Xizang Plateau.Reinforced concrete anchors of 10 cm in diameterwere adopted with burial depths of 2-4 m. Testresults showed that the relationship between theresistant force and the length of the anchor tendedto be nonlinear as the anchor reached a certainvalue (Figure 5) (Ding, 1981a). That is to say,there is no direct ratio between the resistantforce of the anchor and its length.The specific bearing capacity of the anchoris determined by gradual damage and the rewantadfreezing strength. The tests showed that underexternal load the distribution of shear stressalong the freezing boundary surface of the anchorwas uneven, attenuating exponentially with increasingdepth. The destruction of adfreezingstrength, therefore, does not take place simultaneouslyalong the whole boundary, but occurs at acertain point in the boundary where shear strengthhas attained a critical state. The maximum shearstress then moves downward, bringing the freezingstrength of the neighboring part to a criticalstate. This gradual destruction does not stop untilthe anchor loses its stability.However, a remnant adfreezing strength willact on the freezing boundary of the anchor even ifthe adfreezing strength as a whole is destroyed.Continually increasing the length of the anchorcan only serve to make further use of the rewantadfreezing strength, which is why the resistantforce increases slowly, presenting a clearly nonlinearproperty.Generally, the nonlinearity, as mentionedabove, occurs in the relationship between bearingcapacity and pile length if the length-to-diamzterratio of a single pile in permafrost reaches acertain value. Therefore, a revision factor ofpile length should be taken into account in theformula for computing the bearing capacity of asingle pile (Ding, 1981b).Considering these bearing characteristics, weare sure that there rmst be an optimum length fora single pile in permafrost where the average adfreezingstrength will be at the maximum. %reover,it will be the most reasonable, both economicallyand technically.The elastic foundation beam method is stillused to calculate the horizontal load of a singlepile in permafrost. After comparing results calculatedon the basis of the assumed distributionpattern of ground coefficients with the test data,we found the distribution pattern achieved by the"value K method" was most similar to the testdata; in other words, ground coefficients abovethe first elastic zero point are distributed inthe form of a concave parabola and below it thedistribution pattern with a constant is in relativeconformance with the reality of piles in permafrost(Cheng et al., 1981).REFREEZING GROUND SOIL SURROUNDING PILESThe time taken to refreeze the soil surroundingthe pile is of great importance to the designand construction of the pile. It is controlled bysuch factors as the construction method, the typeand dimension of the pile, the construction Beason,the temperature of the permafrost, and BOforth. 'Ihe refreezing tiues of ground soil surroundingdriven, inserted, and poured reinforcedconcrete piles were measured in the permafrostareas of the Qinghai-Xizang Plateau. The resultsindicated that heat introduced by driven piles wasthe least, that is, refreezing occurred in theshortest period of time, from 5-11 days after thepile had been set. The ground temperature wasdisturbed the most by heat introduced by mixed materialsalong with the heat of liquefaction ofconcrete; as a result, refreezing took as long as30-60 days. The time taken for refreezing theground soil surrounding the inserted pile lay betweenthe above two, and lasted from 6 to 15 days(NICARS, 1977).In the permafrost region of the Great Xing'anMountains, winter is usually chosen as the constructionseason to speed up the refreezing rateof the soil around poured piles. In this case,care must be taken to prevent the concrete fromfreezing and to guarantee the necessary strengthof the concrete.In the 19708, along with the use of pouredpiles for highway bridges built in permafrost regions,the study of negative-temperature concretewas initiated. To reduce the heat effect of concrete,and increase its freeze-resistant durabilityand mildness and its hardening rate at law temperature,the researchers devised a way to addchemicals to the concrete. Different types andamounts of chemicals are added according to theconstruction season, the permafrost temperature,and other design specifications so the concretewould meet the needs mentioned. Trial houseand bridge construction projects in the GreatXing'an Mountains and the Qinghai-Xizang Plateauhave proved that the strength of concrete withchemical additives can attain or surpass the designgrade regardless of the dimension of thepoured pile (RCI, 1979; Beilongjiang Microtherm

22TABLE 2 Strength of negative-temperature concrete at different stages.Compressive strengthNO. of Kind of Design grade Degree of (kg/cm2)sample sample Mixing ratio slump (cm) R7 R28 R21310 without 200chemical 0.6:1.24:3.8additives5"""--38.1 60.2 9326 with 200chemical 0.6:1.24:3.8additives80 with 200chemical 0.5:1.24:3.25additives10"141.6 207"155.6 162"17 -~-137.8 225.5102.9 152.5 163NOTE: Denominators refer to strength of 10xlOxlO cm sample placed inpermafrost. Numerators are strength of sample taken from test pile bydrilling.Res. Inst., 1979; He, 1981). In one of the tests,in the Great Xing'an Mountains, sodium nitrite andother chemicals were added to concrete and it waspoured into two boreholes with diameters of 80 cmand 26 cm at burial depths of 2 m and 5.5 m respectively.Table 2 lists the strength of theconcrete after it had been in the foundations attemperatures of -2% to -5'C for 213 days. It canbe seen that, under negative temperature, the concreteswith additional chemicals all reached orexceeded the design strength.RESEARCH ON THE FROST-HEAVE-RESISTANTSTABILITY OF FOUNDATIONSIn the course of freezing the soil mass ofthe active layer that surrounds the upper of parta deep foundation, tangential frost-heaving forceand the reaction forces will develop due to theresistance of foundation. These forces are equalin magnitude but opposite in direction. The reactionforce is of greater importance in computingfoundation stability.Tests on the reaction force were =de at asite in the Great Xing'an Mountaine in 1978. Itsdistribution pattern around the foundation isshown in Figure 6 (Cui and Zhou, 1981; HeilongjiangWater Res. Inst., 1981). It can be seenthat the reaction force around the foundation appearsas a double hump, weaker near the foundation.This is because, during the course, part ofthe tangential frost-heaving force and reac- thetion force are relieved as the frost and the thawingsoil move up and down the foundation circumference.According to the theory that tangentialfrost-heaving force is equal to the reactionforce, the tangential force measured in fieldtests by rigid frame counter-compression and loadcounter-compression rmst be equivalent to the reactionforce shown in Figure 6. Here the workdissipated by friction can hardly be measured bythe methods used.FIGURE 6Ground surfaceTr heavingNov 15,1979, Nov 20,1978Distance, cmDistribution of heaving reaction.To compute the frost-heaving stability of thefoundation, the force system of stability uust beadded to the reaction force acting on the frontedge of the foundation, while to compute the tensilestrength of the foundation, the reactionforce relieved by friction mst be taken into account.The distribution of tangential frost-heavingforces along the depth of the foundation is uneven,being distributed mostly within the upper partof the active layer at a depth two-thirds of itsthickness. This can be taken as the base for calculatingthe tangential frost-heaving force whencoaputing the frost-heaving stability of thefoundation.The following conversion factors are taken todetermine the effect of foundation materials ontangential frost-heaving force: If the tangentialfrost-heaving pressure acting on the concretefoundation is 1, then that of steel is 1.66, ofrock foundation with mortar ie 1.29, and of woodis 1.06 (Ding, 1983~).

23PROTECTING PILE FOUNDATIONS FROM FROST-HEAVEThe design of the burial depth of deep foundationsin permafrost is often restricted by therequirements of frost-heaving stability. Frequently,piles mst be buried more than 2.5 tiesdeeper than the frost table to prevent pulling byfrost-heaving. Even so, in sow cases, deformationor destruction occurs because the foundationlacks the strength to resist the pulling.There are two ways to reduce the tangentialfrost-heaving pressure acting on foundation surfaces.One way is to reduce the foundation material'ssusceptibility to water, to weaken ice cementingbetween the frost and the foundation; theother is to improve the soil body around the foundationto reduce frost heave.A number of tests to reduce the tangentialfrost-heaving force on pile foundations have beenconducted in the permafrost areas of the Qinghai-Xizang Plateau. In the tests, residuum and anionsurface active agents were used to treat foundationscomprehensively to met the defined requirerents.The process was carried out in this way:First, the foundation surface was daubed with athin layer of residuum to change its hydraulicproperty, then certain parts of the soil surroundingpiles were treated with active agents to reducefrost heave. This method reduced 95% or soof tangential frost-heaving pressure. After acouple of freeze-thaw cycles, no clear rise intangential frost-heaPlng pressure was observed,and the stability has remained sound (Ding et al.,1982). This achieveraent was obtained in both laboratoryand field model tests. Its effectivenessand durability remain to be verified in practicalprojects.Problem still exist in design, construction,and use of deep foundations in permafrost regionsthat need further investigation and resolution:1. Providing exact adfreezing strength is thekey to correctly designing pile foundations: Bytests, we see that there is a peak value and aremnant value of adfreering strength. The averageadfreezing strength used to design pile foundationsrelates not only to the constituents ofsoil, water content, ground temperature, and pilematerial, tut also to the length and diamter ofthe pile. Of these, Khe first four factors influencepeak and remnant adfreezing strength. Therefore,studying the strengths and making use ofthem along with the length and diameter of thepile to compute average freezing strength willgive accurate parameters for computing adfreezingstrength.2. The rational distribution pattern of frostground coefficients and the values of ground coefficientsunder different frost conditions.3. The relationship between the bearingstrength at the pile end and the adfreezingstrength of the pile circumference: Although variousrthods of computing the bearing capacity ofpiles proposed in the past took into account thereaction force at the pile end, the action raechanismwhen both the pile end and the circumferenceare under load at the sa= time has not been fullyillustrated.4. The reasonable interval between piles, andtests and computions of pile groups.5. The reasonable burial depth of buried-pilefoundations: Buried-pile foundations are conparativelypopular in China owing to their simple construction,the easy treatmnt to prevent frostheave,and the low cost. It has been observed inearlier projects, however, that the annual variationof ground temperature for shallowly buriedpile foundations is considerable, yielding frostcreep as well as frost heave, which tends to causedeformation of the foundation. To prevent or reducedeformation, an allowable maximum temperaturevariation in the frost beneath such foundationsseem to be inevitable.6. Loading tests on pile foundations in permafrost:The step-by-step loading method currentlyused has some disadvantages, such as long testingtime and considerable variations of boundaryconditions. In addition, the criterion taken fordeformation stability (0.3-0.5 m/24 hr) lackssufficient scientific support. Therefore, a methodthat not only reflects the varying characteristicsof frost but also shortens testing ti= willbe the goal of further study.REFERENCESChen Xiaobai, Tong Boliang, Ding Jinkang, and ZhouChanqing, 1979, Thirty years' study and engineeringpractice on frost in China: Journalof Glaciology and Cryopedology, V. 1, no. 2.Cheng Zhohuai, Le Guoliang, Zhao Xisheng, and WangHuaqirig, 1981, Study on vertical and horizontalloading of pile foundation in permfrostarea: Northwest Institute of China Academyof Railway Sciences.Cui Chenghan, and Zhou Laijong, 1981, Study of reactionforce against frost heave: Third Surveyand Design Institute of China RailwayMinistry.Ding Jinkang, 1981a, Study on the long-term resistantforce of anchor-arm in permafrost area:Northwest Institute of China Academy of RailwaySciences.Ding Jinkang, 1981b, Study and test of severalfrost-mechanical problems.Ding Jinkang, 1983, Outdoor experimental researchon tangential frost-heaving force, Proceedingsof the Second National Conference onPermafrost, Lanzhou (1981): Lanehou, GansuPeople's Publishing House, p. 251-256.Ding Jinkang, Zhang Luxin, Ye Cheng, Yan Jingshanand Yu Changhua, 1982, Physical and chemicalmthods for decreasing the force of tangentialfrost-heave, Proceedings of the Symposiumon Glaciology and Cryopedology held bythe Geographical Society of China (Cryopedology),Lanzhou (1978): Beijing, Science PublishingHouse, p. 204-206.FSDI (First Survey and Design Institute of ChinaRailway Ministry), 1978, Report of study onhouse building in permafrost area of Qinghai--Xirang Plateau: Northwest Institute ofChina Academy of Railway Sciences.He Changgen, 1981, Test and study on poured-innegative temperature concrete in permafrost:Third Survey and Design Institute of ChinaRailway Ministry.

24He Changgeng and Xiao Youming, 1981, Test andstudy of house foundations in permafrostareas: Third Survey and Design Institute ofChina Railway Ministry.Heilongjiang Microtherm Research Institute, 1979,Test and study on poured-in pile foundationof negative temperature concrete in permafrostarea.Heilongjiang Water Research Institute, 1981, Studyon reaction force against frost heave andself-anchoring of pile foundation in seasonalfrost region.Ma Zonglong, 1981, Study of explosion-expandingpile foundations in permafrost region ofQinghai-Xizang Plateau: Northwest Instituteof China Academy of Railway Sciences.NICARS (Northwest Institute of China Academy ofRailway Sciences), 1977, Test and study ofpile foundations in permafrost areas: FirstSurvey and Design Institute of China RailwayMinistry.Qinghai Design Institute of Mines, 1978, Preliminarysummary of construction and design inReshui permafrost region.Qiqiha'r Railway Administration Scientific andTechnical Institute, 1975, A research reportof the application of pile foundation andoverhead ventilation foundation to trialbuildings in Mangui permafrost region.RCI (Railroad Construction Institute of ChinaAcademy of Railway Sciences), 1979, Technicalspecifications for designing and constructingbridges and culverts in permafrost regions ofQinghai-Xlzang Plateau.Research Group on Pile Foundations in Permafrost,1978, Testing of pile foundations in permafrostareas, Proceedings of the Third InternationalConference on Permafrost, Edmonton:Ottawa, National Research Council ofCanada, v. 2, p. 179-185.TSDI (Third Survey and Design Institute of ChinaRailway Ministry), 1971, The application ofexplosion-expanding pile foundation to bridgeand culvert engineering in severe cold andpermafrost areas.TSDI (Third Survey and Design Institute of ChinaRailway Ministry), 1976a, Experience and lessonfrom erecting pipeline in permafrost areawith explosion-expanded piles.TSDX (Third Survey and Design Institute of ChinaRailway Ministry), 1976b, A short summary onbuildings of explosion-expanded pile foundationsin De'rbur permafrost region,Wang Jianfu, 1982, Specific features of groundtemperature field of buildings furnished withheating in permafrost areas.

D.C.EschAlaska Departmentof Transportation and Public FacilitiesFairbanks, Alaska, USAThis review presents a summary of currentpractice, research efforts, and major researchneeds relating to road and railway embankments overpermafrost, with emphasis on North Americanwork. The stages of preliminary investigations,design, construction, and operation and maintenanceof road and rail embankraents are discussed insequence. Embankments for roads and railroadsnecessarily encounter a wide variety of terraintypes and permafrost conditions, and routings canseldom be selected to avoid all potential permafrostproblem areas, due to origin and destinationconstraints. Because of the great distances coveredby these facilities, subsurface informationon any single permafrost unit is normally inadequateto predict accurately embankment performance.Embankments are therefore usually constructedwithout use of any intensive permafrostrelateddesign analysis. Most engineering analysesare made only in the course of repair or reconstructionof the most severe post-constructionproblem areas. Road and railway embankment movementproblem resulting from underlying permafrostare almost always of the chronic, long-term type,so the true economic consequences of inadequatedesign and construction practices are seldom ifever known.CURRENT PRACTICEPreliminary InvestigationsAirphoto and geologic interpretations of subsurfaceconditions from surface features, withborings at intervals, are heavily relied upon inthe route selection and subsurface investigationplanning stages for roads and railways, but geophysicaldetection methods based on electromagneticand radar soundings are currently under development.Theory and practice in geophysical detectionof subsurface conditions are wel developedin the mining and petroleum industries, but thesetechnologies have not been readily adaptable toapplication by transportation engineers and geologists.There is considerable interest and hope,however, that these wthods will provide the geologistwith a new low-cost source of Subsurface informationon which to base his field boring andsampling program and even the preliminary routeselection.At the Fourth International Conference onPermafrost, 11 papers in the areas of remote sensingand geophysical sounding for the detection,mapping, and evaluation of permafrost terrain werepresented. In view of the extreme variability ofsubsurface permafrost conditions, such as ice contentsand active layer thicknesses, research isbadly needed to speed the development of new wthodsof remotely detecting subsurface conditionsthat affect embankment performance. Informationon the variability of soils and permafrost isneeded on a continuous basis along a proposed roador rail route to predict the thermal and physicalstability of alternative embankmnt designs.Design ofEmbankmentsCurrent design practice is not developedenough to predict distortions, ride roughness,travel speed, or maintenance costs related to alternativeembankment designs. Engineers have generallyadopted a negative view of such design featuresas insulation layers or passive heat-exchangesystems, although the much higher initialcosts will result in improved long-term performance.Unfortunately, researchers have not yet definedthe overall life-cycle economics of suchfeatures. Insulation is not commonly used or evenconsidered except under extreme arctic conditions,where shortages of gravel result in a direct savingsin construction costs, such as the Alaska oilpipeline workpad (Wellman et al., 1976) of whichabout 112 km (70 mi) were designed and constructedas insulated embankments.Simple and functional two- and three-dimensionalthermal. analysis methods, which would permitdesigners to analyze the long-term stabilityof alternative embankment designs, are not yetreadily available, although there is considerableresearch activity in the area of thermal modeling.The "modified Berggren" calculation method is mostcommonly used for simple, one-dimensional, singleyearthermal predictions.Heat exchange of the embankment surface ishandled by use of the simplified "n-factor" approachin design calculations. This factor, whichis the ratio of surface to air temperature freezingor thawing indices, appears to be quite usefulfor analysis of paved surfaces where evaporativeor latent heat exchange is a minor factor. N-factors€or many different surfaces have been determined(Lunardini, 1978). Surface albedo, solarexposure, and wind effects are primary conslderationsin selection of an appropriate n-factor fora given site. The importance of traffic-generatedwind effects and surface abrasion on the n-factorhave been demonstrated (Berg and Esch, 1983).Embankment slopes present a much more difficultsurface temperature simulation problem thanlevel paved surfaces. Ideally the effects of sunand slope angles, wind, snow cover, vegetationcover, evapotranspiration, and shading by adjacenttrees and brush should all be taken into accountin selection of a proper n-factor. A full energybalance approach should perhaps be attempted.25

26Hwever, errors in the assumptions needed for anexact energy balance may becolne cumulative andlead to a large error in the end result (Goodrich,1982).Embankment shape considerations and their effecton embankment performance on warm permafrosthave been studied by Esch (1978, 1983). Lateralberms, termed "thermal stabilizing berms," havebeen used extensively in Alaska in recent years,but their long-term benefits have not yet beendemonstrated to justify the construction cost, exceptwhen used as waste-disposal areas. Berm resultin a greater width of terrain disturbance andincreased slope areas that have higher averagesurface temperatures than undisturbed forest ortundra. Therefore, the berm' benefit of increasedinsulation value over permafrost rmst beweighed against the increased heat intake of theentire embankment structure. For warm permafrostareas, sow form of passive cooling system appearsnecessary, such as air or liquid convection pipesor two-phase "heat pipes," to increase wintertimeremoval of the heat that accumulates beneath embanklnentslopes and is trapped by the snow cover.Embankment reinforcement, to reduce slopemovements and to bridge smaller thermokarst pits.is currently a very active embankment design andresearch work area in Alaska. By installing multiplehorizontal layers of selected "engineeringfabrics" during construction, a more crack- andsag-free embankment may be possible. The abilityof different fabrics to span voids of differentwidths under embankment and wheel loadings (Kinney,1981) will be evaluated by field tests in1984. To date, fabrics appear to show the rmstpromise in eliminating the hazardous longitudinalembankment cracking that results from side-slopesettlements and lateral spreading. The use ofstiffer plastic mesh or steel reinforcement mayprove even more beneficial as an embankment reinforceuwnt.Design theory and calculation methods€or predicting and analyzing the performance offabric reinforced sections rmst still be developedand tested. Answers rmst also be developed toquestions regarding the necessary extent of fabriclapping or sewing and the importance of preliminaryfabric tensioning and fabric stiffness onperformance.Insulation of roadway embankments with foamedplastics to prevent thawing of underlying ice-richpermfrost has essentially remained in the experimentaldesign stage since the first installationsin 1969 (Esch, 1973). Hwever, several airfieldinsulation projects have been successfully completed.Field studies have demonstrated thatpolyurethanes and sulfur foams lack the durabilityand moisture resistance for direct burial uses underwheel loadings and high water tables. Extrudedexpanded polystyrene foam insulations, in contrast,have generally proven very durable underthese conditions. Economic Considerations andconcerns about differential surface frost formationon pavements over insulated areas have bothacted to retard the use of insulation except forcertain remote areas where gravel costs and otherconsiderations have dictated the use of foam insulation.Recent competition in the production oflow-cost, high-quality polystyrene foam insulationand developments in pavement surfaces that provideice control, such as "Verglimit" and "Plus-Ride,"should encourage increased use of embankment insulation.Pavelnent design practice €or roadways on permafrostis not significantly different from thatfor roadways in seasonal frost areas. The AlaskaDepartment of Transportation has recently completeda major research study of pavement structureperformance that evaluated pavement failures byflexural fatigue and rutting (McHattie et al.,1980). The presence of permfrost in the subgradewas not found to be a significant factor in performance.This is reasonable in view of the factthat vehicle wheel load stresses are carried almostentirely by the uppermost l m (3.3 ft) of theembankment, whereas the permafrost table is commonlyat a depth of 2 to 4 m beneath the pavement.Paveraent structures, defined as the load-carryingportion of an embankment, are therefore always includedin the "seasonal frost" zone. The onlyspecial pavement design consideration applied forpermafrost areas involves the use of a shorteneddesign life period for pavements that are expectedto be distorted severely by thaw settlements withina few years of new embankment construction.Thaw-settleent and frost-heaving problemr arerecognized and treated separately from pavementdesign considerations.Embankment ConstructionEmbanklnents on permafrost are only rarelyconstructed in winter, except perhaps on the ArcticSlope. The major questions to be resolved relateto the compaction levels attainable with frozensoils and the detrimental effects of reducedsoil-density levels and possibly trapped snow andice layers on long-term performance. Coarsegrainedsoils are more amenable to compactionwhile in a frozen state and are less inclined toloss of strength upon thawing. Specificationsthat perndt placement of certain frozen soil androck types in winter could be developed.Some performance aspects of winter versussummer construction of insulated embankments wereinvestigated by constructing two adjacent testsections near Inuvik in 1972 (Johnston. 1983).Observations through 1978 showed little differencein performance due to the timing of construction.Construction timing specifications have been usedsuccessfully in Alaska for controlling constructionof insulated road sections and for excavatingfrozen soils. Insulation placement is specifiedat the start of the thawing season, following surfacepreparation and snow-removal during the previouswinter, to assure the lowest possible subsurfacetemperature. Benefits may result from constructiontiming specifications that require a 4-month period for prethawing and consolidation ofice-rich permafrost soils before embankment placement.These benefits have been analyzed at testsites (Esch, 1982) but this approach has not yetbeen used on a construction project.An embankment was constructed on top of amechanically placed layer of frozen peat in 1973at a roadway site 80 km southeast of Fairbanks,Alaska. After an initial thaw stabilization period.the performance of this embankment has beenexcellent, and the thermal benefits of peat in the

27active layer beneath the roadway have been significant(McHattie, 1983). The great increase in thethermal conductivity of the peat upon freezing hasresulted in louer average subsurface temperaturesand preservation of the underlying permafrost. Bycomparison, the permafrost foundation of the adjacentnormal roadway section has experienced annuallyincreasing thawing, settlements, and degradation.Standard construction practice in ice-richpermafrost requires preserving the surface vegetationmat to serve as an insulation layer, a filtermedium, and a soil-reinforcing layer during andafter construction. Machine-mulching or shreddingof trees and brush with a wheeled machine, calleda "hydro-axe," is commonly used in preference tohand-clearing. However, to avoid surface damagethis machine work rmst be performed when the .ground surface is frozen.Maintenance of EmbankmentsErrors in embankment design and constructionbecorne the responsibility of the maintenance englneer.Sinkholes, sags in grades, longitudinalcracking, shoulder rotation and slumping, and culvertdistortions and blockages are commn manifestationsof embankment instability caused by thawingpermafrost. Sinks, sags, and shoulder 6lump8in paved road surfaces are routinely filled withasphalt patching material, with repairs requiredseveral times a year in the worst problem areas.For railroads, the railo mst be shimrned periodicallyand eventually the ties lifted and ballastadded to maintain grade where thaw-instability andsettlement problems occur. By comparison, thefrequent regradiggs perforroed on well travelledgravel road surfaces normally obliterate all sagsand cracks. The extent of permafrost problem ongravel roads is not normally apparent.Experiental installations of two-phase heatpipes to stabilize sinkholes in embankments havebeen made in Manitoba on the Hudson Bay Railroad(Hayley et al., 19831, and in Alaska on FarmersLoop Road near Fairbanks and at Bethel Airport.This new technology m y prove very useful, as heatpipes can be installed by slant drilling to reachbeneath areas that nust remain open to traffic.Maintaining drainage is often a major problemfor embankments on permafrost. Culvert icing oraufeis problem may require almost daily effortsat steam thawing to maintain drainage. Methods incommon use include steam discharge or hot watercycling through culvert thaw pipes, and temporarywelder or permanent powerline connection to electricthaw wires located inside the culverts. Testinstallations of solar collectors and PUTS havebeen made in Anchorage and Fairbanks, Alaska(Zarling and Miller, 1981) to thaw culverts automatically.This approach shows promise only forthose areas where springtirne ice buildup is themajor problem. The construction of insulated subdrainagesystem to intercept seepage water beforeit can reach the surface and freeze has done mchto eliminate icing problem following new embankmentconstruction (Livingston and Johnson, 1978).RESEARCH EFFORTSPermafrost area embankment monitoring inNorth Aerica was started in 1953, with the instrumentationof five roadway sections near Elenallen,Alaska. Observations at these sites consistedof continuously recorded air and pavementtemperatures and monthly observations of subsurfacetemperatures from thermistor strings. Thestability of the early thermistors used cast somedoubt on the long-term subsurface temperatures,and data reporting from these sites was minimal.FIGURE 1 Experilaental embankment monitoring Site6 on permafrost in North Amrica.refer to sites listed In Table 1.Numbers

28TABLE 1Experimental embankments on permafrost in North America.Figure I Perlodreference mnitored Site description PurposeI 1953-60Glenallen Area, AlaskaPaved roadway embankmentsDetermine air and surfacetemperatures and thermal regimein normal road embankments.Brewer et al., 19652 1969-83 Chitina. AlaskaInsulated gravel roadembankwnt, polystyrenef om3 1972-784 1973-83Mackenzie key., Inuvik,N.W.T, Polystyrene foaminsulated gravel roadembankmentRichardson Highway, Alaskaac Canyon Creek. Peatunderlay placed beneathpaved road in cut areaCompare 5 and 10 cm thickinsulation layers with adjacentnormal embankmants by air andsurface temperatures, thermalregime, and embankment settlemnts.Six road test sites with 3insulation thicknesses (5, 9, and11.5 cm) and winter and summerconstruction were compared byground temperatures and settlemnts.Evaluate benefits of placing 0.5 -0.8 m of peat in active layerbeneath road, by temperatures andsettlements.Errch, 1973Johnston, 1983Esch, 1978McHattie, 19835 1974-76Dempster my., N. W.T.10 cm foamd sulfur insulationbeneath gravel roadEvaluate performance of foamedsulfur as road insulation.Baymont. 19786 1975-83Parks My., near FairbanksAlder Creek insulated pavedroad cuts and Bonanza Creekexperimental embankmentCompare benefits of insulation at1.2 and 3.0 m depths, and analyzebenefits of toe berms, toe insulationand air-cooling ducts on slopestability of 7-m high embankment.Esch, 1978, 19637 1975-78Yukon River to Prudhoe Bay,AK Pipeline Haul Road (Daltonhy.) Gravel surfacedroadway.Evaluate the thermal regim beneatheelected normal roadway embanklqentsections in discontinuous andcontinuous perrmfrost areas.Brown and Berg, 19808 1975-83Alaska Railroad, 50 km westof Fairbank6, insulatedembankmentMonitor and evaluate the benefits ofinstalling polystyrene foaminaulatlon in a railway embankmntwith a history of permafrost thawsettlereantproblems.Trueblood,unpublished9 1978-82Hudson Bay Railway nearPort Nelson, ManitobaEvaluate the benefits of heat pipesinstetled to refreeze and stabilizepermafrost and arrest thaw-settlementproblems.Hayley , 198 310 1978-82Mackenzie Hyy. nearWrigley, N.W.T., gravelsurfaced, aeaeonal use, nosnow removalEvaluate the thermal performance ofa thin (1.2 m) embankment on warmpermafrost, including temperaturesby data-logger, thermal conductivityby probes, and settlements by levelsurveys.Goodrich, 198311 1981-83Gravel test road in palsafield along Great Whalehydro project access roadStudy probable performance andsettlement vs predictions forroad embankrent areas overlyingpalsas, a permafrost featureaurrounded by thawed makeg.Insulated and geotextile reinforcedsections Were included.Keyser and Laforte,198312 1964-83Goldstream, Moose, andSpinach Creek Bridgefoundation0 in permafrostnear FairbanksExamine the long-term thermal andphysical stability of structuresand embankments at stream crossingsCrory, 1975, 197813 1974-79Eagle River BridgeDearpeter Highway,TerritoryonYukonAnalyze the thermal effecta of bridgefoundation piles and approach embankmentfills ineulated with 10 cmof polystyrene insulation.Johnston, 198014 1969-73KotZebue AirfieldPaved and insulated runwayover permafrost,Evaluate the thermal perfomnce ofan insulated runway and an UninstIlatedtaxiway by use of a data loggerto maasure surface and subsurfacetemperatures.Esch and Rhode, 197615 1980-83Prudhoe Bay area, airport Compare temperatures around inaulat- Brown, 1983runway and roadway culvert ed and unineulated road culverts and Eaton, unpublishedmnitoring beneath Desdhorae Airfield pavement. -

29However, data did demonstrate that full annualsubroadway refreezing was occurring beneath thesepaved roadway sections in spite of the warm (-1°C)permafrost temperatures. Monitoring of thesesites was discontinued in 1960.The first insulated road embankment on permafrost,located near Chitina, Alaska, was constructedand instrumented in 1969, and has beenmonitored continually since that time, providingthe longest temperature data base for use in evaluatingthermal models. Since that time, additionalinstrumented roadway and railway embankmentshave been constructed and monitored in Alaska andCanada. Details of all such installations cannotbe given here, but Figure 1 and Table 1 shcw thelocations and references for significant experimentaldata pertinent to roads and railways overpermaf rest.Recently, three roadway sites in interiorAlaska have been painted white to masure the effectsof increased surface reflectance or albedoin reducing thaw-settlement problems. These sitesprovide a fair data base for predicting the performancebenefits of insulated embankments andother experimental features such as berms, aircoolingducts, and heat pipes, particularly inwarm permafrost. Increased field monitoring effortsare needed to masure the thermal effects ofculverts on embankmnt performance and the surfacetemperature effects of embankment slopes and slopevegetative covers, as well as the thermal stabilityof embankments overlying colder permafrost.constructed 60 years ago tends to verify this observation.Embankment drainage design considerations relatingto permafrost have not been studied in eufficient detail. So= roadway performance reportshave criticized designere for channeling flows intoculverts where cross-slope embankment routesintercept active-layer water drainage. No constructionmethods have been developed and testedthat will assure water percolation through embankmentswithout such channelization.Drainage culverts may act as embankmnt aircoolingducts or they may result in net warming,depending on seasonal air and water flows, snowcover, and so forth. Over a period of years, embanknlentsettlements and frost heaving may distortor displace culverts and make them non-functional.These therm1 aspects of culvert design have receivedessentially no research effort.A more detailed listing of research needs relatedto embankments on permafrost, recently developedby the U.S. Committee on Permafrost, istitled "Permafrost Research: An Assessment of FutureNeeds" (1983). According to this report, thehighest priority in permafrost research should begiven to developing improved methods of detectingpermafrost and ground ice and to mapping of criticalpermafrost parameters. The author shares thisview, because lack of accurate kncwledge of subsurfaceconditions prior to construction may bethe mjor problem facing the embankment designer.REFERENCESRESEARCH NEEDSBecause of the long thermal adjustuent periodthat often results from new embankment constructionover permafrost, thermal models are neededthat will economically analyze alternatives over aperiod of 20 years or more. In fact, in view ofthe forecasts of a major climatic warming trendexpected to occur in the Arctic as a result of the"greenhouse effect" due to increasing atmosphericcarbon dioxide levels, even longer periods ofthermal analysis are indicated. In areas of discontinuouspermafrost, acceleration of thawing bypreconstruction or construction operations may becomethe best design approach.Research is needed particularly to quantifythe therm1 effects of alternative embankmentside-slope surf aces and surf ace vegetation coversand to determine the role of snow-cover in embankraentperformance. Previous embankment researchstudies in discontinuous warm permafrost areashave demonstrated that progressive talik developmentbeneath snow-covered embankment slopes is amajor factor in embankment distress. Snow removalfrom roadway surfaces, by couparison, normally resultsin sufficient seasonal cooling to assure refreezingbeneath paved roadways, even in warm permafrostareas. Although railway embankments havenot been similarly instrunented and monitored, experienceIndicates that raihaya, because theylack a snow-free surface, should result in perpetualnet warming and ongoing thaw-settlement problemsin warm permafrost. Experience with continuedmaintenance on Alaska Railroad embankmntsBerg, R.L. and Esch, D.C., 1983, Effects of colorand texture on the surface temperature of asphaltconcrete pavements, & Proceedings ofthe Fourth International Conference on Permfrost,Fairbanks: Washington, D.C., NationalAcademy of Sciences, p. 57-61.Brown, J., 1983, Interaction of gravel fills, surfacedrainage, and culverts with permafrostterrain: Hanover, N.H. , U.S. Army Cold RegionsResearch and Engineering Laboratory, inpreparation.Brown, J. and Berg, R.L., eds., 1980, Environmentalengineering and ecological baseline investigationsalong the Yukon River-PrudhoeBay Haul Road: Hanover, N.H. , U. S. ArmyCold Regions Research and Engineering Laboratory,CRREL Report 80-19.Crory, PA., 1968, Bridge foundations in permafrostareas, Goldstream Creek, Fairbanks,Alaska: Hanover, N.H., U.S. Army Cold RegionsResearch and Engineering Laboratory,Technical Report 180.Crory, F.E., 1975, Bridge foundations in permafrostareas: Hanover, N.H., U.S. Army ColdRegions Research and Engineering Laboratory,Technical Report 266.Crory, F.E., 1983, Long-term foundation studies ofthree bridges in the Fairbanks area: Hanover,N.H., U.S. Army Cold Regions Researchand Engineering Laboratory, in preparation.Esch, LC., 1973, Control of permafrost degradationby roadway subgrade insulation, &Permafrost-- The North American Contribution tothe Second International Conference, Yakutsk:

30Washington, D.C., National Academy of Sciences.Esch, D.C., 1978a, Performance of a roadway with apeat underlay over permafrost: Alaska Departmentof Transportation, Research Report78-2.Esch, LC., 1978b, Road embankment design alternativesover permafrost, Proceedings of theConference on Applied Techniques for Cold Environments:New York, American Society ofCivil Engineers, p. 159-170.Esch, D.C., 1981. Thawing of permafrost by passivesolar mans, s Proceedings of theFourth Canadian Permafrost Conference,Calgary: Ottawa, National Research Council ofCanada, p. 560-569.Esch, LC., 1983, Evaluation of experimental designfactors for roadway construction overpermafrost, & Proceedings of the Fourth InternationalConference on Permafrost, Fairbanks:Washington, D. C., National Academy ofSciences, p. 283-288.Esch, D.C. and Rhode, J.J., 1977, Kotzebue Airport,runway insulation over permafrost, &Proceedings of the Second International Symposiumon Cold Regions Engineering: Fairbanks,Cold Regions Engineers ProfessionalAssociation, p. 44-61,Goodrich, L.E., 1982, An introductory review ofnurnerical rnethods €or ground therms1 regionscalculations: Ottawa, National ResearchCouncil of Canada, DBR Paper No. 1061.Goodrich, LE., 1983, Thermal performance of asection of the Mackenzie Hi.ghway, & Proceedingsof the Fourth International Conferenceon Permafrost, Fairbanks: Washington, D.C.,National Academy of Sciences, p. 353-358.Hayley, D.W., Roggensack, W., Jubien, W.E., andJohnson, P.V., 1983, Stabilization of sinkholeson the Hudson Bay Railway, * Proceedingsof the Fourth International Conferenceon Permafrost, Fairbanks: Washington, D.C.,National Academy of Sciences, p. 468-473.Johnston, G.H., 1980, Permafrost and the EagleRiver Bridge, Proceedings, Workshop onPermafrost Engineering: Ottawa, National ResearchCouncil of Canada, Technical MemorandumNo. 130.Johnston, G.H., 1983, Performance of an insulatedroadway on permafrost, Inuvik, N.W.T.,Proceedings of the Fourth International Conferenceon Permafrost, Fairbanks: Washington,D.C., National Acadeq of Sciences, p.548-553.Keyser, J.H. and Laforte, M.A., 1983, Road constructionin palsa fields: Paper given atposter session of the Fourth InternationalConference on Permafrost, Fairbanks.Kinney, T., 1981. Use of geotextiles to bridgethermokarsts: Alaska Department of Transportation,Research Report 82-21.Livingston, H. and Johnson, E., 1978, Insulatedroadway subdrains in the Subarctic €or theprevention of spring icings, in Proceeding6of the Conference on Applied Technology forCold Environments, v. 1: New York, AlnericanSociety of Civil Engineers, p. 513-521.Lunardini, V.J., 1978, Theory of N-factors andcorrelation of data, Proceedings of theThird International Conference on Permafrost,Edmonton: Ottawa, National Research Councilof Canada, p. 40-46.McHattie, R.L. and Esch, D.C., 1983, Benefits of apeat underlay used in road construction onpermafrost, Proceedings of the Fourth InternationalConference on Perafros t, Fairbanks:Washington, D.C., National Academy ofSciences, p. 826-831.&Hattie, R., Connor, B., and Esch, D.C., 1980,Pavement structure evaluation of Alaskanhighways.Raymont, M.E.D., 1978, Foaued sulfur insulationfor permafrost protection, Proceedings ofthe Third International Conference on Permfrost,Edmnton: Ottawa, National ResearchCouncil of Canada, p. 864-869.Trueblood, T., 1983, Railroad roadbed design inareas of discontinuous permafrost: AlaskaRailroad Engineering Department, report inpreparation.Wellman, J.H., Clarke, E., and Condo, A., 1976,Design and construction of synthetically insulatedgravel pads in the Alaskan Arctic, &Proceedings of the Second International Symposiumon Cold Regions Engineering: Fairbanks,University of Alaska, p. 62-85.Zarling, J. and F. Miller, 1982, Solar-assistedculvert thawing device: Alaska Department ofTransportation, Research Reports AK-RD-82-10and 83-36.

DESIGN AND PERFORMANCE OF WATER-RETAINING EMBANKMENTS IN PERMAFROSTF .H.SaylesCold Regions Research and Engineering LaboratoryHanover, New Hampshire, USA(Formerly with Office of Federal Inspector, Irvine, California,USA)To date, the water-retaining structures constructedand maintained on permafrost in NorthAmerica have been designed and built using a combinationof soil mechanics principles for unfrozensoils and unproven permafrost theory. In theUSSR. at least five sizeable hydroelectric and watersupply embankmnt dams as wel as severalamall water supply embankment dams have been constructedand maintained on permafrost, The largerdams are understood to have performed well, butthe smaller darns have been a mix of successes andfailures. (See Table 1 €or examples of problemsrecorded in the literature.) Specific criteriaare still lacking for design, operation, and postconstructionmonitoring of water-retaining embankmentsfounded on permafrost. The purpose of thispresentation is to review the current practice,point out how it is deficient, and note what majorproblems need attention.General ConsiderationsCURRENT PRACTICEIn current practice, the designs of water-rerainingembankments on permafrost can be dividedinto two general types, frozen and thawed. Thefrozen type of embankments and their foundationsare maintained frozen during the life of thestructure. The thawed type of embanklnents usuallyare designed assuming that the permafrost foundationwill thaw during either the construction orthe operation of the structure. In some locationswhere water is to be retained intermittently forshort periods of time, thawed embankments havebeen designed assuming the permafrost is to remainfrozen throughout the life of the embankment. Inselecting the type of design for a particularsite, many factors that are peculiar to cold regionsmet be considered, including:The anticipated type of service of the embankment;i.e. retain water continuouslyor only intermittently.The width, depth, temperature, and chemicalcomposition of the body of water tobe retained by the embankment.Regional and local climate conditions, especiallytemperature.The temperature of the existing permafrost.- The extent in area and depth of the permafros t.The availability of the type of earth materialsrequired for construction.The accessibility of the construction sitefor logistics involving man-made constructionmaterials.- The consequences to life and property inthe event of embankment failure.The effects of the construction and operationof the embankment on the environment.The orientation of the downstream face(i.e. the dry face) of the embankmentwith respect to solar radiation.* Frost action on the dry slopes and crestof the embankment.The economics of constructing a selecteddesign in the cold region.In addition to these rather general factors,each type of design has special requirements thatrmst be taken into account in making the final selectionof a particular design.Unfrozen Embankment on ThawingPermafrostThe design for an unfrozen embankment foundedon thawing permafrost is most suitable for siteswhere the foundation mterials are thaw-stable;Le. where the thawing strengths of the earth materialsprovide an adequate factor of safetyagainst shear failure, and deformations resultingfrom thawing will not endanger the integrity ofthe embankment. This requirement usually restrictsthe use of the thawing foundation designto sites where permafrost soil is ice-poor orwhere reasonably sound bedrock can serve as thefoundation. At sites where only a portion of thefoundation contains ice-rich permafrost at shallowdepths, this ice-rich portion is usually thawedbefore placing the embankment, or the frozen soilis excavated to a predetermined depth (Gluskin andZiskovich, 1973). MacPherson et al. (1970) suggesta method of estimating the depth of excavationso that thaw consolidation can be limited toa predetermined amount during the operation of theembankment .Where the permafrost is not removed and thefoundation is expected to thaw during the life ofthe structure, the embankment design is similar inmany respects to that of a water retaining embankmentlocated in a temperate climate. However,special consideration is given to certain elementsof the embankment. One such element is the imperviouszone, which rmst be constructed of selfhealingsoils (Gupta et al., 1973) so that thiszone can remin "impervious" even if cracking occursduring the settlement of the foundation.Soils that becow stiff and brittle when compactedin the impervious zone are avoided. Other designprovisions that are often included to accommodatethe anticipated settlement are: the use of flatterembankmnt slopes; overbuilding the height of theembankment by an amount equal to the anticipated31

32~ settlement: and aeriodica llv rebuildinn DO^ 'tionsof the embankments that setile below a tolerablelimit (Johnston, 1969; MacPherson et al., 1970).Prethawing followed by preloading to consolidatethe foundation before placement of the embankmentshas also been suggested as a means of reducingfoundation settlements (Gluskin and Ziskovich,1973). The concept of utilizing sand drains in athawing foundation to increase the rate of consolidationand, hence, quickly improve the shear resistanceand stability of embankments has beenused successfully (Johnston, 1965, 1969; MacPhersonet al., 1970), In addition, analytical methodshave been developed for estimating the ratesof thaw and settlements of dikes on permafrostduring operations using simple heat conduction andheat balance equations for a one-dimensionaltransient condition that takes into account heatfrom water seepage (Brown and Johnston, 1970).Grouting has been used successfully in coldregions to stabilize thawing foundations and tocut off seepage. At sites where the foundationmaterial is expected to be weakened or where initialseepage is expected to present a problem whenthe ice melts from the voids, the foundation areashave been thawed and grouted before the embankmentswere constructed (Gluskin et al., 1974). Asan alternative, the fissures or voids can begrouted in steps during the operational life ofthe embankment. In this case, the foundation isthawed by the heat from the impounded reservoir.As the thawing front progresses into the foundation,the fissures and voids are grouted periodically(Demidov, 1973). This method requires carefuland continuous monitoring of the thawing frontbeneath the impervious zone of the embankment.Essential elements of any thawed embankmentare the filters and drainage system for the safecontrol of seepage through and beneath the embankant.The design of these elements is similar tothose for embankments in nonpermafrost areas.However, special provisions are required to avoidplugging the drainage system with ice, which couldrender it useless at a time when it may be neededmost.Thawed Embankmenton PermafrostThe use of a thawed embankment on a nonthawingpermafrost foundation is usually limited toregions of cold permafrost where the water is tobe retained by the embankmnt for a relativelyshort period of time each year or less frequently.At these sites, artificial cooling of thefoundation may be required during construction(Rice and Simoni, 1966; Kitze and Simoni, 1972)and maybe even during the operation period. As afurther provision for keeping the foundation frozen,it is essential that a positive seepage cutoffbe provided (Borisov and Shamhura, 1959; Trupak,1970). Such a cutoff may take the form ofsheet piling, a plastic membrane (Belikov et al.,1968), or other waterproof materials that aresealed to the frozen foundation and extend up tothe embankment crest. The most economical and effectiveseepage cutoff often is a zone of frozensoil. This zone can be created from the surfacesof the embankment slopes during the winter seasonby natural freezing when water 1s not being re-ta inel d., E :f fect ive temperature and water seepagemonitoring systems are necessary in operating thistype of water-retaining embankment in order to detectthawing that may occur that would initiate aseepage path through the embankment or in thefoundation beneath it.Frozen Embankment DesignA frozen embankment design is usually suitablefor sites where the foundation becomes unstableupon thawing to a considerable depth andfor regions where the permafrost is continuous.The most essential requirement of this type of designis that the embankment and foundation be completelyimpervious to seepage since heat fromseeping water would eventually thaw the foundation.If left unchecked, the combination of thermaland mechanical erosion (piping) could breachthe embankment.Currently, frozen embankments operating withpermanent reservoirs are located in regions wherethe mean annual temperature is -8'C or colder.Even at these temperatures, embankments 10 m ormore in height require supplemental artificialfreezing for at least part of each year to ensurethat the embankment and foundation remain frozen.In addition to the climate at the site and the embankmentheight, the lateral dimensions of an impoundedreservoir mrst be considered. With time,a deep reservoir develops a talik beneath it similarto that produced by a wide lake. The largerthe talik, the greater the risk of lateral thawingunder the embankment and of initiating seepage oratability difficulties.It has been suggested that for a frozen embankmentdesign almost any type of earth materialcan be used to construct the embankments, providedthe pores of the material are filled with ice andmass is maintained frozen during the life of thestructure (Johnston and MacPherson, 1981). It hasalso been suggested that ice be used as an imperviouscore (Tsytovich, 1973). Although these suggestionshave merit, they also can cause difficulties.A large portion of the upstream section ofan embankrnt that is required to retain a permanentreservoir and the foundation supporting itwill thaw from the heat of the reservoir. Therefore,the upstream slope can become unstable ifthis portion of the embankment is not constructedof thaw-stable materials and if provisions are notmade to accommodate the differential settlementthat can occur between the core and the upstreamshell.Spillways and water outlet control structuresfounded in permafrost require special considerationswith respect to their location and to thepreservation of permfrost (Tsytovich et al.,1972; Gluskin and Ziskovich, 1973). When thesefacilities conduct water downstream near orthrough the embankment, the heat released into thestructure by the flowing water can eventually meltthe supporting permafrost, which may result indetrimental settlement of the structure andbreaching of the seepage barrier. Table 1 revealsthat most of the problems that have been associatedwith water-retaining embankments on permafrosthave been related to seepage around and beneathoutlet structures. To avoid these problems,

33spillways and other outlet structures usually arenot located within or adjacent to ice-rich permafrostwithout special refrigeration or other measuresto preserve the earth in a frozen state.Where possible, the outlet facilities are locatedat a remote site and preferably in competent bedrock.For small dams the use of siphons and pumpshave been used to control reservoir levels (Gluskinand Ziskovich, 1973). A chute spillway elevatedabove the embankmnt surface (Bogoslovskiiet al., 1966) is one possible solution, but themost common practice is to locate the spillway inone of the abutments on bedrock and to use refrigerationor grout to control the seepage. The importanceof a positive seepage cutoff must be emphasizedbecause of the possible formation and enlargementof a talik that can grow laterally fromthe outlet works into and beneath the adjacent embankment.As a result, the entire facility can beendangered if it is a frozen-type design.Thermal AnalysisEssential to the design of water retainingembankments on permafrost is the determination ofthe thermal regime throughout the life of thestructure (Bogoslovskii, 1958; Teytovich et al..1972). A number of methods have been developedand others are being developed €or estimating thetherm1 regimes of these embankments and theirfoundations. Some of the methods currently in useinclude :a. One-dimensional analyses that are appliedat critical locations within thecross-sections of the embankment andfoundation (Tsytovich et al., 1972). Inareas where water does not change phase,simple heat-conduction equations areused in the analyses. The Stefan-Boltzmannequation or the Neumann solution tothe Fourier equation Is used to establishthe position of the freezing andthawing front. This one-dimensionalmethod can be used to analyze the transientheat flow condition.b. Hydraulic analog computers to analyzetwo-dimensional simple heat flow conditionsand to establish the location ofthe freezing or thawing front (Tsytovichet al., 1972).C. Numerical techniques, such as the finitedifferences and finite elements methods,to analyze heat flow, including changeof phase for two dimensions (Bogoslovdmskii, 1958).Physical models constructed of soil inthe laboratory to validate the analyticalmethods as wel as to simulate theprototypes for heat flaw.e. The three-dimensional finite elementmethod of analysis, which accounts forthe heat transferred by the seepage water;this is still in the developmentstage. It is especially useful €or analyzingthe special conditions at damabutments, areas adjacent to water wtletfacilities, and short dams (Bogoslovskii,1970).Of these methods, the one-dimensional analysisis now used most often, although the two-dimensionalfinite element method, which accountsfor the latent heat of fusion, is also frequentlyused.Meaningful thermal analysis requires realisticinformation for defining the thermal propertiesof soil, the initial temperature distributionwithin the soil, the geometrical and thermalboundary conditions, and, where appropriate, informationabout the amount of heat carried by theseepage water. The analysis mst also account forthe change in the thermal properties of the soildue to a change in phase (i.e. frozen or unfrozenproperties) and the change in density due to consolidationof the soil upon thawing. At a givensite, the initial soil temperature distributionoften is determined by in situ temperature measurements.Where accurate meteorological data is availablefor several years, reasonable estimates ofthe initial temperature distribution of undisturbedsites have been =de using heat balanceequations that take into account, directly or indirectly,such heat sources and losses as solarradiation, air temperature, wind velocity, evapotranspiration,geothermal gradient, and flowingground and surface water. ‘Ihe upper boundariesfor thermal analyses are usually the interfaces ofthe atmosphere with the surfaces of the embankmentand the natural ground. Some analyses considerthe surface of the snow, if it exists, as the upperboundary. In such cases, the depth and thermalproperties of the snow are required for theanalysis. The lower thermal boundary often isconsidered to be isothermal, or a constant geothermalgradient is assumed to exist at this surface.In two-dimensional analyses, the lateralboundary surfaces are usually assumed to be adiabatic.Although few details are published on thethermal analyses for artificially freezing waterretainingembankments on permafrost, the necessaryinformation is available on methods of analysisdeveloped for freezing shafts, tunnels, and wallsto exclude water and soil from excavations duringconstruction in nonpermafrost areas (Khakimov,1963; Sanger and Sayles, 1978).The efficiency with which heat passes betweenthe atmosphere and earth materials is computed byusing heat-transfer coefficients or factors. Thevalues of the heat coefficients used at the upperboundaries depend upon the color and type of surfaceexposed to the atmosphere and sun; that is,whether the surface is light or dark and whetherit is covered with gravel, atone, snow, vegetation,or other types of materials.Methods for calculating heat transfer due toseepage and the convection of water are stillquite crude, but numerical methods are being formulatedthat should eventually improve this computation(Brown and Johnston, 1970). The convectionof air within a rockfill embankment can transferlarge amounts of heat under certain conditions(Mukhetdinov, 1969; Melnikov and Olovln, 1983).Methods for analyzing convection in embankmentshave been developed and are still under development.

34StabilityIn evaluating the stability of a water-retainingembankment on permafrost, the functions ofeach zone within the embankment must be considered.Embankments designed to remain frozenthroughout their life consist of an upstreamthawed zone and a downstream frozen zone. The upstreamzone serves as a thermal insulator (Bogoslovskii,1958) to protect the downstream frozenzone from the heat of the water being retained aswell as to protect against mechanical erosion frommoving water or ice. The frozen downstream zoneprovides the impervious water barrier and resistanceto the horizontal forces exerted on the embankment.The thawing front within the upstreamzone and its foundation can be the seat of embankmentfailure when the shear resistance of the soildecreases due to development of excess pore waterpressure. This excess pressure can occur when thethawing front advances faster than the meltwatercan escape. The upstresm shell of the embankmentis especially susceptible to this type of shear orslide failure when the level of the water beingretained by the embankment is lowered rapidly. Indetermining the stability of the upstream slope,the thawing front is included in the trial failuresurfaces.The stability of unfrozen embankments on permafrostis evaluated similarly to embankments innon-permafrost areas, except that special considerationis given to the low shear resistance thatmay exist in the foundation at the thawing interfaceof the permafrost. A portion or all of thisinterface is included as part of the trial failuresurfaces that are investigated in the stabilityanalyses. The shearing resistance at this interfaceis a major consideration in assessing the resistanceto horizontal forces. To Increase theshearing resistance at the thawing front, verticalsand drains terminating in an intercepting horizontaldrainage system have been used successfully(Johnston, 1969; Gupta et al., 1973) to acceleratethe dissipation of excess pore water pressure.Maintaining the Frozen StateWater-retaining EmbankmentsTechniques for maintaining embankments in afrozen state include both natural and artificialcooling. Natural cooling is usually used forsmall embankments with heights of 10 m or lesswhere the natural cold atmosphere freezes the topand the exposed slopes of the embankment. Techniquesthat have been used or proposed to encouragenatural freezing include: removal of snowfrom the downstream face, by equipment or by constructinghorizontal wind "vanes" that direct thewind parallel to the surface of the dam and blowingsnow away from the downstream slope; placing ashelter over the downstream slope to keep snow andrain off the surface and to shade it from the sun;creating a thick snow cover on the downstream surfaceduring the early spring and providing forwinter ventilation at the embankment surface byconstructing duct work beneath the snow and ice onthis surface; protecting the downstream toe fromthe warming effect of the tailwater by usingberms; and keeping the foundation frozen duringofcons t ruc .tion (Bar,isov an d Sham Ihura. , 1959; Tsvid,1961). TsytoAch (1973) has pointed Out that thenatural cooling of soils on the downstream slopeof an embankment dam will reach a maximum depth ofabout 10 m in a severely cold climate if the surfaceis kept clear of snow. Therefore, auxiliarycooling is required if freezing is to be accomplishedat greater depths.Frozen earth dams with heights of up to about25 m have been hilt in the USSR using artificialrefrigeration. The refrigeration systems include:the circulation of natural chilled air, the circulationof artificially chilled liquid brine, andthe installation of a series of automatic thermaldevices such as thermal piles. The cooling elemntsin each of these systems consist essentiallyof vertical pipes installed along the axis of theembankment. Each pipe extends down through theembankment into the permafrost foundation. Whenair is used as a coolant, each vertical pipe has asmaller pipe located concentrically inside it.Air is circulated down the annulus between the twopipes to a point near the bottom of the outer pipewhere the air enters the inner pipe, and is returnedup to the atmosphere through an exit manifold(Biyanov and Makarov, 1978). 'Ihe air is allowedto flow through the system only when itstemperature is lower than some predetermined temperature,say abwt -15°C. Cooling by air can beused effectively at locations where the mean annualair temperature does not exceed -5'C (Trupak,1970). In regions of high humidity, rust and icecan form inside the freezing pipe, resulting inreduced heat removal efficiency and even pluggingthe pipes completely (Sereda, 1959; Gluskin andZiskovich, 1973; Biyanov and Makarov, 1978). Whenliquid brine systems are used, they consist of arefrigeration unit with a heat exchanger for coolinga heat transfer liquid or brine, which is circulatedthrough the cooling elements in the embankment.Calcium chloride solution has been usedas a brine, and in one instance the system had tobe converted to an air-cooling system when thecalcium chloride leaked into the frozen soil andmelted it (Borisov and Shamshura, 1959; Tsvetkova,1960). The cooling brine rmst not contain impuritiesor water that will deposit in the pipes andrestrict the flow of brine or plug the pipes, socorrosion inhibitors are incorporated into thebrine. In addition, the piping systems are madeof materials that resist the attack of the circulatingbrine (Borisov and Shamshura, 1959). Thermaldevices (e.g. thermal piles) that have beenused in the USSR to freeze an impervious zone in adam usually are of the single-phase gravity typethat uses kerosene as a transfer liquid (Gapeev,1967; Biyanov and Makarov, 19781, although thetwo-phase thermal device that uses ammonia as atransfer fluid is now used in the USSR. In NorthAmerica, two-phase thermal piles are used to alimited extent to maintain river levees in thefrozen state. Both the single-phase and the twophasesystems can perform satisfactorily.Embankment dams on permafrost in the USSRthat are higher than 25 m are usually designed asunfrozen rockfill dams on a thaw-stable bedrockfoundation. The temperature of the foundation ismonitored to follow the movement of the thawingfront in the foundation, and in at least one inst-

35ance cement grout is periodically injected intothe thawed zone of the foundation as the thawingfront advances in depth (Demldov, 1973). It hasbeen observed that air circulating within thedmstream rockfill section of an embankment damby natural convection has resulted in ice depositsfrom moisture condensing on the cold rock surfacesnear the downstream surface of the dam in its upperreaches, and that the foundation freezes ratherthan thaws near the downstream toe of the dam(Kamenskii, 1973). Preliminary studies (hblnikovand Olovin, 1983) indicate that cold winter airsinks through the downstream rockfill zone to thebase of this zone, where it encounters the relativelywarm, moist foundation. The air is warmedand picks up moisture at this point, then risesthrough the rockfill where the moisture is depositedon the colder rock surfaces located near thesurface of the dmstream slope. In one case, theheat removed from the foundation by this convectionhas frozen at least part of the talik (Melnikovand Olovin, 1983) that existed beneath theriver bed before the dam was constructed.Experience in Operation and ConstructionExperience in the USSR and North America hasdemonstrated that water-retaining embankments canbe constructed and successfully operated on pemfrostif appropriate precautions are taken. Inthe USSR, at least five intermediate-size embankmentdams with heights ranging from 20 to 125 m(Biyanov, 1973; Tsytovich et al., 1978; Johnsonand Sayles, 1980; Johnston and MacPherson, 1981)are now in operation on permafrost. Several smallerembankments have been functioning for manyyears. The oldest known embankment dam on permafrostwas built in 1792 at Petrovsk-Zabaykalskiyand continued in operation until 1929 without incident(Tsvetkova, 1960; Tsytovich, 1973). Manyof the smaller darns performed satisfactorily; however,some have had problems, especially in controllingthe seepage around the water outlet facilities(see Table 1).Much experimentation to develop techniquesfor creating and maintaining frozen embankments onpermafrost has been conducted in the USSR. Onepioneer project is a l0-m-high frozen dam built in1942 on the Dolgaia River at Noril'sk that was initiallycooled by circulating a calcium chloridebrine through vertical freezing pipes installedalong the centerline of the dam. These pipes extendedthrough the talik beneath the river bed.Brine leaks made it necessary to change the circulatingfluid from brine to air. The dam performedsatisfactorily; however, only after an ice sheetwas created on the downstream slope to stabilizethe thermal regime (Borisov and Shamshura, 1959;Tsvetkova, 1960).TWO water supply dams located in the IrelyakhRiver near Mirnyy, Yakutia, USSR, were built onpermafrost using innovative methods for thatarea. The older one, a temporary dam built in1957, is a 6-m-high earthfill dam with a timbercrib filled with loam serving as an imperviouscore (Lyskanov, 1964). This core extends down tothe fissured sedimentary bedrock. The spillwayconsists of a timber flume with wooden crib wingwalls. Temperature observations over a 7-yr periodof operation showed that the foundation thawedto a depth of approximately 50 m due to the flowof water through the spillway (Johnson and Sayles,1980). The average temperature of the permafrostin this area was about -2%. The second dam, completedin 1964, is a 20.7-m-high earthfill embankmentlocated about 2 km upstream from the temporarydam (Biyanov, 1966; Semenov, 1967; Smirnov andVasiliev, 1973). This main Irelyakh River dam isfounded on about 8 m of Quaternary deposits consistingof frozen sandy gravel and silty clayshaving up to 60% ice content. Beneath this depositlies fractured dolomitized limestone and marlwith ice content up to 10%. The embankment crosssection consists of a large silty clay centralsection with zones of sand beneath layers of gravelon both the upstream and downstream slopes. Asilty clay cutoff extends through the Quaternarydeposits to bedrock along the centerline of thedam.Because thawing of the ice-rich foundationsoils would cause unacceptable settlements, a lineof vertical cooling pipes was installed at 1.53spacing along the axis of the embankment to establisha positive seepage cutoff. The cooling pipeswere designed to extend d m through the embankmentand about 3 m into the foundation; however,during construction the permafrost thawed an additional6 m and the cooling pipes were consequentlyextended to this depth.After operating the cooling system the firstwinter, the dam foundation and core became almostentirely frozen along a line of laerged ice-soilcylinders that froze around each freezing pipe.Only two unfrozen sections were detected and thesebecame frozen during the second winter.To reduce the velocity of seepage from thereservoir in the talik beneath the embankment duringthe initial operation of the cooling system,an additional row of cooling pipes was installedalong the downstream toe of the dam across the oldriver bed. After the central ice-soil cylindershad merged, chilling at the downstream toe was nolonger required. Horizontal cooling pipes wereinstalled beneath the concrete spillway located onthe left abutment. To protect the adjacent embankmentfrom thawing as a result of heat from thewater discharged over the spillway, a line of verticalcooling pipes was installed along the embankmentside of the spillway discharge chute,which is paved with concrete slabs on a gravelfilter. After about 10 years of operation with apermanent reservoir, temperature measurements inthe spillway area showed that the permafrost wasthawing beneath the spillway chute toward the embankment.As a result, not only was the thawingfront advancing toward the dams, but the concreteslabs also became misaligned and moved from theiroriginal positions, thus inducing further degradationof the permafrost. To arrest this thawing,additional freezing pipes were installed and thespillway crest was raised to increase the pool capacityand thereby reduce the amount of water dischargedduring periods of high runoff (Anisimovand Sorokin, 1975).The Irelyakh River dam has had a permanentpool behind it for over 18 years, and althoughdegradation of the permafrost in the spillway areahad to be arrested, the embankroent has performedsatisfactorily as a result of proper maintenance.

36It is interesting to note that no especiallyhigh embankment dams (i.e., higher than about 50m) have been hilt on permafrost with frozen soilsas the water seepage barrier. The larger embankmentsare founded on incompressible bedrock in theUSSR (Tsytovich, 1973) and are designed as thawedembankments. One such embankment that has impoundeda reservoir since 1969 is the dam for theVilyui Hydroelectric Station located on the VilyuiRiver at the tom of Chernyshevskiy in Yakutia.The site of the dam and reservoir is underlain byPalaeozoic and Mesozoic sedimentary and volcanicrocks. Intrusive rocks are from the lower Triassicperiod. At the dam site, the rock to a depthof 30 m contains small fissures, some of whichwere open, containing only ice.The average air temperature at the site is-8.2'C and permafrost temperatures vary from -2 to-6'C depending upon the orientation of the groundslope with respect to solar radiation. Permafrostthickness varies from 200 to 300 m, but a talikextends entirely through the permafrost beneaththe river bed at the dam site. The cross sectionconsists of a rockfill shell with an inclined clayzone protected by two-layer filters upstream anddownstream. A concrete pad enclosing a groutinggallery forms the base of the impervious zone.Initial grouting into 4-m deep holes was performedto reinforce the blast-shattered rock and to reduceseepage beneath the concrete pad. Furthergrouting of the bedrock fissures is accomplishedas the ice melts from these fissures. The requirementfor further grouting is indicated bytemperature sensors and pioezometric measurements(Demidov, 1973).During the construction and operation of thisdam, ice built up in the pores of the downstreamrockfill (Melnikov and Olovin, 1983). Studies ofthe circulation of air within the rockfill indicatedthat the talik beneath the foruer river bedwas freezing. Moisture is entering the rockfillpores from convection, from precipitation, andfrom occasional tailwater backup. The ice formedfrom the tailwater is solid and remains at thebase of the fill, while that from precipitation isdistributed in the rockfill depending upon itstemperature distribution. As the voids in thebackfill become filled with ice, air currents aredamped and the freezing of the talik ceases (Melnikovand Olovin, 1983). The embankment dam hasbeen operating successfully since its constructionin 1969.Other high water-retaining embankments constructedon bedrock permafrost in the USSR arethose at Ust-Khantaysk and the Kolyma hydroelectricpower statim (Evdokimov et al., 1973; Gluskinet al., 1974; Tsytovich et al., 1978). Althoughthere is some Information describing theconstruction of these dams (Gluskin and Ziskovich,1973; Tsytovlch et al., 1974; Gluskin et al.,19741, the details of their performance are notavailable in western literature at this time. Itis assumed that they are performing aa designed.Two specific problem that have been givenspecial attention in the USSR literature are frostheaving and thermal cracking of embankmants.Since frost action can occur to depths of a fewmeters at the crest of an embankment, non-frostsueceptiblesoils, anti-heaving salting, and heat-ing have been suggested as measures to counteractthis problem (Kronik, 1973; Tsytovich et al.,1978). Transverse thermal cracking of embankmentshas been observed during and after the winter season.Cracks in one of the irrigation dams on theSuola River near Yakutsk were investigated byErechishchev and Sheshin (1973). They found thecracks occur within 1.5 m of the vertical walls ofthe wooden outlet structure. To protect againstthis type of cracking, a layer of gravel 2 m thickis being used at the crest of embankments on permafrostin the USSR. Grechishchev suggested embeddinghorizontal wooden rods near the crest parallelto the axis of the embankment, to act as reinforcementin the soil and prevent these cracks.A method of calculating the longitudinal thermaldeformation of embankments has been developed(Grechishchev and Sheshin, 1973) and the calculatedcrack widths are in good agreement withthose obeerved in the embankmnt under investigation.In Canada, the literature does not record theconstruction of an embankment designed as a frozenstructure on permafrost but it does reveal thatseveral small dikes (Johnston and MacPherson,1981) and a waste impoundloent (Thornton, 1974)were designed and constructed as the thawed typeof embankment on permafrost. In these designs,the amount of thaw consolidation that will occurin the foundation is estimated, and the embankmentheight is increased to accommodate the anticipatedsettlement. As an alternative to overbuilding thedikes, the design heights are maintained by periodicallyadding embanklaent material to the crestof the dikes as settlement progresses. In someinstances, vertical sand drains (Johnston, 1969;MacPherson et al, , 1970) are installed in the permafrostfoundation beneath the embankmnt to reducepore pressures and hence increase the shearingresistance of the soil while thawing occurs.The differential settlements associated with thistype of design can lead to transverse cracking ofthe embankments. To accommodate the cracking, theembankments were constructed of soils that areself-healing in nature (Johnston and MacPherson,1981). Essential to this type of design is a continuousobservation program throughout the life ofthe structure.Examples of thawed embankments founded onpermafrost in northern Manitoba, Canada, are thedikes at Kelsey (MacDonald, 19661, Kettle (Macphersonet al., 1970) and the Long Spruce (Keil etal., 1973) hydroelectric generating stations. Todate, these embankments appear to have been performingas envisioned by their designers.In the United States, one 24-m-high water-retainingembankment, five small embankment damsless than 6 m high, and a few levees have beenconstructed on permafrost in Alaska and one inThule, Greenland. The small water-supply dams atremote villages are of the frozen type of designand are without artificial cooling. Although somehave been in operation far more than 30 years(Davis, 1966; Fulwider, 1973), no serious problemshave been reported. The largest embankment damfounded on permfrost in Alaska is located nearLivengood on Hess Creek (Rice and Simoni, 1966;Kitze and Simoni, 1972). This combination hydraulicfill and rolled earth fill structure was

37completed in 1946 to a maximum height of 24 m.The foundation consists of silt and ice to a depthof approximately 6 m overlying a 6.53 thick depositof a variable mixture of frozen clay, silt,sand, gravel, and fragments of chert rock. Beneaththis deposit and overlying the fracturedchert bedrock is a 6.S-m layer of frozen coarsesands and gravels containing considerable ice.After stripping the site, the hydraulic fill wasplaced directly on the frozen silt. Horizontalcooling pipes were installed at the surface of thefoundation to provide artificial refrigeration tokeep the foundation frozen during construction.Steel sheet piling embedded in permafrost and projected2 to 3 m up into the hydraulic fill wasused to improve the seepage cutoff. Since thisdam only retained water during the short summermining period each year, the reservoir was loweredevery autumn to take advantage of winter coolingto preserve the permafrost foundation and refreezethe embankment. This dam performed satisfactorilyfrom 1946 until 1958, when the mining operationswere stopped for economic reasons. The major operatingdeficiency in the system was a water outlettunnel located remotely from the dam. It completelycollapsed some time after the mining operationceased. Then in 1962, the overflow from thespring runoff washed out the timber spillway thatwas located on the right abutment of the dam. Theembankment itself remains intact today.Embankrent Dams on Permafrost: Recorded Failuresand ProblemsEmbankment dams on permafrost have been builtand successfully operated in Canada, the USSR, andAlaska. A number of failures have been reportedin the USSR and one in Alaska. Table 1 lists 15embankment dams that encountered difficulties;sow of the problems were corrected, but severalended in disaster. An examination of the tablereveals that most of the difficulties arose becauseinsufficient attention was given to establishingand maintaining a reliable frozen thermalregime and to controlling seepage. It should benoted that often the thawing and seepage in a frozenembankment or foundation are Initiated adjacentto the spillway or outlet works. This, ofcourse, indicates that inadequate cooling or cutoffswere established at these points. Otherproblems described in the table can be tracedto the construction procedures and the control ofearth placement. In some cases, adequate thermalprotection was not provided for the foundation andadjacent areas during construction. In other cases,insufficient compaction was applied to thesoil placed in the frozen state.Table 1 includes only a portion of the problemsthat have been referenced in the literature.Although several papers on embanklnent darns on permafrosthave been collected and translated, it isreasonable to assume that there are many eitherunreported or not available in our limited bibliography.However, the dam that are listed indicate,the problem that mst be addressed if safeand economical embankment dams are to be built onpermafrost.RESEARCH REQUIREDThe design, construction, and maintenance ofsafe, water retaining embankments in the Arcticand sub-Arctic is strongly dependent upon suchconsiderations as structural stability, seepagecontrol, the handling of materials, erosional control,and the envfronmental effect of the iqoundment.The following is a list of areas that needfurther research:a. The development of analytical methodsfor determtning and predicting the thermalregime within and beneath water-retainingembankments on permafrost whenground water seepage occurs and wherethree-dimensional heat flow is important.b. The development of effective methods forcontrolling the thermal regime and seepage,especially at locations contiguousto spillways and outlet works for embankmentson permafrost.C. The development of drainage systems thatwill not become plugged wlth ice.de The analysis of existing techniques andthe developent of new ones for constructingfrozen and unfrozen embankmentdam on permafrost during both the 8ummerand winter construction seasonswhile maintaining a frozen foundation.e. The development of more accurate analyticalprocedures for determining thestability of embankment and natural andcut slopes in permfrost during thawing.f. The development of accurate methods thatuse electromagnetlc, geophysical, andother types of tools €or determining theextent and depth of permafrost, massiveice inclusions, and types of soils atproposed embankment sites.g. The development of instrumentation formonitoring the construction and performanceof embankments on permafroat, withspecial attention to early detection ofseepage that occurs in a "frozen" emh.bankment or its foundation.The determination of the effects of impoundmentson water chemistry and productivityin reservoirs and streams overpermafrost.i. The development of biological proceduresfor restoring reservoir landscapes inarctic and subarctic areas.j. The determination of the tolerance ofcold-dominated vegetation to periodicinundation.k. The validation of existing methods forpredicting the hydrological characterirticsof catchment basins on permafrost.1. The development of effective methods forcontrolling water and ice erosion of embankments,cuts, and natural slopes ofreservoir walls in permafrost areas.

38River nalreLocationTABLE 1 Embankment dams on permafrost: Problems with existing damsEmbankmentHeight Lengthtype ( m) ( m) Problem/description ReferenceThawing and Seepage at Spillway and Outlet WorksUnknown Northern USSR Compact earth21.4 230 Municipal water dam supplywas completed in 1967. In1970, a breach occurredthrough embankment at supplyintake pipes due to ther-~81 erosion and seepage.Anisimov 6 Sorokin,1975Hess Creek Livengood, AK Hydro L compactearth fillMyla River Zarechnyy Region,USSRCompact frozen sand24 488 Completed in 1946 For watersupply in mining operations.In 1962 breached betweenspillway due tn therm1 erosionand seepage.- Constructed of uncompactedfrozen sand during winter.Seepage through earth damand joints in wooden sptllwaycaused thawing and failureof dam in 1954.Rice 6 Simoni, 1966Lyskanov, 1964Vilyui River USSR(Dam 11)Vilyui River USSR(Oam 111)Embankment wlcribcutoff, w/sandand siltEmbankment with 3core12 300 Constructed 1957-1960 on per- Biyanov, 1966mafrost. &iring initial operatingperiod, large seepagevolume occurred and spillway was completely destroyedin First Elood. After reconstructionin 1969, leakage wayobserved from the reservoirthrough caverns in foundationof the dam and at contact withthe spillway. Causes of problems:(I) spillway too smallfor flood, (2) ice-retainingstructures not located farenough upstream from dm, (3)poor spillway construction, (4)fissures in foundations notsealed, (5) poorly compactedrunoff.- Clay-ice core constructed Biyanov, in 1965winter with frozen clay andwater. Seepage along spillway;contact between it andthe embanknest resulted indegradation of frozen core,which soon became nonfunctional.Thermal Regime of Embankment and Foundation not MaintainedDolgaia River Norilst, USSR Refrigerated earth 10 130Constructed in 1942 witha "clay-concrete" (probablycement-stabillzed clay) corewith two rows of freezingpipes parallel to dam axie."he core was to reduceseepage during the freezingperiod. Calcium chloridebrine, circulated throughthe freezing pipes, was notcooled sufficiently by atmosphere.Furthermore, thehrine leaked into the dam,causing melting of embankment.Snow deposits lmpededfreezing from the domscreamface. Disaster wasaverted by converting the'cooling brine to atr and runningthe circulatia systemonly when air temperatureswere colder than the ground.Only after an ice sheet wascreated on the downstream faceby water application8 in thewlnter was thermal regirm stabillzedthroughout the year.Tsvetkova, 1960,Borisov & Shamhura,1959SredniyEl'gen RiverKolyma River Earth 7.4 300 Built in 1944. Large defor-Basin, USSRmations and cracks occurredalong dam due to seepage andthawing. Seepage developedTsvetkova. 1960

39TABLE I (cont'd) Embanmknenc dams on permafrost: Problems with existing damsEmbankmentHeight LengthRiver name Location type ( m) ( m) Problemldescription Referencewhere timber piling was usedas a cutoff. To prevent failurean upstream blanket wasCcmSCKUCted.NyaundzhaRiverKolyma Basin,USSREarth fill 8wlcoreIn 1952, initial attemptsmbde to construct dam inthe winter to obtain a frozenembankloent, but thawingin the summr required artificialcooling. This wasaccomplished by installing"freeze" pipe in the embankmentand circulating cold airdown the pipes. 'Rle abutmentswere not protected byfreeze pipes, thawing occurredat these locatlons, and theseepage ensued. (This article,in 1957, implied impending disaster.)Tsvetkova, 1960Amoear RiVeKNear Mogochaon the AmrRailroad.Crib-core 4RO&-eaKth fillFailed due to seepage andthawing through body of theembankuent. (Apparentlyhilt in 1910-1916.)Tsvetkova, 1960KvadratnyyNorilsk, USSRCompact earth fill 6Dam used for cooling watersupply for electric powerstation. Destroyed withinI yr after constructionby thawing of foundationsand abutment Soils.Borisov &Shamahura, 1959Stake 89(Picket Creek)Norilsk, USSRConpact earth fill 5.5Destroyed within 2 yr afterconstruction when seepagethrough the unfrozen soilthawed the frozen soil.Tevetkova, 1960PravayaMagdagachaRiverNorthern USSRInadequate Construction ProceduresCompact earth with 1.3 - Failed after 2 yr of opera- Tsvetkova. 1960;concrete diaphragm tion. Large deformationof Saverenskii, 1950dam resulted in cracks inthe diaphragm ail along theembankrent dam and at thejunction of the weir. Finalfailure occurred during heavythunder storm when leakageappeared at the crest. Failureoccurred over a 653length.Mykyrt River City of Petrovsk- EarthUbaykalskiy, USSR9.5 - Built In 1792. In attempting Tsvetkova. 1960to repair the wooden spillwayof the 137-yr-old dam, propermeasures were not taken to preservethe frozen embankuent.The dam had to be completelyrebuilt in 1945.Bol'shay Skovorodino, USSR Earth silt and 9.6 530 Built in 1932. Ihe clay-ice Tsvetkova, 1960Never Rivergravel with claycore became semi-liquid andcore the stabiltty of the dm wasthreatened. In 1934 ballastwas applied to the slopes,wooden piling was driven,soil behind the piling wasreplaced by more imperviousrmterial. and a wood gallerywas consrrucced to catch theseepage. Deep thawing offoundation soil and bedrockin 1936 did not cause aeriousproblems.Vilyui River USSR(Dam V)Random earth fill 16.8with timber332 Constructed on ice-saturated BiyanOV, 1965clayey silt and disintegratedrock overlying fissured claylimestone.In the springs of1965 and 1966 boils appeareddownstream of the dam. Seepagewas caused by thawing ofice in rock fissures during

40REFERENCESAnisimov, V.A. and Sorokin, V.A., 1979, Repairwork on a frozen dam (in Russian): GidrotekhnicheskoeStroitel'stvo, no. 5. (Trans. )Hydrotechnical Construction (19751, p. 24-25.Belikov, M.P., Panasenko, G.A., and Antsiferov,A.S., 1968, Earth dam in permafrost regionconstructed with plastic waterproof barrier(in Russian): Gidrotekhnicheskoe Stroite1'-stvo (Hydrotechnical Construction), no. 10,p. 878-880.Biyanov, G.F., 1966, Discharge and blocking up theriver during construction of the Vilyui HydroelectricPower Station (in Russian): GidrotekhnicheskoeStroitel'stvo (HydrotechnicalConstruction), no. 2, p. 1-5. (Trans.) NationalResearch Council of Canada, TechnicalTranslation 1353, 1969.Biyanov, G.F., 1970, Experience in constructionand operation of luw-head dams on permafrostsoils (in bssian): GidrotekhnicheskoeStroitel'stvo (Hydrotechnical Construction),no. 9.Biyanov, G.F., 1973, Experience in building damson permafrost in Yakutia (in Russian),Proceedings of the Second International Conferenceon Permafrost, Yakutsk, V. 7, p. 125-132. (Trans.) Hanover, N.H., U.S. Army ColdRegions Research and Engineering Laboratory,Draft Translation 438.Biyanov, G.F. and Makarov, V.I., 1978, Characteristicsof construction of frozen dams inwestern Yakutiya, Proceedings of the ThirdInternational Conference on Permafrost, Edmonton,V. 1: Ottawa, National ResearchCouncil of Canada, p. 779-784.Bogoslovskii, P.A., 1958, Investigations on thetemperature regime of earth dams under permafrostconditions (in Russian): Nauchnye DokladyVysshei Shkoly, Stroitel'stvo, no. 1,p. 228-238. (Trans.) Hanover, N.H., U.S.Army Cold Regions Research and EngineeringLaboratory, Draft Translation 22, 1966.Bogoslovskii, P.A., 1970, Analytical calculationof a three-dimensional, stationary, steadystatetemperature condition of a dam (in Russian):Sbornik trudov PO gidrotekhnike 1gidrostroitel'etva pri stroitel'stve plotin veuravykh klimaticheskikh usloviyakh.(Trans.) Hanover, N.H., U.S. Army Cold RegionsResearch and Engineering Laboratory,Draft Translation 601, 1977.Bogoslovskii, P.A., Veselov, V.A., Ukhov, S.B.,Stotsenko, A.V., and Tsvid, A.A., 1966, Damsin permafrost regions, Proceedings of theFirst International Conference on Permafrost,Purdue University, 1963: Washington, D.C.,National Academy of Sciences, p. 450-455.BOrisov, E.A. and Shanmhura, G.Ia., 1959, Experiencein the planning, construction and use ofearth darns at Noril'sk (in Russian): MaterialyPO inzhenernomu merzlotovedeniiu, 7th LnterdepartmentalPermafrost Conference, USSRAcademy of Sciences. (Trans.) Hanover, N.H.,U.S. Army Cold Regions Research and EngineeringLaboratory, Draft Translation 26, 1970,p. 110-119.Brown, W.C. and Johnston, G.H., 1970, Dikes onPe= frost: predicting thaw and settlement:Canadian Geotechnical Journal, V. 7, no. 4,p. 365-371.Davis, R.M., 1966, Design, construction, and performancedata of utility systems, Thule AirBase: Hanover, N.H., U.S. Army Cold RegionsResearch and Engineering Laboratory, SpecialReport 95.Demidov, A.N., 1973, Dam in the Vilyuy hydraulicpower system (in Russian): Trudy Gidroproekta,no. 34, p. 64-77. (Trans.) Hanover,N.H., U.S. Army Cold Regions Research and EngineeringLaboratory, Draft Translation 526,1976.Evdokimov, P.D., Bushkanets, S.S., Zadvarny, G.M.,and Vasiliev, A.F., 1973, Studies of foundationsand earth rockfill dams under severeclimatic conditions: Seminar No. 2, Experienceof Hydro Project Construction under SevereCliatic Conditions, Leningrad, JointSoviet-Canadian Working Group for Co-operationin the Electrical Power Industry, p, 67-86.Fulwider, C.W., 1973, Thermal regime in an arcticearthfill dam, Permafrost - The NorthAmerican Contr;bution to the Second InternationalConference, Yakutsk: Washington,D.C., National Academy of Sciences, p. 622-628.Gapeev, S.I., 1967, Consolidation of the frozensoils of foundations by cooling (in Russian):Gidrotekhnicheskoe Stroitel'stvo, no. 12.(Trans.) Hydrotechnical Construction, no. 12,p. 1082-1084.Gluskin, 1a.E. and Ziskovich, V.Ye., 1973, Damconstruction in the Northern USSR (in hssian),Proceedings of the Second InternationalConference on Permafrost, Yakutsk, V.7. (Trans.) Hanover, N.H., U.S. Army ColdRegions Research and Engineering Laboratory,Draft Translation 438.Gluskin, Ia.E., Losev, E.D., Petrov, V.C., andFrumkin, N.V., 1974, Kolyma hydroelectricstation (in Russian): GidrotekhnicheskoeStroitel'stvo, no. 8, p. 722-727.Grechishchev, S.E. and Sheshin, Iu.B., 1973, Theoreticaland experimental studies of thermalstresses and defomtions of earth dame inwinter (in Russian): All-Union ScientificResearch Institute of Hydrogeology and EngineeringGeology, USSR Ministry of Geology,Trudy, unpublished MS, no. 55 (S. E. Grechishchev,ed.), Moscow. (Trans. ) Hanover, N.H.,U.S. Army Cold Regions Research and EngineeringLaboratory, Draft Translation 449.Gupta, R.C., Marshall, R.G., and Badke, D., 1973,Instrumentation for dikes on permafrost, KettleGenerating Station: Canadian GeotechnicalJournal, V. 10, no. 3, p. 410-427.Johnson, T.C. and Sayles, F.H., 1980, Embankmentdams on permafrost in the USSR: Hanover,N.H., U.S. Army Cold Regions Research and EngineeringLaboratory, Special Report 80-41.Johnston, G.H., 1965, Permafrost studies at theKelsey Hydroelectric Generating Station, researchand instrumentation: Division ofBuilding Research, National Research Councilof Canada, Technical Paper No. 178.Johnston, G.H., 1969, Dykes on permafrost, Kelsey

41Generating Station, Manitoba: Canadian GeotechnicalJournal, V. 6, no. 2, p. 139-157.Johnston, G.H. , and MacPherson, J.G., 1981, Damsand reservoirs, ch. 9, &Permafrost EngineeringDesign and Construction (G.H. Johnston,ed.): New York, John Wiley & Sons, p.393-413.Kamenskii, R.M., 1973, Thermal regime of bearingground and of the body of the Vilyui hydroelectricpower plant (in Russian), & Pro-ceedings of the Second International Conferenceon Permfrost, Yakutsk, V. 7, p. 228-235. (Trans.) Hanover, N.H. , U.S. Army ColdRegions Research and Engineering Laboratory,Draft Translation 438, p. 300-308.Keil, LO., Nielsen, N.M. , and Gupta, R.C., 1973,Thaw-consolidation of permafrost dyke foundationsat Long Spruce Generating Station, Manitoba,& Proceedings of the 26th CanadianGeotechnical Conference: Toronto, p. 134-141,preprint.Khakimov, Kh.R., 1963, Artificial freezing ofsoils - theory and practice (in Russian).(Trans.) A. Barouch and H. Heimann, NTIS:Springfield, Va. U.S. Department of Commerce,1966.Kitze, F.F., and Simoni, O.W., 1972, An earth filldam on permafrost: Hess Creek Dam, Livengood,Alaska: Hanover, N.H., U.S. Army ColdRegions Research and Engineering Laboratory,Technical Report 196.Kronik, Ia.A., 1973, Cryogenic phenomena in hydraulicstructures built of earth (in Rus-sian), Proceedings of the Second InternationalConference on Pemfrost, Yakutsk, V.7, p. 316-320. (Trans.) Hanover, N.H., U.S.Army Cold Regions Research and EngineeringLaboratory, Draft Translation 438, p. 240-243.Lyskanov, G.A. , 1964, Experimental construction ofa frozen-type dam in Iakutiia (in Russian):Yakutsoe Knizhnoe Izd-vo. (Trans. ) Hanover,N.H., U.S. Army Cold Regions Research and EngineeringLaboratory, Translation 479, 1975.MacDonald, D.H., 1966, Design of Kelsey dikes, inProceedings of the First International Conferenceon Permafrost, Purdue University,1963: Washington, D.C. , National Academy ofSciences, p. 492-496.MacPherson, J.G., Watson, G.H., and Kuropatnick,A., 1970, Dikes on permafrost foundations innorthern Manitoba: Canadian GeotechnicalJournal, V. 7, no. 4, p. 356-371.Melnikov, P.I. and Olovin, B.A., 1983, Permfrostzone dynamics In the area of the Vilyuy Riverhydroelectric scheme, Proceedings of theFourth International Conference on Permafrost,Fairbanks: Washington, D.C. , NationalAcademy of Sciences, p. 838-842.Mukhetdinov, N.A., 1969, Thermal regime of thedownstream shoulder of rockfill dams (in Russian):Energiya, Leningrad, v. 90, p. 275-294. (Trans. ) Hanover, N.H. , U.S. Army ColdRegions Research and Engineering Laboratory,Draft Translation 586, 1977.Rice, E.F. and Simoni, O.W., 1966, The Hess CreekDam, Proceedings of the First Internation-al Conference on Permafrost, Purdue University,1963: Washington, D.C., National &ademyof Sciences, p. 436-439.Sanger, F.J. and Sayles, F.H., 1978, Thermal andrheological computations for artificiallyfrozen ground construction: 1st InternationalSymposium on Ground Freezing (H.L. Jessberger,ed.), Bochum, Germany, Ruhr University,V. 2, p. 95-117.Savarenskii, F.P., 1950, Dam in permafrost regions(in Russian) : Izbrannye socheneniia,p. 370-371. (Trans.) Arctic Construction andFrost Effects Laboratory (USAED), ACFELTranslation No. 29, 1960.Semenov, N.G., 1967, Building dams in permafrostregions (in Russian): GidrotekhnicheskoeStroitel'stvo, no. 9, p. 14-15. (Trans.)Hanover, N.H., U.S. Army Cold RegionsResearch and Engineering Laboratory, DraftTranslation 452, 1974.Sereda, V.A., 1959, Experience in planning hydraulicstructures with prolonged soil freezing(in Russian): Seventh Interdepartmental PermafrostConference, USSR, Academy of Sciences,p. 120-128. (Trans.) Hanover, N.H. ,U.S. Army Cold Regions Research and EngineeringLaboratory, Draft Translation 140, 1966.Smirnov, E.A. and Vasiliev, S.F., 1973, Design andconstruction of earth and rock fill dams undersevere climatic conditions, USSR experience:Seminar No. 2, Experience of Hydro ProjectConstruction under Severe Climatic Conditions,Leningrad, Joint Soviet-CanadianWorking Group for Co-operation in the ElectricalPowerThornton, D.E., 1974, Waste impounding embankmentsin permafrost regions: the oxidation pondembankment, Inuvik, N.W.T: Task Force onNorthern Oil Development, Environmental SocialCommittee, no. 74-10, p. 159-193.Trupak, N.G. , 1970, Construction of earth dams onpermafrost EOih (in Russian): GidrotekhnicheskoeStroitel'stvo, v. 40, no. 9, p. 8-11. (Trans.) Hydrotechnical Construction,no. 9, p. 798-803.Tsvetkova, S.G., 1960, Experience in dam constructionin permafrost regions (in Russian): Materialyk osnovam ucheniia o merzlykh zonakhzemnoi kory, V. 6, p. 87-112. (Trans.) Hanover,N.H. , U.S. Army Cold Regions Researchand Engineering Laboratory, Draft Translation161, 1966.Tsvid, A.A., 1961, Freezing oE an earth dam fromthe dry slope side (in Russian): SbornikNauchnykh Rabot, V. 1, p. 93-104. (Trans.)Hanover, N.H., U.S. Army Cold Regions Researchand Engineering Laboratory, DraftTranslation 430.Tsytovich, N.A., 1973, The mechanics of frozenground (in Russian): Moscow, Vysshaya ShkolaPress. (Trans. ) G.K. Swinzow and G.P. Tschebotarioff, eds.) , New York, ScriptaIMcGraw-Hill, 1975.Tsytovich, N.A., Ukhova, N.V. , and Ukhov, S.B. ,1972, Prediction of the temperature stabilityof dame built of local materials on permafrost(in Russian): Leningrad, Stroiizdat,

42p. 143. (Trans.) Hanover, N.H., U.S. ArmyCold Regions Research and Engineering Laboratory,Draft Translation 435.Toytovich, N.A., Kronik, Ya.A., and Biyanov, GF.,1978, Design, construction, and performanceof earth dam on permafrost in the Far North,- in Proceedings of the Third InternationalConference on Permafrost, Edmonton: Ottawa,National Research Council of Canada, p. 137-149.

DESIGN AND CONSTRUCTION OF DEEP FOUNDATIONS IN PERMAFROST:NORTH AMERICAN PRACTICEB. LadanyiEcole PolytechniqueMontreal, CanadaIn the last 20 years, the design and constructionof deep foundations in permafrost inNorth America have seen quite remarkable developments,due to a combination of performance observations,field testing, and theoretical work. Inparticular, during this period, a great number offull-scale pile tests were performed in Alaska andnorthern Canada. These tests helped greatly toclarify the behavior of different types of deepfoundations in permafrost under load and temperaturechange. Most of the work was done in theareas of pile installation methods, the behaviorof piles and anchors under axial compression andtension loads, and the determination of adfreezestrength of various types of piles. AB a result,we now have a relatively good idea of how a pile,installed by a given method, will behave under anaxi a1 load.Nevertheless, there are still several problemsin relation to deep foundations whose solutionwill require further experimental and theoreticalwork in the coming years. It is thereforeuseful to review the research areas that have beencovered in the North hrican literature on deepfoundations in permafrost over the last 20 years,to see where it may be necessary and justified toconcentrate future research efforts.For a faster survey of information, the reviewwas subdivided into five subject groups, eachcovering one large research area. These are:A. Pile installation methodsB. Pile behavior under loadC. Improvement of pile bearing capacityD. Design methods for piles in permafrostE. State-of-the-art reviews, literature surveys,and general design recommendationsEach subject group contains several subgroups,each dealing with a particular subject oran investigated effect on pile behavior.The subgroups contain a list of all reviewedbibliographical references dealing with the subjectmatter. These references, listed at the endof the report, are subdivided into five groups:1. Piles and deep footings (Ref. Pl to P48).2. Deep anchors (Ref. AN1 to AN8).3. Adfreeze bond (Ref. AD1 to AD1 1).4. Frost heave effects on piles (Ref. FHl toFH6).5. Foundation materials (MAT1 to MAT3).Under each subheading, there are only somebrief statements on the state of knowledge on thesubject, while the areas of needed research arelisted at the end of the paper.While a great effort has been made to includeall published references, this does not wan thatthere are no inevitable omissions, such as unpublishedinternal reports and reports of a proprie-tary nature. It is hoped that this valuable 1 information,especially on the performance of thevertical support members of the Alyeska pipe line,will become available in the near future.LITERATURE REVIEWA. Pile Installation MethodsAl.Freezeback of slurry around piles, theoryand observations (P3, P32, P33)The thermal problem has been solved theoretically,and the predictions appear to agreewith field observations. The mechanicalproblem of freezeback pressures needsfurther work, but it is known thatsome(a) 'he pressures dissipate quickly in warmpermafrost;(b) They have a positive effect on pile capacityin dense frictional frozen soil,but it is safe to neglect them in design ;(c) The pressures are important to considerwhen evaluating results of pile tests.A2. Experience with driving piles in permafrost- soils (P20, P22, P25, P26, P27, P38, P43,P44, P46)(a) Steel piles, including H-shape, reinforcedweb, and sheet, can be driven inmost frozen soils (except frozen gravelsand cobbles) with Impact, vibratory, orsonic hammers;(b) When extremely hard driving is encountered,an impact hemmer and cast-steelpile driving tips are necessary;(c) Pile driving using thermally modifiedpredrilled pilot holes is finding increasinguse in practice;(dl In plastic-frozen soils, driving inslightly smaller holes is possible andgives high pile capacities. The methodbecomes difficult in cold permafrostsoils.A3. Comparison of driven and slurried piles (P4,P14)Steel H-piles when driven have 3 to 4 timeshigher capacity and much smaller settlementthan when installed in slurried holes.A4. Experience with different types of backfillslurries (P2, P46)43

44A5.B.B1.B2.B3.In order of increasing adfreeze strength ofslurries is: clay, silt, sand, sand-vibrated,cement grout.Experience with cast-in-place piles infrost (P32, AN1 to AN5, MAT31perma-Cement-fondu-sand-water (1:l:llZ) groutused in Thompson and Gillam testsresulted in a corrugated, ice-freeinterface with the soil.A gypsum-based cerpent grwt provides earlystrength at low temperatures, butform a layer of saline unfrozen soil atthe pile interface, reducing adfreezebond.Pile Behavior Under LoadCompression tests on piles (P2, P4, P5, P10,P28, P40, P45, P46)The load-settlement curve and pile capacitydepend on the rate of loading.There is disagreement on the yield orfailure criterion for pile tests.Driven piles carry more and settle lessthan those installed in slurried boreholes.There is no standard method of testing.No design method gives the optimum L/dratio for a pile.For long piles, only a small portion ofthe load is carried by the end bearingat service loads. The portion increaseswith time.Attenuating creep is usually observed atlaw stresses (settlements), and steadystatecreep at high stresses (post-failuresettlements).For piles in ice, steady-state creep canbe attained at all loads.In slurried piles, end contact is notassured without driving the pile.Tension tests on piles (AM, AN1 to AN51(a) Failure was observed in tension tests;there was no distinct failure in compressiontests with end-bearing.(b) Break of the bond occur6 at a given displacement,probably depending on theroughness of the pile surface.(c) When the bond is intact, there is a power-lawrelationship between creep rateand stress.Behavior of anchors and anchor systemP33, AN1 to AN7)(P13,The response to the load depends on theanchor type and the installation laethod.Deep plate anchors need more displacementsfor mobilizing the soil resistancethan rod anchors, but may have higherultimate safety factors because they relyon the weight of the soil conelifted.Adfreeze bond (effects of soil type, pile material,temperature, rate of loading, sheardisplacement) (P2, P33, P34, P40, P41, P44)(a) Tables and graphs of short- and longtermvalues are available for differenttypes of soils and pile materials.(b) Sometimes a layer of ice or unfrozen(saline) soil forms on the pile interfaceduring refreezing.(c) The adfreeze bond increases with icecontent but decrease6 again after thesoil is super saturated with ice.(d) Bond creep is governed by a power law ofstress relationship.(e) The bond breaks at a given displacement,in a brittle manner, falling to a muchlower residual value.Stress distribution alonR the pile and loadtransfer to the pile pointP41, AD11)(P2, P32, P40,(a) Stress distribution depends on installationmethod, pile type, load level, andtime.(b) For a given load, the bond stresses, initiallydecreasing with depth, becomemore uniform with time, and more load istransferred to the end.(c) At a settlement of 5-1OX of the pile diameter,2540% of the total load may becarried by the base. At service loads,the point-bearing load may be negligible.(d) For driven piles, the load transfer tothe pile point depends on the settlementrate under service loads.(e) There is a limit of displacement forbond failure, depending on the soil andpile roughness.(f) Dynamic loads lead to bond reduction andan increase in load transfer to thepoint.Theories of stress redistribution for compressiblepiles due to soil creep (P19, P32)Under a constant load, lateral stress is redistributedalong a compressible pile in thefirst 24 hours, with a tendency to make thedistribution mre uniform and to transfermore load to the base. Pile creep curves maynot be representative within that period.Effect of seasonal soil temperature variationon pile settlement (P17)Seasonal variation of the end-bearing loadoccurs due to freezing and thawing of the activelayer and the temperature variation ofpermafrost within the embedded pile strength.Effect of slow load cyclingrate (P30)on penetrationThe penetration rate becomes practically independentof the loading history after the

45B9.penetration resistance is fully mobilized(i.e., total settlement exceeds about 10% ofpile diameter).Scale effects in pile loadingP32, P42)tests (P18,Results obtained with piles of different diametersare comparable at the same strainrate, but not at the same penetration rate.Both end-bearing and adfreeze bond arehigher if piles are driven into partiallyslurry-filled oversized boreholes.Driving in slightly smaller holes, withoutslurry, also gives nuch higher bondstrength, but it is limited to relativelywarm plastic frozen soils. Thermallymodified pre-drilled pilot holes facilitatedriving without decreasing adfreezestrength.B10. Frost-heave effects on piles (FH1 to FH6)Frost uplift stresses measured on verticalembedded columns vary mostly between50 and 100 kPa, with short-term peaks upto 200 kPa. They are highest for steelcolumns, followed by concrete and wood.Frost uplift stresses are proportionalto the heave rate.Peak values of uplift stresses occurduring the early freezing period, whenheaving rates are high, but maximum upliftforces often occur near the tir ofmaximum frost penetration, late in thewinter season.For steel columns, uplift stresses tendto decrease with increasing pile diameter.Frost-heave forces increase with pileinclination in the active layer.B11. Lateral loadina tests on piles (P8, P9, P16)By putting the results of tests in theform of a power law of time and load, atime-dependent modulus of lateral soilreaction and a p-y curve can be deducedfrom the tests.The pressuremeter test data have beenused with good success to predict theoreticallythe behavior of laterallyloaded piles in permafrost.Most published test results refer tostage-loaded tests with 24 h per stage.Behavior under long-term sustained loadsand cyclic loads needs further study.c3.D.Dl.Deterioration of pile materials in permafrost(M4T1, MATZ)(a) Steel piles: no corrosion was detectedafter 6-1 1 years of exposure to activelayer conditions at three sites in Alaska.(b) Timber piles: fungus attack was detected.Improved treatment proceduresshould be applied.Desixn Methodsfor Piles in PermafrostDesign methods based on laboratory-determinedparameters (P13, P15, P16, P19, P23, P30,P31, P32, P33, P34, P36, P37, P41, P44)Although based on small strain assumptions,the theories for creep settlementof piles under axial and lateral loadsseem to give reasonable predictions forshort- and medium-term loads. More information'andcomparison with field datais needed for long-term behavior ofpiles under static and dynamic loads.End-bearing support is negligible forpiles in all types of homogeneous frozensoils at service loads.It is suggested that pile design in ice--rich soils is governed mainly by settlemnt,while in ice-poor soils the designshould satisfy both settlement andstrength criteria.It is also suggested to neglect in designsoils with temperatures above -1'C.C.c1.c2.Improveuent of Pile Bearing CapacityThermopiles (Pi', P12, P17, P21, P46)To select the best system, a careful study ofground and temperature conditions should bemade. With an appropriate system, excellentresults can be obtained.New pile designs or installation methods forincreased adfreeze bond and/or end-bearing(P12, P20, P21, P22, P27, P39, P40, P44, P45,Use of corrugated and helix-type pilesconsiderably increases the bond strength(50-150%). The same was found forgrooved and tapered concrete piles inslurried holes.Use of lugs around a pile considerablyincreases its bearing capacity.D2E.Desim methods based on field test results(P9, P16, P18, P42, P46)If properly generalized, the results offull-scale tests on axially and laterallyloaded piles can be used directly forthe design of other piles under similarconditions. Nevertheless, extrapolatingsuch test results to the very long termremains uncertain until further verification.Well-controlled static cone penetrationtests can be interpreted as small-diameterpile tests. Their results can beused for the design of driven piles, eitherdirectly through a strain ratescaling law, or indirectly after determiningthe frozen soil creep parameters.State-of-the-art Reviews, Literature Surveys,and General Design Recomroendations (Pl, P3,

46P6, P7, P11, P23, P24, P25, P31, P32, P33,P34, P35, P36, P37, P38, P40, P41, P43, P44,P48)Several excellent state-of-the-art reviews ofexperience with piles in permafrost have beenpublished in the last 20 years, and a completecoverage of current or recommended designprocedures was described in special volumes(P31, P33, P37). Certain papers andvolumes also contain recommended design parametersfor piles in typical permafrostsoils (P6, P23, P31, P32, P33, P34, P37, P41,P44).RESEARCH REQUIREDA. On Pile Installation Methods(1) Driven pilesFurther development and testing is needed ofvibratory and sonic hammers, together withthermally treated, pre-drilled pilot holes.(2) Drill-driven piles (in smaller boreholes)In plastic-frozen 80118, cylindrical pilesdriven in slightly smaller pre-drilled holeshave shown increased adfreeze strengths.Diasipation of the mobilized lateral normalstress due to frozen soil relaxation shouldbe studied. Driving tapered piles in taperedpre-drilled holes seem promising and shouldbe tried in the field.(3) Slurry-driven pilesDriving of piles in larger holes, partiallyfilled with sand-slurry, was found to givehigh pile capacities. The method should befurther investigated to find the optimum designand installation method for such pilesand to evaluate their long-term performance.(4) Slurried piles (in larger boreholes)Freezeback pressure and its dissipationshould be studied further. If a portion ofthis pressure can be preserved permanently,the bearing capacity of a pile in granularslurry could be considerably increased. Thebehavior of corrugated and tapered piles inslurry-filled boreholes should be studied.(5) Cast-inplace pilesPiles should be made in such a manner thatthe concrete is compacted in the hole to producea good end-bearing mobilization and acorrugated lateral surface for a betterbond. A method similar to that used in makingFranki piles seems promising.B. On Pile Behavior Under Load(1) There is a need to establish a standardtesting method, especially with regard tothe length of the loading stages, theloading sequence, and the criterion ofyielding or failure. Possibilities forlong-term extrapolation of test resultsshould be explored.(2) Most piles in permafrost have a very highL/d ratio. For that reason, even drivenpiles carry very little load in end-bearing.The portion of the load carried bythe end-bearing is a function of the pilecompressibility, the pile installationmethod, the aspect ratio L/d, and thetotal settlement of the pile. The designmethod should be able to give an optimumLid ratio for which both rhe adfreezebond and the end-bearing are properlyutilized at an acceptable settlement orsettlement rate of the pile.(3) Ebre information is needed about thelong-term effects on the behavior of apile under service loads of the seasonaltemperature variation in the portion ofpermfrost in which the pile is embedded.(4) Very little information is available onthe long-term behavior of laterally loadedpiles. Additional information isneeded on the redistribution of lateralreaction with time and on the best method€or its prediction. The behavior of suchpiles under cyclic loads is also needed.(5) There is little information on pilegroups in permafrost loaded vertically.Since the group action may be affected bythe rate of penetration in frozen soilsmuch more than in unfrozen soils, thiseffect should be investigated.C. On Improvement of Pile Bearing Capacity(1) StraiFht-shafted pilesBesides the soil type, ice content, and temperature,the bond also depends on the pilematerial and the roughness of the shaft. Adfreezebond on a smoth shaft is regularlyuuch smaller than the shear strength of frozenaoil, and becows still smaller if theshaft is covered with a thin layer of ice.In addition, test results shad that after thebond fails a large portion of the bondstrength is permanently lost, because the adhesionbond falls in a brittle manner. It isnot clear whether the broken bond heals withtime. To improve pile performance, which dependsminly on the bond, the use of specialtypes of piles, as described below, is suggested.(2) Corrugated pilesWith a surface so rough that Eailure will beforced to occur within the frozen soil massand not along the pile-soil interface.(3) Tapered pilesBy their displacements, tapered piles assurea good contact with the soil and a constant

47normal pressure on the shaft, furnishinga constant frictional portion of the totalbond resistance if the pile is roughand surrounded by a frictional frozen P4.soil. Because they are supported by chesurrounding soil mass, such piles are expectedto show an essentially plastic responsewithout of strength. lossP5.(4) In general, the research should be orientedtoward finding ways to increase thebond strength and make its response lessbrittle after failure.(5) More R&D is needed on frost uplift reductiondevices for P6. piles.D. General Design and Performance(I) A number of methods for foundation designin permafrost have been proposed, but thesystematic verification of their predlctionsagainst the performance of foundationsunder controlled conditions isstill scarce. In addition, it is not yetclear how to determine relevant frozensoil parameters that properly representlong-term soil behavior without performingvery long-term creep tests.(2) Pile design under cyclic and dynamicloads needs further improvement.(3) Extrapolation of full-scale loading testresults to long-term performance shouldbe investigated.(4) Static cone and push-in pressuremeter devicesare promising for getting the basicinformation needed for pile design inoffshore permafrost. They can becomepractically useful only if they are usedmore frequently and their predictions arecompared with actual pile performance.ACICNOWLEDGMENTA portion of the bibliographical data presentedin this report was drawn from an earlierliterature review (Ref. P35) made by the authorfor the National Research Council of Canada.BIBLIOGRAPHY (1963-1983)I. Piles and Deep FootingsP1. Johnston, G.H., 1966, Pile constructionin permafrost, Proceedings of theFirst International Conference on Permafrost,Purdue University, 1963: Washington,D.C., National Academy of Sciences,p. 477-481,P2. Crory, F.E., 1966, Pile foundations inpermafrost, Proceedings of the FirstInternational Conference on Permafrost,Purdue University, 1963: Washington,D.C., National Academy of Sciences, p.467-472.P3. Crory, P.E., 1965, Pile foundations indiscontinuous permafrost areas, & Proceedingsof the Canadian Regional Perma-P7.P8.P9.P10.Pll.PI 2.P13.P14.P15.frost Conference, Edmonton: Ottawa, NationalResearch Council of Canada, TechnicalMemorandum No. 86, p. 58-76.Crory, P.E. and mtlock, C.S., 1967,Piles in permafrost for bridge foundations.ASCE Structural Engineering Conference:Seattle, Preprint 522.Crory, F.E., 1968, Bridge foundations inpermafrost areas, Goldstream Creek,Fairbanks, Alaska: Hanover, N.H. , U.S.Army Cold Regions Research and EngineeringLaboratory, Technical Report 180, AD667945.Sanger, F.J., 1969, Foundations ofstructures in cold regions: Hanover,N.H. , U.S. Army Cold Regions Researchand Engineering Laboratory, MonographIII-C4, AD 694371.Miller, J.M., 1971, Pile Eoundations inthermally fragile frozen soils, Proceedingsof the Symposium on Cold RegionsEngineering: University of Alaska,Fairbanks, V. 1, p. 34-72.Watson, G.H. and Rowley, R.K., 1972, Inuvikpile load tests: Mackenzie ValleyPipe Line Research Ltd., Internal Report.Rowley, R.K., Watson, G.H. , and Ladanyi,B., 1973, Vertical and lateral pile loadtests in permafrost, & Permafrost --the North American Contribution to theSecond International bnference, Yakutsk:Washington, LC., National Academyof Sciences, p. 712-721.Crory, F.E., 1973, Installation of driventest piles in permafrost at BethelAir Force Station, Alaska: Hanover,N.H. , U. S. Army Cold Regions Researchand Engineering Laboratory, TechnicalReport 139, AD 774291.Linell, K.A. and Johnston, G.H., 1973,Engineering design and construction inpermafrost regions: A review, in Permafrost-- the North American Contributionto the Second International Conference,Yakutsk: Washington, D.C., NationalAcademy of Sciences, p. 553-575.Long, E.L., 1973, Designing frictionpiles for increased stability at lowerinstalled cost in permfrost, Permafrost-- the North American Contributionto the Second International Conference,Yakutsk: Washington, D.C., NationalAcademy of Sciences, p. 693-699.Ladanyi, B. and Johnston, G.H., 1974,Behavior of circular footings and plateanchors in permafrost. Canadian GeotechnicalJournal, V. 11, no. 4, p. 531--553.Crory, F.E., 1975, Bridge foundations inpermafrost areas: Hanover, N.H., U.S.Army Cold Regions Research and EngineeringLaboratory, Technical Report 266,ADA 013520.Ladanyi, B., 1975, Bearing capacity ofstrip footings in frozen soils. CanadfanGeotechnical Journal, V. 12, no. 3,p. 393-407.

I48P16.P17.P18.P19.P20.P21.P22.P23.P24.P25.P26.P27.P28.P29.Rowley, R.K., Watson, G.H., and Ladanyi,B., 1975, Prediction of pile performancein permafrost under lateral load. CanadianGeotechnical Journal, V. 12, no, 4,p. 510-523.Womick, O., Jr. and LeGoullon, R.B.,1975, Settling a problem of settling.Northern Engineer, V. 7, no. 1, p. 4-10.Ladanyi, B., 1976, Use of static penetrationtest in frozen soils. CanadianGeotechnical Journal, V. 13, no. 2, p.95-110.Nixon, J.F. and McRoberts. E.C., 1976, Adesign approach for pile foundations inpermafrost. Canadian Geotechnical Journal,V. 13, no. 1, p. 40-57.Rooney, J.W., Nottingham, D., and Davison,B.E., 1976, Driven H-pile foundationsin frozen sands and gravels, &Proceedings of the Second InternationalSymposium on Cold Regions Engineering,Fairbanks: University of Alaska, p.169-188.Long, E.L., 1977, Thermo-Ring Pile andThermal-Probe Foundation Systems. Anchorage,Arctic Foundations Inc.Bendz, J., 1977, Permafrost problems,beaten in pile-driving research. WesternConstruction.Nixon, J.F., 1977, First Canadian GeotechnicalColloquium: Foundation designapproaches in permafrost areas. CanadianGeotechnical Journal, V. 15, p. 96-112.Phukan, A., 1977, Pile foundations infrozen soils. Paper presented at theASME Energy Technical Conference, Houston,Texas.Long, E.L., 1978, Permafrost foundationdesigns, & Proceedings of the Cold RegionsSpecialty Conference on AppliedTechniques for Cold Environments, Anchorage,V. 2: New York, American Societyof Civil Engineers, p. 973-987.Davison, B.E., Rooney, J.W., and Bruggers,D.E., 1978, Design variables influencingpiles driven in permafrost, &Proceedings of the Cold Regions SpecialtyConference on Applied Techniques forCold Environments, Anchorage, V. 1: NewYork, American Society of Civil Engineers,p. 307-319.Myska, A.D. and How, G.T.S., 1978, Installationof pile foundations for a microwavetower system, Gillam-Churchill,Manitoba, Ifl Proceedings of the ThirdInternational Conference on Permafrost,Edmonton, v. 1: Ottawa, National ResearchCouncil of Canada, p. 826-832.Black, W.T. and Thomas, H.P., 1979, Prototypepile tests in permafrost soils,in Pipelines in Adverse Environments:State of the Art, Proceedings of theAASCE Pipeline Division Specialty Conference,New Orleans, v. I: New York,American Society of Civil Engineers, p.372-303.Tobiasson, W, and Johnson, p., 1978, Thedetails behind a typical Alaskan pileP30.P31,P32.P33.P34.P35.P36.P37.P38,P39.P40.P41.P42.foundation, 11 Proceedings of the ThirdInternational Conference on Permafrost,Edmonton, v. 1: Ottawa, National ResearchCouncil of Canada, p. 891-897.Ladanyi, B. and Paquin, J., 1978, Creepbehavior of frozen sand under a deepcircular load,& Proceedings of theThird International Conference on Pem-frost, Edmonton, v. 1: Ottawa, NationalResearch Council of Canada, p. 679-686.Phukan, A. and Andersland, O.B., 1978,Foundations for cold regions. Chapter6 in Geotechnical Engineering for ColdRegions (O.B. Andersland and Anderson,eds. ): New York, McGraw-Hill, p. 276-362.Weaver, J.S., 1979, Pile foundations inpermafrost. Edmonton, University of Alberta,Ph.D. dissertation.Johnston, G.H. (ed. ), 1980, Operation,Maintenance, and Performance of Structuresin Permafrost Engineering Designand Construction. NRCC-ACGR: Toronto,John Wiley and Sons.Morgenstern, N.R., Roggensack, W.D., andWeaver, J.S., 1980, The behaviour offriction piles in ice and ice-richsoils. Canadian Geotechnical Journal,V. 17, no. 3, p. 405-415.Ladanyi, B., 1980, Field tests of foundationsin permafrost: Literature review.Ottawa, National Research Councilof Canada, Contract OSU79-00283.Phukan, A., 1980, Design of deep Eoundationsin discontinuous permafrost. ASCEConvention and Exposition, Portland, Oregon,preprint 80-122.Linell, K.A., and Lobacz, E.F., 1980,Design and construction of foundationsin areas of deep seasonal frost and permafrost:Hanover, N.H., U.S. Army ColdRegions Research and Engineering Laboratory,Special Report 80-34, ADA 090324.Thomson, S., 1980, A brief review offoundation construction in the WesternCanadian Arctic. Quarterly Journal ofEngineering Geology, London, v. 13, p.67-76,Anon,, 1980, Adaptation of overburdendrill is ideal for piles in permafrost.Northern Development, March/April, p. 8.Thomas, H.P., and Zuscher, U., 1980, Improvementof bearing capacity of pipepiles by corrugations. Collection ofpapers from the US-Soviet Joint Seminaron Building in Cold Climates and on Permafrost,Leningrad, USSR. Hanover,N.H., U.S. Army Cold Regions Researchand Engineering Laboratory, Special Report80-40: ADA 097516, p. 229-234.Weaver, J.S., and Morgenstern, N.R.,1981, Pile design in permafrost. CanadianGeotechnical Journal, V. 18, no. 3,p. 357-370.Ladanyi, B., 1982, Determination of geotechnicalparameters of frozen soils bymeans of the cone penetration test, inProceedings, ESOFT 11: Amsterdam, V. 2,p. 223-234.

I49P43.P44.P45.P4 6.P4 7.P48,11. Deep AnchorsANI.AN2.AN3AN4.AN5.AN6._ _ ing in frozenCrow. F. ,E.. 1982. Pi1ground. Journal of Technical Councils,American Society of Civil Engineers, V.108, no. TC1, p. 112-124.Nottingham, D., and Christopherson,A.B., 1983, Driven piles in permafrost:state of the art, Proceedings of theFourth International Conference on Permafrost,Fairbanks: Washington, D.C.,National Academy of Sciences, p. 928-933,Manikian, V., 1983, Pile driving andload tests in permafrost for the KuparukPipeline System, in Proceedings of theFourth International Conference on Permafrost,Fairbanks: Washington, D.C.,National Academy of Sciences, p. 804-810.tuscher, U. , Black, W.T. , and McPhail,J.F., 1983, Results of load tests ontemperature-controlled piles in permafrost,Proceedings of the Fourth InternationalConference on Permafrost,Fairbanks: Washington, D.C., NationalAcademy of Sciences, p. 756-761,Dufour, S., Sego, D.C., and Morgenstern,N.R., 1983, Vibratory pile driving infrozen sand, 2 Proceedings of theFourth International Conference on Permafrost,Fairbanks: Washington, D.C.,National Academy of Sciences, p. 255-260.DiPasquale, L., Gerlek S., and Phukan,A., 1983, Design and construction ofpile foundations in the Yukon-KuskokwimDelta, Alaska, Proceedings of theFourth International Conference on Permafrost,Fairbanks: Washington, D.C.,National Academy of Sciences, p. 232-237.Barry, B.L, and Cormie, J.G., 1971, Constructionalaspects of the 450 KVDC NelsonRiver transmission line. ManitobaPower Conference EHV-DC, Winnipeg, p.459-492.Reinart, I., 1971, Nelson River HVDCtransmission line foundation design aspects.Manitoba Power Conference EHV-IC, Winnipeg, p. 422-440.Walt, G.L., 1971, Testing of anchors inpermafrost. Carleton University, Ottawa,M. Eng. thesis.Johnston, G.H. and Ladanyi, B., 1972,Field tests of grouted rod anchors inpermafrost. Canadian Geotechnical Journal,V. 9, no. 2, p. 176-194.EBA Engineering Consultants Ltd., 1973,Installation and testing of rod anchorsin permafrost at Norman Wells, N.W.T.Report to Canadian Arctic Gas Study Limited(unpublished).Hironka, M.C., 1974, Anchoring in snow,ice, and permafrost: Port Hueneme,California, Naval Civil Engineering Laboratory,Technical Note No. 1344.AN7. Ja lhnston. G.H.. and Ladanvi. I . B., 1974,Field tests of-deep power-installedscrew anchors in permafrost. CanadianGeotechnical Journal, V. 11, no. 3, p.348-358.AN8 Andersland, O.B., and Alwahhab, M.R.M.,1983, Lug behavior for model steel pilesin frozen sand, &Proceedings of theFourth International Conference on Permafrost,Fairbanks: Washington, D.C.,National Academy of Sciences, p, 16-21.111. Adfreeze BondAD1.AD2.AD3.AD4.AD5.Aa6.AD7 .AD8.AD9.AD1 0.AD1 1.Jellinek, H.H.G., 1959, Adhesive propertiesof ice. Journal of Colloid Science,v. 14, p. 268-280.Stehle, N.S., 1970, Holding strength ofpiles in ice: Port Hueneme, California,Naval Civil Engineering Laboratory,Technical Report R-700.Kaplar, C.W., 1971, Some strength propertiesof frozen soil and effect ofloading rate. Hanover, N.H., U.S. ArmyCold Regions Research and EngineeringLaboratory, Special Report 159, AD726913.Paige, R.A., 1974, The McMurdo icewharf, McMurdo Station, Antarctica.Bulletin of Associated Engineering Geologists,V. 11, no. 1, p. 1-14.Laba. J.T., 1974, Adfreezing of sands toconcrete. Transportation Research Record,No. 494, p. 31-39.Rice, E.F., and Ferris, W., 1976, Somelaboratory tests on creep of steel pilingin frozen ground (Summary only),Proceedings of the Second InternationalSymposium on Cold Regions Engineering,Fairbanks: University of Alaska, p,278.Paramswaran, V.R., 1978, Laboratorystudies of the adfreeze bond betweensmall-scale model piles and frozensand, & Proceedings of the Third InternationalConference on Permafrost, Edmonton,V. 1: Ottawa, National ResearchCouncil of Canada. p. 714-720.Parameswaran, V.R., 1978, Adfreezestrength of frozen sand to model piles.Canadian Geotechnical Journal, V. 15,no. 4, p. 494-500.Parameswaran, V.R., 1979, Creep of modelpiles in frozen soil. Canadian GeotechnicalJournal, v. 16, no. 1, p. 69-77.Frederking, R.M.W., 1979, Laboratorytests on dmdrag loads developed byfloating ice covers on vertical piles,in Proceedings, POAC 79, Trondheim,way, V. 2, p. 1097-1110.Nor-Parameswaran, V.R., 1981, Displacementof piles under dynamic loads in frozensoils, Proceedings of the FourthCanadian Permafrost Conference, Calgary(Roger J.E. Brown Memorial Volume, H.M.French, ed.): Ottawa, National ResearchCouncil of Canada, p. 555-559.

50IV. Frost Heave Effects on PilesFHl . Crory, F.E. and Reed, R.E., 1965, Measurementof frost heaving forces onpiles: Hanover, N.H., U.S. Army ColdRegions Research and Engineering Laboratory,Technical Report 145, AD 484955.FH2. Penner, E. and Irwin, W.W., 1969, Adfreezingof Leda clay to anchored footingcolumns. Canadian GeotechnicalJournal, V. 6, no. 3, p. 327-331.FH3 Penner, E, and Gold, L.W., 1971, Transferof heaving forces by adfreezing tocolumns and foundation walls in frostsusceptiblesoils. Canadian GeotechnicalJournal, V. 8, no. 4, p. 514-526.F84. Penner, E., 1974, Uplift forces on foundationsin frost heaving soils. CanadianGeotechnical Journal, V. 11, no. 3,p. 323-338.FH5 Domaschuk, L., 1982, Frost heave forceson embedded structural units, in Proceedingsof the Fourth Canadian PermafrostConference, Calgary: Ottawa, NationalResearch Council of Canada, p.487-496.FH6. Penner, E. and Goodrich, LE., 1983, Adfreezingstresses on steel pipe piles,Thompson, Manitoba, Proceedings ofthe Fourth International Conference onPermafrost, Fairbanks: Washington,D.C., National Academy of Sciences, p.979-983.V. Foundation MaterialsMAT1 . Ramanoff, M., 1970, Corrosion evaluationof steel test piles exposed to permafrostsoils, 2 Proceedings of the 25thConference of the National Associationof Corrosion Engineers, NBS Monograph127: Washington, D.C., U.S. Departmentof Commerce, National Bureau of Standards.MAT2. Sedziak, H.P., Shields, H.P., and Johnston,G.H., 1973, Conditions of timberfoundation piles at Inuvik, N.W.T.: Departmentof the Environment, CanadianForestry Service, Information ReportOP-X-67, 27 p.MAT3. Weaver, J.S. and Morgenstern, N.R.,1980, Considerations on the use of castin-placepiles in permafrost. CanadianGeotechnical. Journal, V. 17, no. 2, p.320-325.

Frost Heave and Ice SegregationPANEL MEMBERSEdward Penner (Chairman), Division of Building Research, National Research Council of Canada, Ottawa, CanadaS.E. Grechishchev, All-Union Research Institute of Hydrogeology and Engineering Geology, Moscw, USSRChen Xiaobai, Institute of Glaciology and Cryopedology, Academia Sinica, Lanzhou, People's Republic of ChinaRobert D. Miller, Department of Agronomy, Cornell University, Ithaca, New York, USAPeter J. Williams, Geotechnical Science Laboratories, Carleton University,Ottawa, CanadaRichard L. Berg, Cold Regions Research and Engineering Laboratory, Hanover, New Hampshire, USAINTRODUCTIONE. PennerThe selection of panel members from the USAand Canada was based on their involveuent infrost-action-related activities. S.E. Grechishchevof the USSR and Chen Xiaobai of the People'sRepublic of China were asked to describe brieflythe frost-action research in progress in theircountries. Unfortunately, the USSR representativewas not able to attend the conference, but a summaryof his paper was presented at the panel sessionby the panel chairman.Miller presents a qualitative rationalizationfor a process of thermally induced relegation, abasic ingredient of his "rigid ice model" of frostheaving. While that model purports to explainwell-known characteristics of the process, includingthe role of overburden pressure, its use forengineering purposes depends upon input functionsthat are not easily measured with the necessaryaccuracy at this time. So far, the model has beenformulated only for air-free, solute-free incompressiblesoils. He mentions (unpublished) resultsof a similitude analysis of this model whichimply that site-specific problems could be scalemodeled using a geotechnical centrifuge.Berg reviews the numerical models availablein the literature in his presentation, with particularemphasis on the difficulties encountered.His review is particularly meaningful because ofhis considerable experience in modelling with appliedengineering applications in mind.Williams deals with moisture migration infrozen zones, a subject he has studied over manyyears. The presentation states both theoreticaland experimental support of his approach to thesubject. It also provides an overall evaluationof current knowledge on the subject.The USSR and People's Republic of China panelistscover current research in their respectivecountries. Grechishchev presents his current conceptof the thennorheology of cryogenic soils,drawing attention in particular to the inseparabilityof heat, moisture, stress and strainvalues, and the phase composition of pore moisturein frozen, freezing, and thawing soils. He statesthat thermophysical and mechanical problem cannotbe resolved independently, and gives equations todescribe the interrelationship. Chen Xiaobai coverscurrent frost-action developments in the PRC,stressing engineering solutions to the frost heaveproblem. While different in detail, the approachis not unlike that followed in seasonally frozenand permafrost regions in North America. Bothcontributions will draw much attention, particularlyfrom those concerned with solutions to frostaction problem in soils.The high annual cost of frost damage to engineeringstructures as a result of the freezingof foundation soils does not appear to havebrought about a concerted, coordinated program ofresearch in any of the four countries representedon the panel. It is clear from the literaturethat important studies are being carried out, buta national foci on the problem appears to be missing.At present the research on frost action inCanada and the US4 is initiated primarily by interestedindividuals. While this certainly resultsin some excellent work, much more could beachieved if there were an organized approach. Inboth the applied aspects and numerical modellingstudies, benefits from a systematic approach wouldaccrue. The facilities and the effort expendedwould, however, have to be greatly increased tohave a real influence. This may develop as thecosta of annual damage increase.51

THE PRINCIPLES OF THERMORHEOLOGY OF CRYOGENIC SOILSS.E. Grechishchev"All-Union ResearchInstitute of Hydrogeology and Engineering GeologyMoscow. USSRIn this paper the term "cryogenic soils'' isintroduced as a shorter term for frozen, freezing,and thawing soils. Usually, thermorheology refersto a section in the mechanics of solid deformablemedia that represents the study of an interconnectionin time between mechanical stresses, strains,and temperature. However, it is necessary tobroaden the concept of thermorheology when it isapplied to cryogenic soils, because any mechanicaland thermal impact on these soils affects thephase composition of pore moisture in a complexway, namely, changes in the phase composition ofpore water lead to variations in temperature andmechanical stresses or strains. Thus, the phrasethermorheology of cryogenic soils refers to thestudy of the interconnection and interaction intime between mechanical stresses and strains, temperature,and the phase composition of pore moisturein frozen, freezing, and thawing soils. Thisphrase was first proposed by Grechishchev (1969).The thermorheology of cryogenic soils includesa consideration of the mechanical processesin soils under the impact of temperature changes,both within the range below 8'C (thermal strains,effects of an external oyerburden and unfrozenmoisture content) and with the temperature passingthrough O'C (heaving and moisture migration withfreezing, thermal settlement and consolidationwith thawing). With this approach, a combined investigationof the thermodynamic, thermophysical,physicochemical, and mechanical aspects of thecryogenic processes in soils appears necessary.The study of physical regularities and thedevelopment of physico-mathematical theories ofcryogenic processes has been intensive over thelast 20 years. Physico-mathematical models basedon Luikov's equations of heat-mass transfer haveattained the widest development in geocryology.Being theoretically elaborated to match the conditionsof phase transitions in porous media representedby soils, they were considered to be perspectivefor the investigation and the descriptionof cryogenic processes. Theoretical and experimentalworks in this field have been performed byMartynov, Tyutyunov, Chlstotinov, Feldman, Ershov,Zhestkova, Takagi, and many other Soviet and foreignspecialists. The main results and the characteristicfeature of this trend involve the establishmentof a functional interrelationship of athermal field and a moisture content field. Basically,it involves the study of the processesrelated to moisture migration under the influenceof thermal gradients; namely, changes in soil temperaturewith moisture migration movement.Although the given thermophysical trend ofstudying cryogenic processes has obvious merits,*Not present: summary presented by E.Penner.it also has a number of important limitations,which recently have become more and more evidentas new experimental data are accumulated. First,the theory of heat-mass transfer in porous media,developed by Luikov and his disciples for positivetemperatures, was less effective when applied tosubfreezing soils due to an uncertain interactionat inner interphase boundaries where the phasetransitions of pore moisture occur. Numerous attemptsto avoid this difficulty by formally definingsuch an interaction have led to physically improbableresults. The most obvious is shown byFeldman in the example of a boundary condition ofthe first type for describing moisture movement.Its use can lead to such a physically senselessconcept as a negative moisture content. Second,the theory of heat-mass transfer does not includethe mechanical phenomena that occur in soils underthe effects of moisture migration and temperaturechanges. Finally, it is the mechanical process ofsoil deformation that causes various cryogenicstructures to form in soils; these in turn determinethe occurrence of cryogenic phenomena inmacrovolurnes of soils.A mechanical trend has developed in thetheory of cryogenic processes independent of thethermophysical one. Basically it consists ofstudying a stressed-strained state of soils; temperatureand moisture content are investigated asthe independent state parameters. This approachis fruitful for a certain range of engineeringproblems. The first fundamental results In thisarea were obtained by Tsytovich, one of the foundersof geocryology, who investigated the mechanicalcharacteristics of frozen soils as well as theprocess of their settlement when thawing and formulatedthe main principles of the mechanics offrozen soil, A significant contribution to thisapproach has been made by Vyalov, who describedthe principles of soil rheology at negative temperatures.Important studies have been performedby Voitkovskii, Zaretskii, Ter-Martirosyan, Orlov,Puzakov, Anderson, Andersland, Ladanyi, Morgenstern,Chamberlain, Sayles, and others.While mentioning the important role and thevalue of investigations in mechanics of frozensoils for the development of the theory of cryogenicprocesses, it should be stated that a largepart of these processes cannot be described withinthe framework of a mechanical trend alone. In thecase of the mechanical approach, the stress-strainfield depends on temperature and moisture contentonly in a parametric way, but temperature andmoisture content themselves are stress-dependent.A certain break between the thermophysicaland the mechanical approaches to the constructionof physico-mathematical models of cryogenic processeshas taken place in developing the principlesof the theory of these processes so far. General-52

53ly, however, an interrelationship is evident betweenthe stress-strain fields, temperature, andmoisture content in soils at negative temperatures.Vyalov noted that mechanical stressesmight impact the content and migration of unfrozenmoisture in frozen soils. The most generalizedform of the dependence of unfrozen moisture contenton environmental effects (temperature, loading,etc.) is given by Tsytovich (1973) in hiswell-known principles of frozen soil mechanics:the equilibrium state of unfrozen moisture andmoisture migration when the external parameterschange. Important studies in this field have beenperformed recently by Ershov.The study of thermal strains in frozen sandyand clayey soils, started by Fedosov, who was thefirst to discover that clayey soils,instead of expanding,shrank while freezing, and by Votyakov,who experimentally established a time lag of thermalstrains after a temperature change, has playeda significant role in developing the experimentalprinciples of the thermorheology of cryogenicsoils. The lag phenomenon of thermal strains occurringafter the temperature change in soils hasbeen also established experimentally. This groupof phenomena has been called "time after-effect ofthermal strains and stresses" (Votyakov and Grechishchev,1969). Further study of thermal strainsand stresses in frozen soils has been carried onby Votyakov, Grechishchev, Shusherina, Sheshin,Rachevskii, Simagina, and others.The results of investigations on unfrozenmoisture, texture, and state of pore ice obtainedby Soviet scientists (Nersesova, Tsytovich, Andrianov,Bozhenova, Shumskii, Shvetsov, Saveliev,Dostovalov, Ananyan, Vtyurin, Pchelintsev, andothers) as well as by foreign scientists (Jumikis,Yong, Anderson, Williams, Penner, Miller, and others)are of great importance to the development ofthe thermorheology of cryogenic soils.The studies of moisture migration and frostheaving started by Taber, Beskow, Goldstein, andothers are especially significant for developingthe principles of thermorheology of cryogenicsoils. Investigations in this field have becomenumerous and they are conventionally characterizedby two approaches: the thermophysical approachincluding thermodynamics (Ananyan, Shvetsov, Chistotinov,Ivanov, Ershov, Merzlyakov, Winterkorn,Miller, Williams, Penner, Anderson, Hoekstra, andothers) and the mechanical approach (Sumgin, Tsytovich,Fedosov, Pchelintsev, Puzakov, Goldstein,Orlov, and others).Regardless of the number and the high levelof the studies mentioned, the basic problem offrozen soil physics relating to the conditions ofice crystal grtrwth and unfrozen moisture migrationin soils at negative temperatures have not yetbeen solved. Current ideas of the motive forcesof moisture migration are rather contradictory.Correlations between physical phenomena in frozensoils and the mechanical stresses and strains occurringin soils remain vague. This problem iscomplicated by the use of irreversible thermodynamicsand thermodynamic potentials for describingmoisture migration. A transition from these potentialsto stremses leads to a physically complexconception, such as "negative pore pressure (suc-tion)," which is bound to amount to thousands ofatmospheres below the ideal vacuum.Experiments to verify a new theory that wouldexplain many thermorheological phenomena in cryogenicsoils have started recently. It is based onthe study of the physicochemical, thermodynamic,and mechanical aspects of interphase interactionat the boundary of phase transitions between frozenand unfrozen zones. The following expressionsdetermining the correlations between mass flow,freezing rate, and temperature at the boundary ofphase transitions were developed by the authorfrom theoretical study of the kinetics of phaseinteraction in the'vicinity of the phase transitionboundary (Grechishchev, 1978, 1979):C2 (qw - E qs + v ~ -)LATEIT0 (Vi - Vw)P (2)where qw, qs - effective rates of flow of poremoisture and mineral particles of soil skeleton;Vi, Vw - specific phase volumes of ice and water;VE - advance rate of phase transition(freezing or thawing) boundary; ek -- the normalstress in the soil skeleton, pn - effective stressnormal to the freezing boundary; 5 - pressure inthe soil skeleton and pore water pressure; L -latent heat of water freezing; To = 273'K, ATE -Ts-Tt; TE - temperature at phase change transitionboundary, K; C1, Cp - empirical coefficientscharacterizing both the phase transition kineticsand the permeability of the phase transition zone,and decreasing with an increase in ATc; E -porosity.The following physical backgrounds are accepted,when deriving expressions (1) and (2):(a) dispersed soil heteroporosity provides a differenceover time of moisture freezing in pores ofvarious sizes; (b) occurrences of fine and coarsepores hydraulically connected and the pores inwhich the walls (represented by the surfaces ofmineral particles and ice crystals) interactthrough a water film are referred to as finepores; (c) force interaction in fine pores occursthrough the film, following the mechanism of disjoiningpressure determined by Deryagin; (d) unfrozenzone strains are subjected to the theory ofsoil consolidation; (e) full stress components indispersed soil can be represented by the sum ofeffective stresses in the mineral skeleton of soiland the pore pressure, i.e. Terzaghi's equationwhere I, k - direction of the axis, 6ik - Krone-ker delta.Expression (1) characterizes the kinetics ofphase transitions in fine pores and expression (2)that in coarse ones. As to the quantity, the proposedexpressions show that moisture flow isformed (qw 2 0, when freezing), the movement ofsoil skeleton takes place (qw < 0, when freezing),or both of them occur at the phase transition(i.e. ice and unfrozen moisture) boundary andunder the impact of the latter (term with T). Op-

54posed to this movement are an effective pressurein the soil skeleton (with coefficient Vi = 1.09cm3 g”) and the pore moisture ressure (with coefficientVi - Vu = 0.09 cm3 g-’), which areconsidered to be positive when compressing. Providedthat condition (1) for the occurrence of migrationflow qw is not satisfied (e.g. whenpressure gradient in unfrozen zone is insufficientfor moisture flow formation with freezing, necessaryfor an increase in the ice band with the givenATE), freezing occurs along the coarse poresat rate Vc, as determined by expression (2).A full system of equations for the thermorheologyof cryogenic S O i h can be constructed usingexpressions (1) and (2). For example, for thefirst approximation a phase transition zone can beregarded as a linear friction boundary betweenfrozen and unfrozen zones, and expressions (1) and(2) can be taken for the boundary conditions atthis boundary, remembering that according to Florin-Gersevanov’sequation4w - €98 = -kc grad PC (4)where kF; - effective coefficient of permeability(analogue of Darcy ‘s ratio of an imagined boundaryof freezing 6).Thus, a complete system of equations of thermorheologyof cryogenic soils nust consist of thethermoconductivity equations and equations of themechanics of deformed media for unfrozen and frozenzones of soil. These equations have turnedout to be fully combined with each other throughenvironments (a) through (d) at the freezing(thawing) boundary. Hence, the distribution ofheat, moisture, stress values, and strains in cryogenicsoils happen to be closely connected. Thisaccounts for the fact that thermophysical and mechanicalproblems cannot be solved separately inthis case.The proposed theory predicts that temperatureand pressure in pore moisture at a freezing boundarydepend completely upon the freezing conditions(i.e. the temperature of the outer boundaries andthe external overburden), pemability, and cowpressibility of soils in an unfrozen zone. Therefore,they vary constantly in the process offreezing. When considering the problem theoretically,they cannot be given in advance and they aredetermined only as a result of the solution of thewhole problem. This conclusion is born out by theexperimental data, according to which the temperatureof freezing soil is approximately proportionalto the temperature of the cold environment inwhich a soil sample is frozen.In conclusion, we can enumerate a number ofknown phenomena that can be explained with thehelp of the proposed theory in a natural way.They include: the discrepancy in phase equilibriumpressure when freezing and thawing; time-lageffect of thermal strains and stresses; hysteresisof unfrozen moisture and of volumetric strains relatedto it with cyclic freezing-thawing; discrepancyof thermal. strains parallel and perpendicularto the isotherms; occurrence of optimum coolingrates (causing extreme stress values); frozen soilvolumetric strains in time at constant temperature;discrepancy of heaving values, with soilfreezing from the surface and from the bottom, andso forth. The theory also answers the fundamentalquestion of why heaving does not occur in sandsand unsaturated clays.Further studies in the field of the thermorheology of cryogenic soils must address mechanismof formation and growth of ice bands, which is oneof the basic problem in the theory of cryolirhogenesis.REFERENCESGrechishchev, S.E., 1978, Mezhf aznoe vsaimodeistviev porovoi vlage i termoreologicheskiesvoistva merzlykh gruntov (Interphase interactionin pore moisture and thermorheologicalproperties of frozen soils): Dokl. AN SSSR,v. 242, no. 3 (in Russian).Tsytovich, N.A., 1973, Mekhanika Merzlykh Gruntov(Mechanics of Frozen Ground): Moscow, VysshayaShkola Publishers (in Russian).(Trans.) New York, McGraw-Hill, 1975, 426 p.Votyakov, I.N. and Grechishchev, S.E., 1969, 0vremennom effekte posledeistviya temperaturykhdeformatsii i napriazhenii vmerzlykh gmntakh (Time effect of thermaldeformations and stresses in frozen ground);Sb. Stroitel’stvo v Raionakh VostochnoiSibiri i Krainego Severa: Krasnoyarsk, V.14, p. 41-60 (in Russian).

CURRENT DEVELOPMENTS IN CHINA ON FROST-HEAVE PROCESSES IN SOILChen XiaobaiInstitute of Glaciology and Cryopedology, Academia SinicaLanzhou, People's Republic of ChinaINTRODUCTIONUp to now, because frost heave and Ice segregationare still important problem in civil engineeringconstruction in northeast and northwestChina, the mechanism of frost heave and water migrationand how to protect structures from frostdamage have been studied in the last few years.There has been good progress in the frostsusceptibilitycriterion of coarse-grained soils;the effect of penetration rate, surcharge stress,and depth to groundwater on frost heave; the basiccharacteristics of tangential, normal, and horizontalfrost heave forces; the effect of allowabledeformation of foundation and rheology of frozensoil on heaving force, the variation of normalheaving force under various foundation areas, andthe application value of the three heaving forces.In the last two years, the energy theory forunsaturated soil has been used to establish a modelof water migration and ice segregation in soilduring freezing, and research experiments are beingperformed both in the laboratory and in thefield.Frost heave is one of the main problems forcivil engineering and road construction in permafrostand seasonally frozen regions, t&peciallyfor hydraulic structures, which usually sufferfrost damage. In recent years, many investigatorshave studied the cryogenic process, frost heave,and the frost heave force, with special attentiongiven to field observations. The author has prepareda general review of the problem in this paper.ACTION OF FROST HEAVEBecause of the needs of engineering construction,the main factors affecting frost-heave processes,such as particle size, frost penetrationrate, effective surcharge stress, and groundwatertable, have been investigated. It is well knownthat, in saturated sand or gravel, water migrationis mainly in response to a pressure gradient.However, for clayey soil, it results from thegradient of soil water potential. The current developmentsare described below.Particle Size and GradingAccording to the current frost susceptibilitycriteria for railway construction, a frozen coarsegrainedsoil in which the content of silt-clayeyparticles is Less than 15% of the total weight doesnot consolidate during thawing. It is the author'sexperience, however, that because permafrost wasformed over a geological period, the. thawing settlementcoefficient of a frozen gravel, whose contentof silt-clayey particles is less than 2.5% ofthe total weight, is more than 12%. In an opensystem (Chen et al. 19SZ), if a saturated sandygravel with uniform grading contains more than 6%siltrclayey particles, its heave ratio will exceed1%; if the silt-clayey particle content is morethan 8-lo%, then its heave ratio will be more than2%. If the sand or gravel has a non-uniform grading,corresponding with above heave ratio, thesilt-clayey particle content is 3-4% and 6-7% oftotal, respectively, Wang (1983) indicated thatIf a coarse-grained soil contains 5% silt-clayeyparticles in open system, its average heave ratiois 1.8%.In the current "Norm of Base and FoundationDesign for Industrial and Civil Engineering Construction"(1975), fine sand Is included in thenon- or weakly frost-susceptible soil category.According to Wang's (1983) results, however, theabove criterion is not complete. Compared withthe content of 0.05-0.005 mm (X,) and 0.1-0.25 mm(X,), Wang Zhengqiu (1980) indicated that the sizeless than 0.005 mm (XI) is the most important factorinfluencing the heave ratio n of fine sand.'Ihe relationship can be expressed byn - 4.48 + 0.62X1 + 0.07X2 - 0.04X1,in which the content of 0.05-0.1 mm particles (X,)does not affect the heave ratio.me results of field observations by the Low-Temperature Construction Institute, HeilongjiangProvince, show that when a clayey soil containsmore than 50% clay particles by weight, Its permeabilityis very low and it might be classified aea weakly frost-suaceptible soil.Penetration RateThe results of Chen et al. (1981) show thatthe penetration rate strongly affects the heaveratio. When the penetration rate is less than thefirst critical limit Vfl, the ratio of frostheave I-, is very large and ice lenses are stronglysegregated. After the penetration rate exceedsthe second critical limit Vf2, however, there isalmost no water migration during freezing, and onlyin-situ pore water freezes. The relation mightbe expressed as follows:when Vfk Vf2, then 11 =segregation;when Vf2 2 Vf2 V fl,= const.; i.e. no icethen n if n' = lo + An [(1/6 - l /G)/(l/fi- 1/4q3]~; i.e. a little ice segregation;55

56when Vfvfl Ithen II = no + As + C(l/svf - l/q1); i.e. a lotof ice segregation.Effective Surcharge StressAs shm by the thermodynamic equation, thefreezing point of soil decreases with an increaoeof overburden pressure or pore water potential.Chen et al, (1983) showed that the relation betweenfreezing point drop AT and effective surchargestress p for saturated loess is AT - 0.07p. It was indicated that the increase of effectivesurcharge stress would prevent water fromflowing toward the frost front, which might beshown (for saturated loess) byln(5,/ 5uol = -aPwhere 5, is specific volumetric suction water,when p = 0, 5 = two.Because of the above relationship, under asurcharge stress the frost heave ratio TI decreasesexponentially (Chen et al,, 1983), i.e.n = rl0 exp(-bp) .Observations for clayey loam obtained in the fieldby the Low-Temperature Construction Institute,Heilongjiang Province, are the same as the author's.Xu (1981a) has studied the characteristicsof frost heave in overconsolidated, consolidated,and subconeolidated soil.Chen et al. (1983) carried out a frost heavetest of saturation Loess under loading and obtainedits shut-off pressure of about 4.6 kg/cm2.Groundwater Table-In the "Norm of Base and Foundation Design.." (19751, the critical limit of the groundwatertable is 1.5 m. However. in practice, thecapillary height of various soils is quite different.Wang Xiyao (1980, 1982) and Kong (1983) haveprovided some field results on frost heave undervarious groundwater table conditions in seasonalfrost regions. For coarse sand, fine sand, lightloam, and heavy loam, if the distance from the watertable to the frost front is more than 40, 60,120, and 160 cm, respectively, froat heave mightnot occur or it will be very weak. The distanceis very close to the critical capillary height ofthese soils.After analyzing the observed data, Zhu (1983)expressed the relation between the frost-heave ration and groundwater table H, for heavy siltloam by the following formula:TI 64.4 - 29.6 H, (N - 20, r = 0.846)Analysis of experimental and field dataa l a (1982) has given results that areabove.by Chen etclose to theFROST-HEAVE FORCEIn recent years, many investigators have givenmore attention to doing field observations ontangential, normal, and horizontal frost-heavingforces.Tangential Frost-heave ForceChen and Wu (1978) presented a summary of themain results of this subject before the mid"70s.Based on observations on the Qinghai-Xizang Plateau,Tong (1982a,b) provided its distributionwith depth. After analyzing observed data on theQinghai-Xizang Plateau, Ding Jinkang (1983) indicatedthat. under the same conditions, if the tangentialfrost-heave force for concrete foundationis taken as unity, the force for steel, stone, andwood foundations would be 1.66, 1.29, and 1.06,respectively. Assuming that a foundation is madeof concrete and the distribution of the heavingforce along its depth is uniform, Ding sug estedthat for coarse-grained soil T = 0.5 kg/cm i , andfor clayey soil T = 0.8 kg/cm2. After summarizingobservations from the Qilian Mountains, Chen(1976) divided the development process of theheaving force into slow increase, intensive increase,and relaxation; for coarse-grained soilthe last step usually does not occur. Xiao and He(1981) and Cui and Zhou (1983) did a lot of fieldobservation work from 1976 to 1978. They foundthat the maximum total tangential heave force wasalmost always measured at the permafrost table,and for clayey loam the maximum force was usuallyat a water content of about 50% by weight.The Low-Temperature Construction Instituteand the Fourth Engineering Construction and AssemblyCompany of Heilongjiang Province have investigatedthe frost-heave force in seasonally frozenregions since 1972. They found that the disrributionof tangential heaving force with depth issimilar to that of frost heave. The idea of anaverage tangential heaving force with depth is notsuitable for designing shallow foundations buriedwithin a seasonal frost layer.During freezing, if a foundation is allowedto move and is subjected to heating, the followingfactors nust be considered when determining tangentialheaving force: foundation depth, allowabledisplacement, foundation material, and the effectof heating.Normal Frost-heave ForceIt is necessary to check a structure forheave stability, if its foundation depth is notgreater than the active layer thickness, especiallyfor a hydraulic structure with a mat foundation.Based on a lot of experimental results,Chen et al. (1977, 1980a) have provided a formulafor describing the relation between normal heavingforce ui and foundation area Fi(x lo2 cm2):oi = a.+ a/Fi + b/F f

57Guan et al. (1981a) have completed a field studywith a maximum foundation area of 400 x 400 cm.Using the above formu a, they got a normal heavingforce uo = 1.75 kg/cm1 . After collecting theresults at home and abroad, Tong (1982b) gave arelation between the normal force and foundationarea F as follows:u = B F-awhere B and a are constants.Guo and Han (1982) analyzed their field observationdata collected from 1973 to 1978. Providedthat the distribution of normal frost-heaveforce with depth is very similar to that of frostheave, and the heaving force u is proportional tothe free heave of ground surface Ah, i.e.u = kAhwhere k is the coefficient of the frost-heaveforce. k was found to vary with soil types andfreezing conditions. In 1982, Guo and Han presentedthe variation of the force at differentfoundation depths.The Low-Temperature Construction Institute(1981) analyzed their observed results in relationto foundation diameters of 10, 20, 40, and 80 cm,and provided a relationship between free heaveAhhi of ground surface and total normal heavingforce Pi as follows:Pi = I *ah,They also showed that the total heaving forcedepends on diameter Di expressed as6.631N = 0.283DiAfter assuming that the deformation of the matfoundation is zero, Li and Dai (1981) provided aformula for calculating the normal force usingelastic theory. Xu et al. (1981b) suggested thatif a little deformation S of a foundation is allowable,then the heaving force u decreases exponentially,i.e.s = ae-bZhou (1983) suggested that the force u decreaseswith the increase of foundation area Fi and expressedit as follows:ubui = uo i a/FiHorizontal Frost-heave ForceIn 1966, Chen et al. measured the horizontalheaving force against a shaft wall and the sidesurface of a foundation and found the maximum tobe 2.8 kg/cm2 in the Qilian Mountains. Shen Zhongyanet al. teated horizontal forces against a retainingwal in 1972. From 1977 to 1979, DingJinkang et al. built an L-shaped model retainingwall for field observation. They measured thedisplacement and horizontal heaving forces. Itwas found that the maximum force occurred at theNmiddle of the wall or a little below for finegrainedsoil, and at the base of the wall forcoarse soil. They suggested a calculation schemefor permafrost regions with a value of 1-1.5 and0.5-1 kg/cm2 for fine-grained soil and coarse soilrespectively.Guan et al. (1981b) observed a developingprocess of horlzontal forces against a 2.8-m-highretaining wall. Because a frost crack occurred atthe top surface between the wall and soil, theheaving force was indicated to be at he base ofthe wall with a maximum of 1.25 kglcm'i. Undershallow ground-water table, Yu Mci et al. built atest retaining wall filled with wet soil with over40% moisture by weig9t. The maximum of 2.1,1.63, and 1.12 kg/cm occurred at the top, middle,and the base respectively.Countermeasures for Frost-heaveIn China it is common to prevent frost damageto a foundation by using available types of foundations.replacing clayey soil with gravel, pavinginsulator protectors, and so forth. After testingand applying these for five cycles, Ding et al.(1982) provided a comprehensive treatment usingused oil and a surface active preparation with apositive ion. With the help of the treatment, thetangential frost-heave force around the foundationwas reduced to about 5% of the original value.Water Migration andIce SegregationIn the early '60'8, because of highway constructionin cold regions, Rau Hongyen et al.(1965) suggested a method for calculating wateraccumulation in the subgrade during freezing.Chen et al. have done some experiments on watermigration in the seasonal thaw-freezing layer inthe permafrost regions of the Qilian Mountainssince 1965, and have also given more attention tothe continued growth of ice lenses at the permafrosttable.Wang Ping et al. (1982) measured water redistributionin the seasonally active layer and thepermafrost in the qilian Mountains and the Qinghai-XizangPlateau by using a neutron moisture metermade by Lanzhou University. The results showthat the water migration occurred not only in theactive layer, but also in permafrost. They alsorecommended that this rnethod could be used for determiningthe freeze-thaw boundary. The NorthwestInstitute of the Academy of Railway Sciences measuredthe dynamic equilibrium of water in soil duringfreezing on the Qinghai-Xizang Plateau withLanzhou University (1976). Their results showthat the water content, not only under the thawingboundary in the active layer but also in permafrost,usually increases in warm seasons. The effectmay extend more than 1.4 m into the permafrost,Studies have proceeded €or the following reasons:l) because as the active layer above permafrostfreezes, water migrates in the frost frontand changes into ice; 2) there is a non-equilibriummigration of unfrozen water in soil; 3) thereIs the phenomenon of material expulsion in icelens formation; and 4) because of the depositionof ground on the surface, massive ice grows year

58by year. Cheng (1983) provided a view on the fotmationof massive ground ice produced by rhythmicice segregation.Zhou Youwu, Chen et al. (1964) found a newpingo that occurred in the spring in permafrost inthe Da Xian Mountains. With the help of thetheory of moisture movement in saturated sand underpressure gradient, they suggested a successfulway to protect a railway from frost damage. Chenet al. (1979b, 1980a,b) have finished more testson the characteristics of saturated gravel duringfreezing, and have presented the relation betweenpore water pressure, an increase or decrease inthe gradient of water pressure, and the frost penetrationrate. At the same time, they suggested asatisfactory method of using a gravel bed to protectstructures from damage.In recent years, many investigators havestudied the distribution of ice lenses with depthin the field. Since 1980, using the theory of watermigration in unsaturated soil, Chen and othershave started to determine hydraulic conductivity,diffusivity, and soil water characteristic curvesat 2' and 25"C, and measured the redistribution ofwater potential with depth beneath the frostfront. They point out that there is an intensivechanging zone of soil water potential or watercontent with a range of 20-30 cm. Since 1981, Zhuet al. (1983) have established an observation stationfor determining water migration during freezingin the Zhang Yi seasonally frozen regions.Using the theory of water migration in unsaturatedsoil, Zhang and Zhu (1983) provided some formulasfor calculating the water migration during freezingfrom deep and shallow ground-water tables.Using thermo-equilibrium, moisture-equilibrium,frost-heave and state-changing equations,and analogous test criteria, Ding Dewen (1983)presented formulas for determining the criticaldepth and total thickness of ice lenses. With thehelp of the thermodynamic method, Gao and Ding(1980) provided a means of evaluating the amountof frost heave in the base course. Using the samemethod, Gao and Guo (1983) have derived a formulafor evaluating frost heave under loading.This review is only a general outline of thecurrent research into frost-heave processes insoil in China. We will continue to study the mechanismsof frost heave and ice segregation in detailin the search for viable countermeasures farfrost damage in cold regions.REFERENCES"Chen Xiaobai, 1980, Observations of frost heaveand frost-heaving force in the Jiangcan District,Qilian Shan: Journal of Glaciologyand Cryopedology, V. 2, no. 2, p. 36-40 (inChinese).Chen Xiaobai, 1981a, Frost heave of seasonally activelayer in Muli District, Qilian Mountains:&moire of Lanzhou Institute of Glaciologyand Cryopedology, Academia Sinica,no. 2, Beijing, Science Press, p. 72-81.Chen Xiaobai, 1981b, the Characteristics of thaw*This list does not contain all references citedin text.consolidation of permafrost, Mul. District,Qilian Mountains: Memoirs of Lanzhou Instituteof Glaciology and Cryopedology, AcademiaSinica, noa 2, Science Press.Chen Xiaobai and Wu Ziwang, 1978, Experimental researchon principal mechanical properties offreezing and frozen soil in China, Proceedingsof the Second Conference on Permafrost, Lanzhou.Chen Xiaobai, Tong Boliang, Ding Jinkang, and ZhouChangging, 1979a, Thirty years of research incryopedology and engineering practices inChina; Journal of Glaciology and Cryopedology,v. 1, no. 2.Chen Xiaobai, Jiang Ping, Wang Yaqing, Yu Chongyun,and Zhang Xuezhen, 1979b, On antiheavemeasure by replacing clayey soil with gravel:Kexue Tongbao (Bulletin of Science), no. 20.Chen Xiaobai, Jiang Ping, and Wang Yaqing, 1980a,A discussion of calculation method for easilydetermining normal frost-heaving force: Xydro-ElectricTechnique, no. 2.Chen Xiaobai, Jiang Ping, and Wang Yaqing, 1980b,Pore water pressure of saturated gravel duringfreezing: Journal of Glaciology and Cryopedology,v. 2, no. 4, p. 33-37.Chen Xiaobai, Jiang Ping, and Wang Yaqing, 1980c,Some characteristics of water-saturated gravelduring freezing and its applications, inProceedings of the Second International Symposiumon Ground Freezing, Trondheim: Trondhelm,Norwegian Institute of Technology, p.692-701,Chen Xiaobai, Wang Yaqing, Liu Jingsou, and YuChongyun, 1982, Preliminary study about theeffect of loading on the frost heave, Proceedingsof the Symposium on Glaciology andCryopedology held by Geographical Society ofChina (Cryopedology), Lanzhou (1978): Beijing,Science Publishing House, p, 126-127.Chen Xiaobai, Wang Yaqing, and Jiang Ping, 1983,Influence of frost penetration rate and surchargestress on frost heaving, & Proceedingsof the Second National Conference onPermafrost, Lanzhou (1981): Lanzhou, GansuPeople's Publishing House, p. 223-228.Cheng Guodong, 1983, The forming process of thicklayeredground ice: Scientia Sinica, SeriesE, V. 25, no. 3, p. 777-788.Cui Chenghan and Zhou Kaijiong, 1983, Experimentalresearch of frost heaving reaction, in Proceedingsof the Second National Conference onPermafrost, Lanzhou (1981): Lanzhou, GansuPeople's Publishing House, p. 257-264,Ding Dewen, 1983, Calculation of frost depth andmoisture condition in an open system, Proceedingsof the Second National Conference onPermafrost, Lanzhou (1981): Lanzhou, GansuPeople's Publishing House, p. 233-239.Ding Jingkang, 1981, Outdoor experimental researchon tangential frost-heaving forces, 2 Proceedingsof the Second National Conference onPermafrost, Lanzhou (1981): Lanzhou, GansuPeople's Publishing House, p. 251-256.Ding Jingkang, Zhang L., Ye C., Yan J., and Yu C.,1982, Physical and chemical methods for decreasingthe force of tangential frost-heave- in Proceedings of the National Symposium onGlaciology and Cryopedology held by the Geo-

59graphical Society of China (Cryopedology).Lanzhou (1978): Beijing, Science PublishingHouse, p. 204-206.First Design Institute of Railways, 1975, EngineeringGeology in Railway: People's RailwayPress.Gao Min and Ding Dewen, 1980, Thermodynamic methodused in the study of frost heave in naturalsoil, 1_1 Proceedings of the Second InternationalSymposium on Ground Freezing, Trondheim:Trondheim, Norwegian Institute of Technology,p. 670-679,Gao Min and Ding Dewen, 1983, Research on theamount of free frost heave of soils by thermodynamicmethod, Professional Papers on PermafrostStudies of the Qinghai-Xizang Plateau,Lanzhou: Lanzhou, Gansu People's PublishingHouse, p. 169-174.Gao Min and Guo Xinming, 1983, Thermodynamic methodin frost-heave calculation under load, eProceedings of the Second National Conferenceon Permafrost, Lanzhou (1981): Lanzhou, GansuPeople's Publishing House.Guan Fengnian, Zhou Chanqing, Ben Yongwei, andChen Xiaobai, 1981a, Experimental research ofnormal frost-heaving stress under mat foundationin situ: Journal of Glaciology and Cryopedology,v. 3, no. 3, p. 63-68 (in Chinese)Guan Fengnian, Zhou Chanqing, and Chen Xiaobai,1981b, Experimental research of horizontalfrost-heaving forces on hydraulic retainingwall, in Proceedings of the Second NationalConference on Permafrost, Lanzhou (unpublished)Guo Minzhu and Han Huanguang, 1982, Experimentalstudies of vertical heaving strength of clay,in Proceedings of the National Symposium onGlaciology and Cryopedology held by the GeographicalSociety of China (Cryopedology),Lanzhou (1978): Beijing, Science PublishingHouse, p. 120-122.Kong Qingquan, 1983, Classification of frost-heavesoil of concrete channel bed and its antiheave measure, ifl Proceedings of the SecondNational Conference on Permafrost, Lanzhou(1981): Lanzhou, Gansu People's PublishingHouse, p. 462-470.Lanzhou Institute of Glaciology, Cryopedology, andDeserts, Academia Sinica, ed., 1975, Cryopedology:Beijing, Science Publishing House.Li Anguo and Dai Jingbo, 1981, Determination ofmaximum seasonal thawing depth of the permafrostin Northeast China: Journal of Glaciologyand Cryopedology, V. 3, no. 4, p. 39-43,Liu Hongxu, 1981, On calculation of normal frostheavingforce: Journal of Glaciology andCryopedology, V. 3, no. 2, p. 13-17.Norm of Base and Foundation Design for Industrialand Civil Engineering Construction, 1975:Chinese Construction Press.Railway Ministry, 1976, Technical Standards forEngineering Construction in Railway: TrafficPress.Third Design Institute of Railways, 1979, Handbooksof Engineering Design for Railway:People's Railway Press.Tong Changjiang, 1982a, Frost heave of the soilsin the seasonal thawing layer at the FenhuoShan perma frost region in the Qinghai-XizangPlateau, 1_1 Proceedings of the Symposium onGlaciology and Cryopedology held by the GeographicalSociety of China (Cryopedology),Lanzhou (1978): Beijing, Science PubllshingHouse, p. 123-125.Tong Changjiang, 1982b, Frost-heaving force offoundation, .& Proceedings of the NationalSymposium on Glaciology and Cryopedology heldby the Geographical Society of China (Cryopedology),Lanzhou (1978): Beijing, SciencePublishing House, p. 113-119.Tong Changjiang and Yu Chongyun, 1982, On the relationshipbetween normal frost heaving forceand areas of bearing plates: Journal of Glaciologyand Cryopedology, v. 4, no. 4, p. 49--54.Wang Ping, 1982, The application of neutron moisturegauge to permafrost research, & Proceedingsof the National Symposium on Glaciologyand Cryopedology held by the GeographicalSociety of China (Cryopedology), Lanzhou(1978): Beijing, Science Publishing House,p. 109-112,Wang Xiyao, 1980, Experimental research of frostheave under different levels of ground waterin various soils: Journal of Glaciology andCryopedology, v. 2, no. 3.Wang Xiyao, 1982, Frost heave and its distributionin different layers influenced by shallowground water: Journal of Glaciology and Cryopedology,v. 4, no. 2, p. 55-62.Wang Zhengqiu, 1980, Influence of grain size constituenton frost heave in fine sand: Journalof Glaciology and Cryopedology, V. 2,no, 3, p. 24-28.Wang Zhengqiu, 1981, Classification of frost SUSceptibilityfor fine sand, Proceedings ofthe Second National Conference on Permafrost,Lanzhou (1981): Lanzhou, Gansu People's PublishingHouse, p. 218-222.Wu Ziwang, Zhang Jiayi, Wang Yaqing, and ShenZhongyan, 1981, Laboratory study of frostheaveof soils: Memoira of Lanzhou Instituteof Glaciology and Cryopedology, Academia Sinica,no. 2: Beijing, Science PublishingHouse, p. 82-96.Xiao Youming and He Chanjgeng, 1981, Research ontangential frost heaving force of piles atthe experimental houses in Jin-tao, Da Xinjganling,j& Proceedings of the Second NationalConference on Permafrost, Lanzhou (abstract):Lanzhou, Gansu People's PublishingHouse, p. 40.Xu Shaoxin, 1981a, Freezing properties of soil underdifferent consolidated states, Proceedingsof the Second National Conference onPermafrost (unpublished), Lanzhou.Xu Shaoxin, 1981b, Relationship between allowablefrost-heaving deformation and frost-heavingforces, Proceedings of the Second NationalConference on Permafrost (abstract), Lanzhou.Zhang Shixiang and Zhu Qiang, 1983, An approach tocalculation of frost heaving, & Proceedingsof the Second National Conference on Permafrost,Lanzhou (1981): Lanzhou, GansuPeople's Publishing House, p. 206-212.Zhou Chanqing, 1980, A brief introduction toachievements in the study of bases and Eoun-

60dation on frozen ground in China: Journalof Glaciology and Cryopedology, V. 2, no. 1,p. 1-5.Zhou Youcai, 1983, Analysis of the relationshipbetween frost heave and normal frost-heavingforce In clay loam and at Yangjagang, & Proceedingsof the Second National Conference onPermafrost, Lanzhou (1981): Lanzhou, EansuPeople's Publishing House, p. 245-250.Zhu Qiang, 1983, Frost-heave characteristics ofthe concrete canals in Gansu Province and themeasure of replacing subsoil, in Proceedingsof the Second National Conference on Permafrost,Lanzhou (1981): hnzhou, Gansu People'sPublishing House, p. 455-461,

THERMALLY INDUCED REGELATION: A QUALITATIVE DISCUSSIONR.D.MillerDepartment of Agronomy, Cornel1 Universityfthaca, New York, USA*P anel discu ssi on before a general audienceseems to be an appropriate occasion to offer aqualitative explanation of one distinguishing featureof one of the proposed models of frost heavein soils.What has cone to be called the rigid ice modelof frost heave exploits the assumption that aswater in soil freezes, ice forms as a continuous,inherently rigid phase that includes not only icelenses but pore ice between the lenses and, specificallyin the case of what has been called secondaryfrost heave, ice in pores on the warm side ofthe warmest ice lens. While the assumptions ofcontinuity and inherent rigidity do not appear tobe controversial, they have neither been accommodatednor exploited in models based on explanationsthat begin with ideas about ways in which atemperature gradient might induce movement of aliquid phase relative to soil grains.Essential to the rigid ice model is the conclusionthat a temperature gradient tends to inducemovements of ice and soil grains with respectto one another. Specifically, it is concludedthat when isolated grains or clusters of grainsare embedded in ice that cannot itself move, impositionof a temperature gradient induces thegrains to migrate up that gradient by a processthat has been called thermally induced regelation.If that conclusion is correct, then Newton'sThird Law implies that if ice largely fillsinterstices between a mass of grains that cannotmove, the ice will move down the temperature gradientif such movement is feasible, thereby causingfrost heave.Since the time when Taber (1930) concludedthat there mst be an adsorbed film of mobile waterthat holds a growing ice lens at a distancefrom adjacent soil grains, few have questionedthat idea. Acceptance is equivalent to acceptingthe proposition that for some reason, liquid wateris more strongly attracted by a grain surface thanis ice; there mst be an "adsorption force," realor virtual, that is felt more strongly by liquidwater than by ice. This is evidently a body forcethat acts across distances that are appreciablylarger than the lengths of chemical bonds thatwould immobilize the molecules.It may be helpful to call to mind another"grain," namely earth, which has a greater affinityfor liquid water than for an equal volume ofice at the same elevation. Thus, as the oceanfreezes, the ice formed is "held at a distance byan adsorbed film of mobile water." In the case ofthe earth grain, the attribute of liquld waterthat gives rise to preferential adsorption is themass concentration (density) of the liquid phase,which is greater than that of ice, and the mechanismof attraction is gravitation, In the case ofgrain surfaces, various attributes of the surfaces,liquid water, and ice can be suggested asoperative factors in various mechanisms; that matterwill be set aside for another occasion.Among the corwequences of preferential adsorptionof liquid water, two are important to aqualitative understanding of the process of thermallyinduced regelation. The first is that if theintensity of the force field felt by liquid waterdiminishes rapidly with distance from a grain surface,and if the amount of liquid la not enough to"fill" the potential force field, then, in thecase of a symmetrical grain, mechanical equilibriumcannot be achieved until the geographic centersof volumes of grain and water, respectively. coincide.This may be accomplished by movelnent ofeither grain or water with respect to the other,or both.This first conclusion implies that given anyconfiguration of an interface between water andsome alien substance (ice, air, or another grain),If the alien substance is less strongly attractedthan liquid, then whenever the alien substancedisplaces liquid water from the force field, thegrain and the alien substance will appear to repeleach other. This will be true if movement wouldresult in more complete filling of "adsorptionspace" close to the grain surface by liquid water.In the case of earth and its ocean, this"disjoining force" is called the buoyant force experiencedby any alien body that displaces waterfrom the "adsorbed film."The second consequence of the preferentialadsorption of liquid water relative to ice is theconclusion that when some of the water surroundinga grain is induced to freeze, the equilibriumthickness of the residual unfrozen liquid film decreasesas the temperature is lowered below O°C.This conclusion can be justified by consideringthe influence of temperature on the conditione forequilibrium between water and ice at an interface,including the role of the specific surface freeenergy (surface tension) of the interface and theinfluence of the force field on the free energiesof water and ice.If the conclusion with respect to film thicknessand temperature is accepted, and if Khere isa macroscopic thermal gradient in ice containingan occluded grain, one would expect the film to bethicker on the warn side of the grain than on thecold side. While such asymmetry is compatiblewith conditions for phase equilibrium at the film/ice interface, it is incompatible with the symmetrythat represents the condition for mechanicalequilibrium of a grain surrounded by adsorbed water.The anomaly is resolved by continuous movementof the grain relative to the rigid ice, theprocess that has been called thermally induced re-61

62gelation. Movement will be in a direction thattends to restore symmetry even though astends to be continuously maintained by melt Tt ng ry andfreezing taking place concurrently on oppositesides of the grain.The rate at which thermally induced regela-,tion takes place is governed in part by the rateat which the heat that is required to mlt ice onthe warm side and to refreeze it on the cold sidediffuses toward and away from those interfaces,locally extracting and returning sensible heat tothe mainstream of the flux of sensible heat inducedby the overall thermal gradient. The processtherefore depends, in part, on the thermalconductivities of the substances through whichheat is diffusing and on the geometries of thepathways of diffusion. These will not change mchas temperature changes. The rate of migration alsodepends, however, on viscous resistance to theflaw of water around the grain, and this will behighly dependent on film thickness. Film thicknessis inversely related to temperature. Thus,one would expect that for a given thermal gradient,migration velocity would increase as a graintravels up a temperature gradient toward the O°Cisotherm.A preliminary attempt to detect thermally inducedmigration of isolated grains produced scantyresults (Woekstra and Miller, 1967). An apparatuswas especially designed for prolonged tracking ofindividual grains and was highly successful (Emkensand Miller, 1973).As a moving grain passes through the macroscopicicelwater interface at the O°C surface,asymloetrical filling of adsorption space by waterincreases dramatically; migration should end witha spurt in velocity that drives the grain completelybeyond the 0% surface, where the forcefield can be fully occupied by liquid water.Mentally, the process described can be reoriented.Imgine, for example, that grains havebeen poured into a vessel partially filled withwater. When the grains have settled to the bottom,leaving a shallow pond of supernatant wateron top, freezing can be initiated by cooling thesurface of the pond. As the freezing front descends,ice begins to replace water within the adsorptionforce fields of the uppermost grains and,as an alien body, that ice begins to feel a repulsiveforce. (Opposite voids between the grains,the interface begins to develop convexity, an importantmatter that can be treated in terns of thesurface tension of the icelwater interface. Althoughsurface tension effects have an importantrole in the rigid ice model, they will not be discussedhere.) Continued extraction of heat willresult in continued frost heave in the mode thathas been called "primary frost heave" in which theice/watet interface does not intrude into poresbeyond the first layer of grains. Primary heavecan only be sustained if the water pressure in thepores at the base of the ice lens does not falltoo far below the pressure induced in the ice atthe base of the lens by the weight of overburden.Primary heave is reminiscent of the final stage ofexpulsion of isolated grains moving through stationaryice. In primary heave, however, It is thegrains that remain stationary while the icemoves. This is a paraphrase of the mechanism offrost heave envisioned by most scientists in WesternEurope and North America from the days of Taber(1930) through Everett (1961) and beyond.In due course it was realized that if ice intrudedinto pores below the uppermost tier ofgrains, heave would not necessarily cease, as hadbeen generally supposed. Instead of being an "anchor"to be dragged through stationary pores belowan ice lens by pressure-induced regelation, ice inthis "frozen fringe" would be driven down thethermal gradient by thermally induced regelation.Thrust developed in this process can lead to theinitiation of a new ice lens within the frozenfringe. The lens represents ice driven by thermallyinduced regelation in warmer pores, ice whichthen carries with it grains that migrate too slowlyin the colder ice to remain in contact withtheir warmer neighbors. This is what one wouldexpect if all ice were a continuous rigid body,constrained to move at uniform velocity whateverthe local temperature may be. That velocity willbe the saw as the velocity of ice in the ice lensitself, i.e., equal to the observed rate of frostheave. This is a powerful conclusion that made itpossible to formulate a mathematical model of secondaryfrost heave in term of otherwise wellknownmacroscopic equations but limited, for thetime being, to air-free, colloid-free, non-colloidalsoils (Miller, 1978).Given these equations, strategy and tacticsfor generating computer simulations of heave overtime for various boundary conditions have been developed(O'Neill and Miller, 1982) and are stillbeing Improved. Such exercises require four inputfunctions characteristic of the soil in questionbut so far, acquisition of reliable data for apriori simulations seems to be quite difficult.Hence, it may be some time before it is known whetherthe results of computer simulations will comparewell with the results of corresponding experimentalmeasurements of frost heave for a givensoil. Qualitatively, results appear to be veryencouraging (O'Neill and Miller, 1984).Gilpin (1980) paraphrased the rigid ice model(Miller, 1978) for a case in which pore ice withfrozen fringe is evidently taken to be rigid sincethe model uses a concept of lens initiation (Miller,1977) that would be valid only if that icedid indeed sustain "nonisotropic stresses." Gilpinasserts, however, that this ice is stationarywhereas lens ice is obviously moving, a velocitydiscontinuity presumably rationalized by his statedassumption that the ice does not support nonisotropicstresses at scales of time and spacerelevant to the mechanism of frost heaving. Despitethis inconsistency, his model generates simulationsof heaving that qualitatively resemblethose generated by the rigid ice model in whichmovement of pore ice is driven by thermally inducedregulation.Finally, in their book on centrifuge modelingin the construction industry, Pokrovsky andFyodorov (1968) pointed out that, in principle,simultaneous processes involving viscous flow andthermal diffusion could be modeled in a geotechnicalcentrifuge. Although they specifically mentionedprocesses involving freezing and thawing,they did not mention frost heaving. A similitudeanalysis (Miller, 1984) of processes of frost

63heaving based on the rigid ice model as well as a"capillary sink" mechanism of freezing-induced redistributionof water in moist soils suggestedthat, of various schemes for scale modeling ofsuch processes, centrifuge modeling is the mostpromising whether or not soils are air-free. solute-free,or colloid-free. In North America, thefirst attempt to test this conclusion was sponsoredby Northwest Alaska Pipeline, Inc. but ithas not been carried to completion. A new attemptis now under way at the California Institute ofTechnology.REFERENCESEverett, D.H., 1961, The thermodynamics of frostdamage to porous solids: Transactions of theFaraday Society, V. 57, p. 1541-1551,Gilpin, R.R., 1980, A model for the prediction ofice lensing and frost heave in soils: WaterResources Research, V. 16, no. 5, p. 918-930.Hoekstra, F. and Miller, R.D., 1967, On the mobilityof water molecules in the transition layerbetween ice and a solid surface: Journalof Colloid and Interface Science, v. 25, p.166-173.Miller, R.D., 1977, Lens initiation in secondaryheaving, &Proceedings of the InternationalSymposium on Frost Action in Soils, V. 2:Sweden, University of tulea, p. 68-74.Miller, R.D., 1978, Frost heaving in non-colloidalsoils, Proceedings of the Third InternationalConference on Permafrost, Edmonton,V. 1: Ottawa, National Research Council ofCanada, p. 707-713.Miller, R.D., 1984, Manuscript in preparation.O'Neill, K. and Miller, B.D., 1982, Numerical 80-lutions for a rigid-ice model of secondaryfrost heave: Hanover, N.H., U.S. Army ColdRegions Research and Engineering Laboratory,CRREL Report 82-13.O'Neill, K. and Miller. R.D., 1984, Manuscript inpreparation.Pokrovsky, G.I. and Fyodorov, I.S., 1968, Centrifugemodel testing in the construction industry:Moscow, Stroiidzat. (Trans. 1 BuildingResearch Establishment, United Kingdom, 1975.R6mkens. M.J.M., and Miller, R.D., 1973, Vibrationof mineral particles in ice with a temperaturegradient: Journal of Colloid and InterfaceScience, v. 42, p. 103-111.Taber, S., 1930, The mechanics of frost heaving:Journal of Geology, V. 38, p. 303-317.

MOISTURE MIGRATION IN FROZEN SOILSP. J, WilliamsGeotechnical Science Laboratories, Carleton UniversityOttawa, CanadaA decade or two ago it was widely assumedthat frost heave occurred because of the accumulationof water at the boundary between freezing andunfrozen soil. The idea that water might movewithin the frozen material appeared a contradictionin terms, although vapour moveent with accumulationof ice crystals in colder parts of unsaturatedsoil seemed probable. Hoekstra (1966)reported redistribution of moisture in a frozenunsaturated soil subject to a temperature gradientin excess of that to be expected due to vapourmovement. Cary and Mayland (1972) observed moistureand salt redistribution in frozen unsaturatedsoils over several weeks and explained this as beingdue to mobile unfrozen water films. Jam andNorum (1974) found little moisture migration infrozen sand and ascribed this to lack of unfrozenwater in such material. Mageau and Morgenstern(1980) reported laboratory observations of substantialmoisture movement in saturated silts between0" and -2'C. The experiments of Radd andOertle (1973) with saturated soils indicated thatfrost-heave pressure was related to the temperatureof growing ice lenses, and Goodrich and Penner's(1980) experiments confirmed this.These results imply that water passes throughsaturated frozen soil to freeze on a growinglens. They also support the applicability of afreezing temperature/pressure relationship basedon the Clausius-Clapeyron equation. The relationshiptakes account of the difference in pressurebetween the ice and water in freezing soil. Thedistribution of stresses in frozen ground is cowplex and it is evident that the pressure of theice in lenses (which equals the heaving pressure)is other than the water pressure (which constitutesthe freezing "suction"). The relationshipis discussed by many authors (notably Edlefson andAnderson, 1943); Koopmans and Miller (1966) andWilliams (1964) used it to explain unfrozen waterin frozen soil. Usually the equation is given inthe formwheredT-EdPwTVwIIdT freezing temperature, O°CdPw - pressure (suction of water)T = absolute temperatureVw = specific volume of waterR = latent heat of fusion of waterIn this form, the equation requires the assumptionthat the pressure of the ice is atmospheric.It tells us that the lower the pressureof the water in the frozen soil (i.e. the greaterthe suction), the lower the temperature. Morewidely applicable is the form:dT =(dPwVw - dPiVi) TRwhere dPi is the pressure of the ice. These relationshipsdemonstrate the gradient of potentialthat occurs along a gradient of temperature infrozen soil. Thus, water could be expected toflow to colder frozen soil at a rate depending onthe permeability of the frozen material, Theequations also facilitate analysis of migrationsof moisture due to applied stresses. Vyalov(1959) demonstrated the disappearance of ice lensesfrom a zone of high stress with enlargement oflenses outside the zone.Burt and Williams (1976) devised a permeameterfor isothermal frozen soils, applying pressureto cause water movement in and out of samples attemperatures down to -0.5OC and in one case to-5OC. Between O°C and about -O.S0C, the permeabilitycoefficients fall, at first ra idly, fromthose of unfrozen soils, to about IO-' orm s-'. Below -0.5'C the coefficients decreaseonly slowly. It is generally agreed that adjacentto the boundary of the frozen soil (the"frostline") there will be a "frozen fringe" (Penner andWalton, 1978) - and perhaps a -0.1 to -0.3'C zoneof high unfrozen water content interspersed withice, which includes growing ice lenses fed withwater from adjacent unfrozen soil. This is knmas secondary heaving (Miller, 1972), and the termis often used generally to refer to heave withinfrozen 60iL Values of hydraulic conductivity forthe frozen fringe have been derived in variousways by several authors (Horiguchi and Miller,1980; Loch, 1980) and are fairly alike, althoughgenerally not precise enough for accurate predictionof moisture transfer.An intriguing question is that of movement ofthe ice within frozen soils. hrt and Williams(1976) found that complete, transverse layers ofice did not block flw as was expected and thereforepresumably participated in it. Miller (1970)has demonstrated the movement of Ice as a regelationprocess with accretion of ice to the one sideof an ice layer and melting on the other. Thegradients of potential should be the same,but whetherboth ice and water are moving is importantfor the permeability coefficient. It is often assumedthat the permeability coefficient is closelydependent upon the amount of unfrozen water, althoughthe experimental evidence for this is uncertain.Little is known from laboratory experiments64

65about water migration and secondary heaving attemperatures of -1" or -2°C. Ratkje et al. (1982)calculate permeabilities down to -3OoC, these beingabout two orders of magnitude lower than for-0.6"C.The ultimate magnitude of heave and of heavingpressures (greater at lower temperatures) andthe phenomenon of continuing heave without furtherfrost penetration (Goto and Takahashi, 1982) areobviously related to water migration and ice accumulationwithin the frozen soil.Heaving caused by the accumulation of icewithin frozen soil occurs slowly, but it can havegreat practical significance where temperaturegradients persist for long periods. Pipelines andother structures causing long-term freezing mayexperience displacements, and very high heavingpressure may develop. Over geological time periodsthere may be much relocation of ice in permafrost(Harlan, 1974). Prediction of rates is difficult.The conventional grain size criteria forpredicting sensitivity to frost heave appear to beof little use for secondary frost heave.Theoretical analyses of secondary heave rateshave been made, for example, by Harlan (1973) andMiller et al. (1975). A procedure involving laboratoryfreezing tests and a calculation procedurebased on the concept of water migration throughthe frozen fringe has been proposed by Konrad andMorgenstern (1981).Field studies of ice accumulation (and thuswater migration) in already frozen ground suggest,in comparison with laboratory studies, remarkablylarge values (Parmzina, 1978). Mackay (1983) reportedstrain rates in already frozen groundequivalent to 7% yr-' and with measurable effectseven at -3'C. Many author6, especially in the SovietUnion, have reported increases in ice contentnear the surface of already-frozen active layers(Mackay, 1983).Because of the variation of permeability offrozen soils with temperature, most moisture mlgrationin frozen soil must involve change ofmoieture content. This implies deformation of thefrozen soil to accommodate changes in the amountof ice. The resistant strength, or creep, propertiesof the frozen ground therefore appear importantin all cases. They may well be a controllingfactor in rates of moisture dgration because ofthe effects of confining pressure (arising fromthe soil resistance), as indicated by the meltingpoint-pressure relationship when taking ice pressureand water pressures into account as discussedfor the Clausius-Clapeyron equation.REFERENCESBurt, T.P. and Williams, P.J., 1976, Hydraulicconductivity in frozen soils: Earth SurfaceProcesses, V. 1, no. 4, p. 349-360.Caw, J.W. and Mayland, H.F., 1972, Salt and watermovement in unsaturated frozen soil: SoilScience Society of America proceedings, v.36, no. 4, p. 549-555.Edlef sen, N.E. and Anderson, A.B.C., 1943, Thermodynamicsof soil moisture: Hilgardia, V. 15,no. 2, p. 31-298.Goto, S. and Takahashi, Y., 1982, Frost heave characteristicsof soil under extremely lowfrost penetration rate, Proceedings of theThird International Symposium on GroundFreezing, Hanover, New Hampshire, p. 261-268.Harlan, R.L,, 1973, Analysis of coupled heat-fluidtransport in partially frozen soil: WaterResources Research, V. 9, no. 5, p. 1314-1323.Harlan, R.L., 1974, Dynamics of water movement inpermafrost: A review, In Seminar on PermafrostHydrology: Ottawa, Canadian NationalCommittee for the International HydrologicalDecade, p. 69-77.Hoekstra, P., 1966, Moisture movement in soils undertemperature gradients with the cold-sidetemperature below freezing: Water ResourcesResearch, V. 2, no. 2, p. 241-250.Horiguchi, K. and Miller, R.D., 1980, Experimentalstudies with frozen soils in an' 'ice sandwich'permeameter: Cold Regions Science andTechnology, V. 3, no. 2,3, p. 177-183.Jame, Y., and Norum, D.I., 1976, Heat and masstransfer in freezing unsaturated soil in aclosed system, Proceedings of the SecondConference on Soil-Water Problems in Cold Regions,Edmonton, Alberta.Konrad, J.-M., and Morgenstern, N.R., 1981, Thesegregation potential of a freezing soil:Canadian Geotechnical Journal, V. 18, no. 4,p. 482-491.Koopmans, R.W.R., and Miller, R.D., 1966, Soilfreezing and soil water characteristiccurves: Soil Science Society of America Proceedings,v. 30, p. 680-685.Loch, J.P.G., 1980, Frost action in soils, stateof the art, Proceedings of the Second InternationalSymposium on Ground Freezing,Trondheim: Trondheim, Norwegian Institute ofTechnology, p. 581-596.Mackay, J.R., 1983, Downward water movement intofrozen ground, western arctic coast, Canada:Canadian Journal of Earth Sciences, v. 20,no. 1, p. 120-134.Mageau, D.W., and Morgenstern, N.R., 1980, Observationson moisture migration in frozensoils: Canadian Geotechnical Journal, V. 17,no. 1, p. 54-60.Miller, R.D., 1970, Ice sandwich: Functional semipermeablemembrane: Science, v. 169, p. 584-585.Miller, R.D., 1972, Freezing and heaving of saturatedand unsaturated soils: Highway ResearchRecord, no. 393, p. 1-11.Miller, R.D., Loch, J.P.G., and Bresler, E., 1975,Transport of water and heat in a frozen permeameter.Soil Science Society of AmericaProceedings, v. 39, no. 6, p. 1029-1036.Parmuzina, O.Y., 1978, Cryogenic texture and somecharacteristics of ice formation in the activelayer (Trans. from Problemy Kriolitologii,V. 7): Polar Geography and Geology, v.4, no, 3, 1980, p. 131-152.Penner, E., and Walton, T., 1978, Effects of temperatureand pressure on frost heaving,International Symposium on Ground Freezing(H.L. Jessberger, ed.): Bochum, Ruhr University,Germany, p. 65-72.

66Penner, E., and Coodrich, L.E., 1980, Location ofsegregated ice in frost-susceptible soil,Proceedings of the Second International Symposiumon Ground Freezing, Trondheim: Trondheim,Norwegian Institute of Technology, V.1, p. 626-639.Radd, F.J. and Oertle, D.H., 1973, Experimentalpressure studies of frost heave mechanismand the growth-fusion behavior of ice,Proceedings of the Second International Conferenceon Permafrost, Yakutsk: .Washington,D.C., National Academy of Sciences, p. 377-384.Ratkje, S.K., Yamarnoto, H., Takashi, T., Ohrai,T. and Okamoto, J, 1982, 'Ihe hydraulic conductivityof soils during frost heave:Frost 1 Jord, no. 24, p. 22-26.Vyalov, S.S., 1959, Rheological properties andbearing capacity of frozen ground (in Russian):Moscow, Izdatelstvo Akademia NaukaSSSR. (Trans. ) Hanover, N.H., U. S. Army ColdRegions Research and Engineering Laboratory,Translation 74.Williams, P.J., 1964, Unfrozen water content offrozen soils and soil moisture suction: Geotechnique,V. 14, no. 3.

STATUS OF NUMERICAL MODELS FOR HEAT AND MASS TRANSFER IN FROST-SUSCEPTIBLE SOILSR.L.BergCold Regions Research and Engineering LaboratoryHanover, New Hampshire, USATaber (1930) stated, "Freezing and thawinghave caused much damage to road pavements in coldclimates, but the processes involved have not beenclearly understood, and therefore some of the preventivemeasures adopted have proved to of be littleor no value." Although considerable time andmoney have been expended to mitigate and repairdamage due to freezing and thawing in soils, relativelylittle money has been used to develop abetter underbtanding of the complex physical,chemical, and mechanical processes that occur duringfreezing and thawing.In the last decade, most research effortshave concerned the development of mathematicalmodels coupling simultaneous fluxes of heat andwater in freezing soil-water systems. The developmentof these models has emphasized the necessityof improving our knowledge of the thermal,hydraulic, chemical, and mechanical processes involvedin freezing and thawing of soil-water systems.In most models, the soil-water system is consideredto be a macroscopic continuum. This allowsthe modellers to assume Darcian-type moistureflux and to apply equations for conservation ofmass and energy. The general equations describingheat and moisture flux and other simultaneous processesoccurring in soil-water systems have beenavailable for some time, for example, Bird et al.(1960) and Luikov (1966).The high-speed digital computer became widelyavailable in the late 1960's and early 1970's, andHarlan (1972, 1973) and Guymon and Luthin (1974)developed the earliest models of simultaneous heatand moisture flow in freezing soil-water systems.In most models, water pressures and temperaturesare the dependent variables that are computed atseveral points in time and space. Both finitedifference methods and finite element methods havebeen used to solve the resulting differentialequations in space. The finite difference methodhas been used in time.In most mathematical models, the soil-watersystem is divided into three regions:a frozen zone,a freezing zone, and- an unfrozen zone.The concepts and mathematics applied to the threeregions vary within a particular model and fromone model to another. The remainder of this paperdiscusses numerical methods used in current models;a recent paper by O'Neill (1983a) presents asimilar review of frost-heave models.mention of two-dimensional models is made in few apapers, e.g. Guymon et al. (in prep.) and Crory etal. (1982). The models require a set of initialconditions for both temperatures and pore-waterpressures (or water content) with depth. Only afew of the ,models have been applied to nonhomogeneous(layered) soil-water systems (Guymon et al.,in prep.; Crory et al., 1982). The models generallyassume zero moisture flux through the upperboundary. A time-dependent heat flux or time-dependenttemperatures may be applied to the upperboundary in most models, but the temperature conditionis usually applied. A time-dependent temperaturecondition has also normally been appliedto the lower boundary, and time-dependent pore-water pressures or moisture fluxes are applied atthe lower boundary as well.THERMAL AND HYDRAULIC PROPERTIESThe thermal and hydraulic parameters are enteredinto the models in a variety of ways and areused in a variety of algorithms. For example,constant values for the thermal conductivity offrozen and unfrozen soil-water-ice mixtures areused in some models (Outcalt, 1976), others usethe DeVries method (Berg et al., 1980; Guymon andLuthin, 1974), and others use different empiricalrelationships (Fukuda, 1982). Table 1 containsTABLE 1 Algorithms used in coupled heat and masstransfer models.Algorithm Influencing parametersHydraulic conductivity Moisture contentTemperatureSoil densityMoisture characteristic Soil densityThermal conductivity Moisture contentSoil densityTemperatureHeat capacity Moisture contentSoil densityTemperatureLatent heat of fusion Soil densityMoisture contentTemperatureINITIAL AND BOUNDARY CONDITIONSAll of the models for computing frost heavein soils are one-dimensional in space, althoughFrost heave Moisture contentOverburdenTemperatureTemperature gradientsPressure gradients

68several of the algorithms used in the models. Thetable also liars the parameters that influenceeach algorithm. Generally each model uses a differentequation, or equations, in the algorithms.Frost-heave algorithms vary from very simple toextremely complex. O'Neill (1983a) provides a moredetailed review. Results from the frost-heave algorithm"drive" the entire solution. The simplestfrost-heave algorithms use pore-water pressure,predetermined or computed in one of several ways,to cause water movement, and frost heave occurs ifthe soil becomes more than approximately 90% saturated(Berg et al., 1980; Outcalt 1976; Taylor andLuthin, 1976, 1978). In the simple models, themesh may or may not be deformed. In the complexmodels (e.g. Hopke, 1980, or O'Neill and Miller,19821, an extremely fine mesh is needed to representthe phenomena adequately, and a mesh thatmoves with the freezing zone has been used (Lynchand O'Neill, 1981).with time and position as pore-water pressureschange.The thermal conductivity may be consideredconstant in time and space, or it may vary dependingon the moisture content of the soil.None of the models allows consolidation ofthe unfrozen soil as the frozen mass reactsagainst it or as the soil dries due to moistureflux to the freezing zone.The effects of hysteresis are neglected.Nearly all of the models have been used to simulateonly a continuously freezing situation, andfreezing a soil is assumed to be analogous to dryingit. Therefore, the effects of hysteresis havenot been important. The models that have expelledwater during the early stages of freezing, i.e.Hopke (1980), O'Neill and Miller (1982), and Gilpin(19801, all assumed saturated conditions, andhysteresis is not important under conditions ofsaturated flow.FROZEN ZONEThe exact boundaries of the frozen zone dependupon the type of soil, the stress conditions,the thermal regime, and the chemical compositionof the soil water. None of the models includesmovement of chemicals or changes in the chemicalcomposition of the soil water with time or position.In models where the nodal spacing is on theorder of centimeters (e.g. Berg et al., 1980; Outcalt,1976; Dudeck and Holden, 1979), the boundariesof the frozen zone are defined by temperatures.The temperatures may be O°C or an estimatedor measured freezing point depression of thesoil water. The primary reason for this simplificationis that the nodal grid is so coarse thatthe space between two nodes may actually containan unfrozen zone, the entire freezing zone, andpart of the frozen zone.In models where the nodal spacing is on theorder of a millimeter or less, the warm-sideboundary of the frozen zone is assumed to be atthe base (warm side) of the growing ice lens.Hopke (1980) and O'Neill and Miller (1982) usethis method.The developers of most models assume no moistureflux in the frozen zone, but others relatethe hydraulic conductivity or diffusivity to thesubfreezing temperature.UNFROZEN ZONEOf the three zones, the boundaries of the unfrozenzone are the most readily defined. Unfrozensoil and water are generally assumed to occurat all temperatures greater than the freezingpoint depression of the soil water. The freezingpoint depression is normally estimated to be froma few hundredths to a few tenths of a degree belowthe freezing point of bulk water.Dempsey's (1978) model includes moisture fluxin the vapor phase, but none of the others incorporatesvapor flux. The hydraulic conductivity isgenerally related to the moisture content or porewaterpressure of the soil and is allowed to varyFREEZING ZONEThe freezing zone, or frozen fringe, Is theregion between the unfrozen zone and the frozenzone. O'Neill (1983b) defined it as "the zone overwhich the volumetric ice content increases fromzero at the freezing front to 100% (neglectingtrapped air) at the location of the warmest lens."This definition is adequate for most situations,but implies that a freezing zone does not existunless an ice lens is present. The width, orthickness, of the freezing zone is dependent uponthe unfrozen moisture content as a function oftemperature for the soil and a variety of otherfactors. Large overburden pressures, or largeloads, and small temperature gradients both tendto increase the width of the freezing zone.The most complex models, Hopke (1980), Gilpin(19801, and O'Neill and Miller (1982), use theequations proposed by Miller (1978) to model processesin the freezing zone. Very close nodalspacing is required: O'Neill and Miller (1982)used 0.025 to represent the complicated relationshipsadequately.In the less sophisticated models, where thenodal spacing is on the order of centimeters, processesin the freezing zone are included in thefrost-heave algorithm or the latent heat of fusionalgorithm. Generally, the hydraulic conductivityof the soils at subfreezing temperatures mst besomewhat arbitrarily divided by an "impedance factor"ranging from 1 to 1000 to obtain reasonableagreement between computed and observed frostheave from laboratory or field tests. No systematicroethod of estimating the impedance factor hasbeen developed.CONCLUSIONThe emphasis of this paper has been the discussionof numerical models that use coupled equationsof simultaneous heat and moisture flow. Atleast tvm other methods have recently been developedto estimate frost heave in soils (Crory etal., 1982; Konrad and Morgenstern, 1980). In bothof these methods a heat conduction model is used

69to pre dice the uosition of the 0" 'C isotherm overtime. A factor, which is dependent on the stressconditions at the O°C isotherm and is developedfrom laboratory tests on the soil, is used to computethe amount of frost heave over time. Both ofthese models eliminate the moisture flux equationsfrom the numerical model and use an empirical parameterto estimate frost heave. These approacheshave some advantages over the more complicatedcoupled heat and mass flow models.Many tests must be conducted and additionaltheories must be developed, tested, and proved beforea particular frost heave model is widely accepted.O'Neill (1983) states that "no model iscompletely successful in a strict test of frostheave prediction, or in the unequivocal verificationof any physics which has been assumed," andGuymon et al. (1983) note, "It is reasonable tostate that agreement on the complexity of frostheave models or the formulation of algorithms representingprocesses in the freezing zone is notwidespread .I*REFERENCESAitchison, G.D., ed., 1965, Moisture equilibriaand moisture changes in soils beneath coveredareas: A symposium in print: Sydney, Australia,Butterworth and Company Ltd.Anderson, D.M., and Tice, A.R., 1972, Predictingunfrozen water contents in frozen soils fromsurface area measurements: Highway ResearchBoard Bulletin 393, p, 12-18.Anderson, D.M., Tice, A.R., and &Kim, H.L, 1973,The unfrozen water and the apparent specificheat capacity of frozen soils, J Proceedingsof the Second International ConferencePermafrost, Yakutsk: Washington, D.C., NationalAcademy of Sciences, p. 289-294.Bird, R.B., Stewart, W.E., and Lightfoot, E.N.,1960, Transport phenomena: New York, JohnWiley and Sons.Cary, J.W., and Mayland, H.F., 1972, Salt and yatermovement in unsaturated frozen soil: SoilScience Society of America Proceedings, v.36, no. 4, p. 549-555.Crory, F .E., Isaacs, R.M., Penner, E., Sanger,F.J., and Shook, J.F., 1982, Designing forfrost heave conditions, preprint of a paperpresented at the AXE Spring Convention, LasVegas, Nevada.Dempsey, B.J., 1978, A mathematical model for predictingcoupled heat and water movement inunsaturated soil: International Journal forNumerical and Analytical Methods in Geomechanics,V. 2, p. 19-34.DeVries, D.A., 1952, The thermal conductivity ofsoil: Waneningen, Meded. 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VanWijk, ed.): Amsterdam, North Holland PublishingCo., p. 210-235.Dirksen, C., 1964, Water movement and frost heavingin unsaturated soil without an exKerna1source of water: Cornell University, Ph.D.dissertation (unpublished).Dirksen, C.. and Mil ler, R.D., 1966, Closed-systemfreezing of unsaturated soil: Soil ScienceSociety of America Proceedings, v. 30, p.168-173.Dudek, S.S.-M., and Holden, J.T., 1979, Theoreticalmodel €or frost heave, in Numerical Methodsin Thermal Problems (Le& and Morgan,eds.): Swansea, United Kingdom, PineridgePress, p. 216-229.Edlefson, N.E., and Anderson, A.B.C.,&1943, Thermodynamicsof soil moisture: Hilgardia, v.15, no. 2, pm 31-298.Everett, D.H., 1961, The thermodynamics of frostdamage to porous solids: Transactions of theFaraday Society, v. 57, p. 1541-1551.Fuchs, M., Campbell, G.S., and Papendick, R.I.,1978, An analysis of sensible and latent heatflow in a partially frozen unsaturated soil:Soil Science Society of America Proceedings,V. 42, p. 379-385.Fukuda, M., 1982, Experimental studies of coupledheat and moisture transfer in soils duringfreezing: Contributions from the Instituteof Low-Temperature Science, Series A, no. 31,Hokkaido University, Sapporo, Japan, p. 35-91.Eilpin, R.R., 1980, A model for the prediction ofice lensing and frost heave in soils: WaterResources Research, v. 16, no. 5, p. 918-930.Gilpin, R.R., 1979, A model of the "liquid-like"layer between ice and a substrate with applicationsto wire regelation and particle migration:Journal of Colloid and InterfaceScience, v. 68, no. 2, p. 235-251.Gray, W.G., and O'Neill, K., 1976, On the generalequations for flow in porous media and theirreduction to Darcy's Law: Water ResourcesResearch, V. 12, p. 148-154.Groenevelt, P.H., and Kay, B.D., 1974, Or! the interactionof water and heat transport in frozenand unfrozen soils: 11. 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Mathematical modelof frost heave in pavements: Hanover, N.H.,U.S. Army Cold Regions Research and EngineeringLaboratory, CRREL Report.

70Guymon, G.L., and Lu .th J.L *, 1974, A coupledheat and moisture transport model for arcticsoils: Water Resources Research, v. 10, no.5, p. 995-1001.Guymon, G.L., Berg, R.L., and Hromadka 11, T.V.,1983, Field tests of a frost-heave model, &Proceedings of the Fourth International Conferenceon Permafrost, Fairbanks: Washington,D.C., National Academy of Sciences, p.409-414.Harlan, R.L., 1972, Ground conditioning and thegroundwater response to winter conditions, inProceedings of the International Symposia o rthe Role of Snow and Ice in Hydrology, Symposiumon Properties and Processes, Banff, Alberta.Harlan, R.L., 1973, Analysis of coupled heat-fluidtransport in partially frozen soil: WaterResources Research, V. 9, no. 5, p. 1314-1323.Heastvedt, E., 1964, The interfacial energy, ice/water: Oslo, Norwegian Geotechnical Institute,Publication No. 56, p. 1-4.Hoekstra, P., 1966, Moisture movement in soils undertemperature gradients with the cold-sidetemperature below freezing: Water ResourcesResearch, v. 2, p. 241-250.Hoekstra, P., Chamberlain, E., and Frate, A.,1965, Frost-heaving pressures: Hanover,N.H., U.S. Army Cold Regions Research and EngineeringLaboratory, Research Report 176.Hopke, S., 1980, A model for frost heave includingoverburden: Cold Regions Science and Technology,v. 3, no. 213, p. 111-127.Horiguchi, K., and Miller, R.D., 1980, Experimentalstudies with frozen soils in an 'icesandwich' permeameter: Cold Regions Scienceand Technology, v. 3, no. 213, p. 177-183.International Symposium on Frost Action in Soils,1977, 16-18 February, Sweden, University ofLulea, v. 1 and 2.Jame, Y., 1978, Heat and mass transfer in freezingunsaturated soil: Saskatoon, University ofSaskatchewan, Ph.D. dissertation (unpublished).Jame, Y .W., and Norum, D.I., 1976, Heat and masstransfer in freezing unsaturated soil in aclosed system, in Proceedings of the SecondConference on Sal-Water Problems in Cold Regions,Edmonton, Alberta.Jame, Y., and Norum, D.I., 1980, Heat and masstransfer in a freezing unsaturated porousmedium: Water Resources Research, v. 16, p.811-819.Johansen, O., 1977, Frost penetration and ice accumulationin soils, &Proceedings of theInternational Symposium on Frost Action inSoils: Sweden, University of Lulea, v. 1,p. 102-111.Kay, B.D., and Groenevelt, P.H., 1974, On the interactionof water and heat transport in frozenand unfrozen soils: I. Basic theory:the vapor phase: Soil Science Society ofAmerica Proceedings, V. 38, p. 395-400.Kersten, M.S., 1949, Laboratory research for thedetermination of the thermal properties ofsoils: Hanover, N.H., U.S. Army Cold RegionsResearc :h and Engineer ing La Iboratory, ACFELTechnical Report 23, AD 712516.Keune, R., and Hoekstra, P., 1967, Calculating theamount of unfrozen water in frozen groundfrom moisture characteristic curves: Hanover,N.H., U.S. Army Cold Regions Research andEngineering Laboratory, Special Report 114.Kinosita, S., 1975, Soil-water movement and heatflux in freezing ground, Proceedings ofthe First Conference on Soil-Water Problemsin Cold Regions, Calgary, Alberta, p. 33-41.Konrad, J.-M., and Morgenstern, N.R., 1980, A mechanistictheory of ice lens formation infine-grained soils: Canadian GeotechnicalJournal, v. 17, no. 4, p. 473-486.Konrad, J.-M., and Morgenstern, N.R., 1981, Thesegregation potential of a freezing soil:Canadian Georechnical Journal, v. 18, p. 482-491Loch, J.P.G., 1978, Thermodynamic equilibrium betweenice and water in porous media: SoilScience, v. 126, no. 2, p. 77-80.Loch, J.P.G., 1980, Frost action in soils, stateof-the-art,in Proceedings of the SecondInternationai-Symposium on Ground Freezing:Engineering Geology, V. 18, p. 213-224.Loch, J.P.G., and Kay, B.D., 1978, Water redistributionin partially frozen saturated silt underseveral temperature gradients and overburdenloads: Soil Science Society of AmericaProceedings, V. 42, no. 3, p. 400-406.Low, P.F., Hoekstra, P., and Anderson, D.M., 1967,Some thermodynamic relationships for soils ator below the freezing point. Part 2: Effectsof temperature and pressure on unfrozensoil water: Hanover, N.H., U.S. Army ColdRegions Research and Engineering Laboratory,Research Report 222.Luikov, A.V., 1966, Heat and mass transfer in capillary-porousbodies (Trans. by W.B. Harrison):London, Pergamon Press.Lynch, D.R., and O'Neill, K., 1981, Continuouslydeforming finite elements for the solution ofparabolic problems, with and without phasechange: International Journal for NumericalMethods in Engineering, v. 17, p. 81-96.McGaw, R.W., and Tice, A.R., 1976, A simple procedureto calculate the volume of water remainingunfrozen in a freezing soil, in Proceedingsof the Second Conferencezil-Water Problems in Cold Regions, Edmonton, Alberta,p. 114-122.McRoberts, E.C., and Nixon, J.F., 1975, Some geotechnicalobservations on the role of surchargepressure in soil freezing, 2 ProceedingsoE the First Conference on Soil-WaterProblems in Cold Regions, Calgary, Alberta,p. 42-57.Miller, R.D., 1973, Soil freezing in relation topore water pressure and temperature, in Proceedingsof the Second International' Conferenceon Permafrost, Yakutsk: Washington,D.C., National Academy of Sciences, p. 344-352 *Miller, R.D., 1978, Frost heaving in non-colloidalsoils, 5 Proceedings of the Third InternationalConference on Permafrost. 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71Ottawa, National Research Council of Canada,V. 1, p. 708-713.Miller, R,D., 1980, Freezing phenomena in soils,Chapter 11, in Applications of Soil Physics(D. Hillel, ed.): New York, Academic Press,VI 1, p. 254-299.Miller, R.D., and KOS~OY, E.E., 1980, Computationof rate of heave versus load under quasisteadystate: Cold Regions Scienc-e and Technology,V. 3, no. 213, p. 243-251.O'Neill, K., and Miller, R.D., 1982, Numerical 80-lutions for a rigid-ice model of secondaryfrost heave: Hanover, N.H., U.S Army ColdRegions Research and Engineering Laboratory,CRREL Report 82-13.O'Neill, K., 1983a, The physics of mathematicalfrost heave models: A review: Cold RegionsScience and Technology, V. 6, no. 3, p. 275-291.O'Neill, K., 1983b, Physical and numerical studyof unsaturated heat and moisture flow: Significanceof convection: CRREL Report, in review.Outcalt, S.I., 1976, A numerical model of icelensing in freezing soils, 2 Proceedings ofthe Second Conference on Soil-Water Problemin Cold Regions, Edmonton, Alberta.Outcalt, S.I., 1980, A step function model of icesegregation, Proceedings of the Second InternationalSymposium on Ground Freezing,Trondheim: Trondheim, Norwegian Institute ofTechnology, p. 515-524.Penner, E., 1957, Soil moisture tension and icesegregation: Highway Research Board Bulletin168, p. 50-64.Penner, E., 1959, The mechanism of frost heavingin soils: Highway Research Board Bulletin225, p. 1-22.Penner, E., 1979, Effects of temperature and pressureon frost heaving: Engineering Geology,V. 16, p* 729-39.Penner, E,, and Ueda, T., 1977, The dependence offrost heaving on load application -- preliminaryresults, Proceedings of the InternationalSymposium on Frost Action in Soils:Sweden, University of Lulea, v. 1, p. 92-101.Philip, J.R., 1957, Numerical solutions of equationsof the diffusion type with diffusivityconcentration dependent. 11: AustralianJournal of Physics, v. 10, p. 29-42.Philip, J.R., 1980, Thermal field during regelation:Cold Regions Science and Technology,v. 3, no. 2,3, p. 193-203.Philip, J.R., and devries, D.A., 1957, tbisturemovement in porous materials under temperaturegradients: Transactions of the AmericanGeophysical Union, v. 38, p. 222-228.Sheppard, M. I., Kay, B.D. , and hch, J.P.G., 1978,Development and testing of a computer modelfor heat and mass flow in freezing soil, inProceedings of the Third International Conferenceon Permafrost, Edmonton, V. 1: Ottawa,National Research Council of Canada, p.75-81.Taber, S., 1930, Freezing and thawing of soils asfactors in the destruction of road pavements:Public Roads, V. 11, no. 6, p. 113-132.Takagi, S., 1978, Segregation freezing as thecause of auction force for ice lens formation:Hanover, N.H., U.S. Army Cold RegionsResearch and Engineering Laboratory, CRRELReport 78-6.Takagi, S., 1980, The adsorption force theory offrost heaving. Cold Regions Science andTechnology, V. 3, no. 1, p. 57-81.Taylor, G.S. , and Luthin, J.N., 1976, Numeric resultsof coupled heat-mss flow during freezingand thawing, Proceedings of the SecondConference on Soil-Water Problem in Cold Regions,Edmonton, p. 155-172.Taylor, G.S., and Luthin, J.N., 1978, A model forcoupled heat and moisture transfer duringsoil freezing: Canadian Geotechnical Journal,V. 15, p. 548-555.Tice, A.R., Burroue, C.M., and Anderson, D.M.,1978, Determination of unfrozen water in frozensoil by pulsed nuclear magnetic resonance,& Proceedings of the Third InternationalConference on Permafrost, Edmonton:V. 1: -Ottawa, National Research Council ofCanada, p. 149-155.Vignes, M., and Dijkema, K.N., 1974, A model forthe freezing of water in a dispersed medium:Journal of Colloidal and Interface Science,v. 49, no. 2, p. 165-172.Vignes-Adler, M., 1977, On the origin of the wateraspiration in a freezing midimu: Journal ofColloidal and Interface Science, V. 60, p.162-171.Williams, P. J., 1967, Properties and Behavior ofFreezing Soils: Oslo, Norwegian GeotechnicalInstitute.

Subsea PermafrostPANEL MEMBERSDavid M. Hopkins (Co-chairman), U.S. Geological Survey, Menlo Park, California, USAPaul V. Sellmnn (Co-Chairman), Cold Regions Research and Engineering Laboratory, Hanover, N.H., U.S.A.Steve M. Blasco, Geological Survey of Canada, Bedford Instituteof Oceanography, Dartmouth, CanadaFelix E. Are, formerly of the Permafrost Institute, Siberian Branch, Academy of Sciences, Yakutsk, USSRJames A.M. Hunter, Geological Survey of Canada, Ottawa, CanadaHans 0. Jahns, Exxon Production Research Company, Houston, Texas, USADonald W. Hayley, EBA Engineering Consultants, Ltd.,Edmonton, CanadaINTRODUCTIOND.M. Hopkins and P.V. SellmnnPermafrost, in the sense of earth materialsat temperatures below O°C, is widespread beneaththe seabed in Arctic continental shelf areas.Nevertheless, in some areas the presence of interstitialbrines and temperatures just below 0°Ccauses many seabed materials to be unfrozen or onlypartially frozen. Thus, the extent of areasunderlain by noticeably ice-bonded material ismuch more restricted than the extent of Ice-freeor partially bonded subsea permafrost.The presence of subsea permafrost on the Siberianarctic shelf was established as early as1953 (Are, 1976). In North America the first observationsand modeling were based on studies madenear Barrow, Alaska (Brewer, 1958; Lachenbruch etal., 1962; Lachenbruch, 1957) that suggested thatIce-bearing permafrost would be found only nearshore. This, combined with data from holes onshorebut near the beach at Cape Thompson, indicatedthat permafrost would be thin to absent overmuch of the remainder of the Chukchi Sea, encouraginga belief that permafrost was generally lackingbeneath the Alaskan shelves. The first evidenceof ice-bonded material beneath the CanadianBeaufort Sea probably came from the offshoredrilling program conducted by the Arctic PetroleumOperators Association (MOA) in the 1960's (Goldenet al., 1970; hckay, 1972). The existence of Isubsea permafrost beneath westernmost Beaufort Seanear Point Barrw was first established in boreholesdrilled by Lewellen (1973, 1975).Petroleum exploration in the Arctic soon precipitatedrequirements for a better understandingof subsea pennafrost. During the years 1975-1982,an ambitious governmental program of geological,geophysical, geochemical, and geotechnical studieswas mounted in advance of offshore leasing on theAlaskan segment of the Beaufort Sea shelf as partof the Outer Continental Shelf Environmental AssessmentProgram (OCSEAP) (U.S. National Oceanographicand Atmospheric Addnistration/U.S. Bureauof Land Management) of the Minerals ManagementService, then the Conservation Division of theU.S. Geological Survey. Aspects of some of thesestudies are summarized by Barnes and Hopkins(19781, Barnes (1981), and Miller and Bruggers(1980). Since the lease sales, much more detailed,more geotechnically oriented borehole programand modelling studies have been conducted byvarious petroleum companies and their consultants,In the different regulatory atmosphere of theCanadian segment of the Beaufort Sea, offshorepermfrost studies have been conducted jointly bythe Canadian government agencies and by the petroleumcompanies.The contributions of our panelists reflectthese regional differences. Sellmann and Hopkina,geologists, report ideas and concepts developedlargely during the OCSEAP studies of the Alaskanshelf. Blasco, a soils engineer, and Hunter, ageophysicist, in their separate contributions describeresults that are part of the outcome ofgovernment-industry cooperation on the Canadiansegment of the Beaufort Sea shelf. Are's briefreview of Soviet studies, of course, comes out ofstill another organizational context. Hayley is a73

74geotechnical consultant wel acquainted with boththe Alaskan and Canadian segments of the BeaufortSea shelf. Jahns, a petroleum engineer, shareswith us some of the results of his company's extensivein-house field research on the Alaskansegment of the Beaufort Sea shelf.An exciting aspect of permafrost studies inthis environment is that current investigationsare still producing surprising results. This 8%-gests that we are still in the process of understandingthe distribution, properties, and processesof permafrost in this geological setting andthat opportunltles remain for stimulating scientificand engineering studies. Specific recommendationsfor future investigations are in the individualpanelists' sections.Preparation of this panel report was supportedby the Department of Interior's Mineral ManagementService, through an interagency agreementwith the National Oceanic and Atmospheric Administration.REFERENCESAre, F.E., 1976, The Subsea Cryolithozone of theArctic Ocean, Regional and ThermophysicalStudies of Perennially Frozen Rocks in Siberia:USSR Academy of Sciences, SiberianBranch, Yakutsk Book Publishing House, p. 3-26. (Trans.) Hanover, N.H., U.S. Army ColdRegions Research and Engineering Laboratory,Draft Translation 686, 1978.Barnes, P.W. and Hopkins, D.M., eds., 1978, Geologicalsciences, in Outer Continental ShelfEnvironmental Assessment, Interim SynthesisReport; BeaufordChukchi: Boulder, Colo.,U.S. National Oceanic and Atmospheric Administrationand U.S. Bureau of Land Management,p. 101-133.Barnes, P.W., ed., 1981, Physical characteristicsof the Sale 71 area, Outer ContinentalShelf Environmental Assessment Program, BeaufortSea (Sale 71) Synthesis Report, p. 81-110.Brewer, M.C., 1958, Some results of geothermal investigationsof permafrost in northern Alaska:Transactions of the American GeophysicalUnion, V. 39, no. 1, p. 19-26.Golden, Brawner and Associates, 1970, Bottomsampling program, southern Beaufort Sea.Arctic Petroleum Operators Association, ReportNo. 3.Lachenbruch, A.H., 1957, Thermal effects of theocean on permafrost: Bulletin of the GeologicalSociety of Auerica, no. 68, p. 1515-1530.Lachenbruch, A.H., Brewer, M.C., Greene, G.W., andMarshall, B.V., 1962, Temperature in permafrost,Temperature -- Its Measurement andControl in Science and Industry: New York,Reinhold Publishing Co., v. 3, p. 791-803.Lewellen, R.I., 1973, The occurrence and characteristicsof nearshore permafroat, northernAlaska, Permafrost -- the North AmericanContribution to the Second International Conference,Yakutsk: Washington, D.C., NationalAcademy of Sciences, p. 131-136.Lewellen, R.I., 1975, The occurrence and characteristicsof subsea permafrost, northernAlaska: Arctic Institute of North America,Progress Report (AINA-ONR-454), p. 131-135.Mackay, J.R., 1972, Offshore permafrost and groundice, southern Beaufort Sea: Canadian Journalof Earth Sciences, V. 9, p. 1550-1561.Miller, D.L., and Bruggers, D.E., 1980, Soil. andpermafrost conditions in the Alaskan BeaufortSea, Ifl Proceedings of the 12th Annual OffshoreTechnology Conference, Houston, p. 325-338.

SUBSEA PERMAFROST DISTRIBUTION ON THE ALASKAN SHELFP.V. SellmannCold Regions Research and Engineering LaboratoryHanover. New Hampshire, USAD. M. HopkinsU.S. Geological SurveyMenlo Park, California, USAThe subsea permafrost environment is a uniquegeological setting that has no real analogue onland. Recent investigations in Soviet, Canadian,and American coastal waters have begun to documentits widespread distribution and the great variationin the occurrence and properties of frozenground beneath the seabed.Permafrost on Land is relatively stable, naturalchanges and modifications being associatedeither with slow climatic change or with very localphenomena. Offshore, the permafrost is moredynamic, particularly in the coastal zone whereactive coastal retreat is common. In the BeaufortSea (Pig. 11, inundation can cause a 10°C IncreaseIn the mean annual temperature of the coastal permafrost(Lachenbruch et al., 1982). This warmingcan influence a block of coastal subsea permafrostup to 600 m thick that may extend up to 30 to 40km from the shore. The size of this zone is controlledby transgression rate and shelf slope.Along the coast the ice-bonded permafrost near theseabed not only undergoes rapid warming but is alsoexposed to salt water, causing noticeable reductionin strength and possible settlement due tothaw of the shallow ground ice.AB deeper parts of the large coastal pennafrostblock warm, additional changes occur moreslowly. These may include regional settleroent,increased permeability, decomposition of hydrates,and redistribution of free gas. Even though thesechanges are slow, the rates and magnitudes aregreater than ie normally associated with perma-Itb900I6b 14 0 ‘130FIGURE 1 Index map of Alaska showing locations discussedin the text.75

76-12rFIGURE 2 Marine temperature profiles for thePrudhoe Bay region from a tentative model proposedby Lachenbruch et ale (1982). The profiles notedby time in years indicate anticipated temperaturemodification caused by the sea covering an areafor the noted period of time.frost and nonpermafrost settings. An indicationof the rate of warming in the Beaufort Sea nearPrudhoe Bay, Alaska, can be obtained from the modelshown in Figure 2. Offshore geological processesand events such as shoaling, barrier islandmigration, local scouring, and seasonal brine migrationcan influence subsea permafrost throughchanges in sea-floor temperature, water depth, andbottom-water chemistry. It is also now apparentthat in certain situations, new ice-bonded permafrostcan form in the marine environment, eventhough most offshore permafrost is relict and originatedsubaerially prior to submergence.Another contrast between land and marine permafrostsettings is the small size of the offshorezone in which noticeable seasonal freezing andthaw occur. Offshore an obvious "active layer"can only be found in very shallow water areaswhere significant seasonal freezing occurs whensea ice freezes to the bed. These shallow waterareas are also subject to substantial warming duringthe summer. In contrast to land, the offshore"active layer" may be separated from deeper, wellbondedmaterial by a layer of cold unbonded salinesediment.Noticeable seasonal freezing can also occurat the seabed in deeper water where seabed sedimentsare freshened during the summer and frozenlater in the year when cold, more saline watermoves into an area (Sellmann and Chamberlain,1979; Erik Reimnitz, pers. cmm., 1983). However,in this zone, where water depth exceeds severalmeters and seabed temperatures often vary lessthan a degree Celsius, seasonal variations areusually very subtle. If "ice-bearing" materialoccurs at the seabed, it will usually be unbondedor only partially bonded. In this zone, deep,"well-ice-bonded" permafrost, usually relict, willbe covered with a thick (10-200 m) layer of thawedsaline sediments that can contain "ice-bearing"horizons. In some cases, the "ice-bearing'' zonescan be "ice-bonded. "The properties of subsea permafrost are morevariable than those of permafrost found on land,since they are controlled not only by grain size,temperature, and ice volume, but also by the salinityof interstitial ice and pore water. Thestrength of subsea permafrost is greatly influencedby the increased salinity and higher temperatures,which weaken included ice and lower bondingforces between ice and 8011 because the bondingis affected by the small concentrations of unfrozenwater that occur on soil particle surfaceseven at temperatures several degrees Celsius belowthe freezing point of the aterial (Ogata et al.,1983). Fine-grained material containing freshpore water has a higher unfrozen water content andcorrespondingly lower strength than coarse-grainedmaterial. Increased salinity in fine-grained materialcauses strength reduction similar to thatcaused by warming, the degree of warming beingcomparable to the arnwnt the freezing temperaturewas depressed by salt. Lcw unfrozen water contentin coarse-grained materials with fresh pore watercauses the strength to increase rapidly with decreasingtemperature. However, increased salinitygreatly changes this pattern, extending strengthreductions in coarse-grained materials over a muchlarger temperature range, more similar to what OCcursin fine-grained material. In coarse-grainedmaterials with large voids, strength reductionsmay be related not only to unfrozen water but toreduction in ice strength caused by increased salinity(Edwin Chamberlain, CRREL, Hanover, N.H..pers. comm.).NOMENCLATUREThe year-round occurrence of sediments colderthan O°C at the seabed and the unbonded or partiallybonded nature of parts of this permafrostsection have created some nomenclature problems.The nomenclature issue is discussed here and certainsolutions are proposed, more to call attentionto the problems than to provide ultimate SOlutions.The definition of permafrost is based upontemperature alone, and requires only that the materialremain at temperatures below O'C from yearto year (Pdwd, 1974). Permafrost, thus defined,occurs beneath a major part of the Beaufort Seashelf, and in some coastal areas it extends fromthe seabed to depths as great as 600 rn. However,because of moderate temperatures and salt in thepore water, ice-bonded sediments that can causeengineering problems are less abundant offshore.The nomenclature problem is evident in recent literature,where some authors quite properly applythe term "permafrost" to any material colder thanO"C, independent of properties, while others applythe term only to material with noticeable ice con-

77tent and associated bonding of soil particles.New qualifiers have been used to describespecific subsea permafrost properties. Hunter(this panel) speaks, for example, of subsea materialswith seismic velocities above a specificthreshold as "acoustic permafrost." "Ice-bonded"is a qualifier used by many to describe materialcontaining ice that has sufficient bond with soilparticles to cause a noticeable increase instrength properties, compared to otherwise similarunfrozen material. "Ice-bearing" has been used bysome as a very general term to indicate that icecan be expected to occur or does occur in subseamaterial, while others have used it more specifically,indicating that ice quantity or bonding isnot sufficient to influence strength properties.Because of the complex nature of subsea permafrost,it appears that the nomenclature will bemost useful if it is simple and self-explanatory.Since the use of the term "permafrost" may be veryambiguous and has led to confusion, it should bequalified or, if unqualified, used only to indicatethat materials are below O'C. More descriptivelanguage such as "perennially frozen" wouldbe most effective. We propose that "ice bearing"be used only in a very general sense, to indicatethat ice exists in the material in some quantitywith no inference drawn concerning ice volume orproperties. "Ice-bonded," as discussed earlier,would then be a special case of "ice-bearing."More specific qualifications of bonding could include"well bonded" or "partially bonded" whereadequate information is available. "Ice-bearing''material that has no apparent bonding might be referredto as "unbonded."The bulk of the permafrost qualifiers used onland can also be used offshore, with the followingrepresenting some good examples: thaw-stable andthaw-unstable (Line11 and Kaplar, 19661, thaw-sensitiveand partially frozen (van Everdingen,1976). and ice-rich (Brawn and Kupsch, 1974).DISTRIBUTIONKnowledge of the distribution of subsea permafrostoff North American coasts is largely restrictedto the Beaufort and Chukchi Sea shelves.Hopkins (1980) and Osterkamp and Harrison (1982)report no evidence for permafrost beneath the BeringSea shelf and doubt that it will be found exceptalong the most rapidly retreating coastalsegments of Norton Sound and the northwesternmostBering Sea. No ice-bonded permafrost was foundduring drilling for placer gold near Nome or atDaniels Creek on the south coast of the SewardPeninsula.The eastern part of the Chukchi Sea is warmedby the Alaskan Current, which consists of relativelywarm Pacific and Yukon River water thatflows northward through the Bering Strait. FlorenceWeber (U.S. Geological Survey, written comm.to D.M. Hopkins, 1952) noted evidence of collapseover thawing ice wedges in shallow water off rapidlyretreating parts of the west coast of theBaldwin Peninsula in Kotzebue Sound. Subzero temperatureswere also encountered in Kotzebue Soundin nearshore boreholes drilled by Osterkamp andHarrison (1982).Subzero temperatures have been observed inthe few holes drilled in the coastal waters of theChukchi Sea (Osterkamp and Harrisan, 1982; Lachenbruchet ale, 1962; Lachenbruch, 1957). A studyof bottom temperatures and the limited boreholedata from the Chukchi Sea basin indicates thatice-bearing subsea permafrost is probably thin orabsent in most of the basin except along the coastand beneath the northernmost segment of the Chukchishelf. Even in this northern segment, it isbelieved that ice-bearing permafrost becomes thinor absent approximately a kilometer offshore (Osterkampand Harrison, 1982). No seismic evidenceof permafrost has yet been recognized on the ChukchiSea shelf (A.A. Crantz, U.S. Geological Survey,pers. comm.).The situation is quite different beneath theBeaufort Sea. Point Barrow marks an importantoceanographic boundary, with bottom waters beingmuch colder to the east. Coastal processes arealso much different to the east, since the coastlineis less stable (Hopkins and Hartz, 1978; Hopkins,1980). The erosion rate of coastal permafrostoften exceeds several meters per year alongthe Beaufort coast where Lewellen (1977) reportedan average rate of 4.7 m/yr for 68 observationpoints between Harrison Bay and Barrow. Shorttermrates as great as 30 m/yr were observed byLeffingwell (1919).Ice-bonded sediments have been observed inmany of the holes drilled in the coastal waters ofthe Beaufort Sea. The distribution varies; insome areas, ice-bonded sediments occur at depthsof 10-15 m below the seabed many kilometers fromshore. In other offshore areas, occurrence ofice-bonded sediments has been confirmed at depthsgreater than 100 rn below the seabed.Aside from Lewellen's (1973, 1975) originalborehole transects east of Point Barrow and Harrisonand Osterkamp's (1981) data off Lonely whereice-bonded sediments were observed near the seabed,most ground-truth information on subsea permafrostoff the Alaskan segment of the BeaufortSea shelf comes from the area where petroleum explorationhas been most active. This includes the250-km stretch of Beaufort Sea coast from CapeHalkett through Harrison Bay and Prudhoe Bay toFlaxman Island and Brownlow Point at the northwestboundary of the Arctic National Wildlife Refuge.'he information from widely spaced borehole andprobe data in this region (Osterkamp and Harrison,1976, 1982; Osterkamp and Payne, 1981; Miller andBruggers, 1980; Blouin et al., 1979; Harrison andOsterkamp, 1981; Sellmann and Chamberlain, 1979)was extended considerably by analysis of seismicdata (Neave and Sellmann, 1982, 1983, in press;Rogers and Morack, 1980; Morack and Rogers, 1982).The seismic studies, borehole and probe data,and preliminary information from extensive industrystudies suggest a patchy and irregular dlstributionof ice-bonded permafrost and the importantroles of geologic history and seabed sediment typein determining permafrost properties and distribution.The above information suggests three commondistribution patterns for ice-bonded permafrost inthe Alaskan segment of the Beaufort Sea (Pig. 3).In the first, shallow, ice-bonded permafrost nearthe seabed extends many kilometers from shore. Inthe second, material with high seismic velocities,

I78050100I so01002 nn(km)FIGURE 3 Three distribution patterns suggestedfor ice-bonded subsea permafrost based on boreholeand seismic data: (a) shallow ice-bonded, (b) deepice-bonded, and (c) layered ice-bonded materials(from Neave and Sellmann, in press).as much as 200 m below the seabed offshore, can betraced into shallow, firmly bonded material nearthe shore. The third pattern, one that may turnout to be very common when we have more detailedsubsurface information, comprises layered situations.Shallow high-velocity materials are extremelywidespread in at leaer two areas: Harrison Bayand an area off the mouth of the Sagavanirktok Rivernear Prudhoe Bay (Pig. 4 and 5). Neave andSellmann (1982) first inferred the wide distrlbutionof firmly bonded permafrost in the westernpart of Harrison Bay on the bash of analysis ofseismic data; this interpretation and an evengreater distribution of shallow ice-bonded materialwas confirmed by drilling results reported byWalker et al. (1983), who in their oral presentationindicated that firmly ice-bonded material canbe found at depths of 8 to 10 m below the seabedthroughout Harrison Bay out to the 20- isobath.Drilling has also confirmed that shallow high-velocitymaterial recognized seismlcally off theSagavanirktok River delta is firmly bonded permafrost(Miller and Bruggers, 1980).Figures 6 and 7 show examples of the secondpattern, in which the depth to strongly bondedpermafrost increases rapidly with distance fromshore. Both profiles are from the Prudhoe Bayarea but are based on different techniques. Profile6 is from analysis of seismic data presentedby Neave and Sellmann (1983); the deeper part ofthis profile was confired by offshore boreholelogs (Osterkamp and Payne, 1981). Profile 7,based on analysis of the transient electromagneticdata discussed by Ehrenbard et al. (1983) not onlyshows comparable depths to the top of bonded permafrostbut also the great depth to the bottom ofthe ice-bearing material.A Siberian example of a layered case is shownby Vigdorchik (1980, Fig. 3.13) and may be relatedto vertical differences In material properties.In the Canadian Beaufort Sea, ice-bonded coarsegrainedmaterial ia often found surrounded by unfrozenfine-grained material.Experience thus far indicates that two particularsituations are likely to generate layeredpermafrost. One situation occurs off major riverdeltas, where Holocene sequences of stratifiedsand, silt, and clay have accumulated, where theoverlying seawater may be freshened, and wherefresh groundwater may enter the most permeablestrata and freeze. The Canadian examples dis-CD0 ",I 1 I200- o, I g"3.8 km 8' 2.0AsS I -c"0 -I-c2.4 km SI- E - 2.0krnS' I--5 4":-(*I Reversed Refraction Depth -c1(01 Single Ended Refraction Depth 600 -- IILine 7-&3& "- +WE-3OOA (n) Reflection Depth -~- -t800- I I I I 1 I I I 1 I I I I l l I I I I1 l l I I I l l I 1 1 ' 1 ' I 1 I i4- I -(9)- L IReversed Refraction Velocity'0$1(0) Single Ended(a)-E 3L Reflection Velocity-Y 3;00 000hA o n 0.c- 2-PA%a$a o o o ( 3 0 0 0 0 -1 aa :A+0If I-II-SouthII I I I l l I I 1 I I I I I I I I 1 1 .0 4 8 12 16 20 24 28 32 36 40Distance (km)FIGURE 4 Profile showing the top of shallow high-velocity material in the western partof Harrison Bay interpreted to be ice-bonded permafrost (from Neave and Sellmann, 1982).

79FIGURE 5 Shaded areas A1, Bl, and C1 show the distribution of shallow high-velocity zones near HarrisonBay and Prudhoe Bay, interpreted from seismic data to be ice-bonded permafrost (from Neave and Sellmann,1983). Shallow ice-bonded material is probably also present in area B2.Distance (km)FIGURE 6 Profile of the top of deep high-velocitymaterial near Prudhoe Bay interpreted to representice-bonded permafrost, also including shallowhigh-velocity materials found farther offshorealong segments of this coastline.cussed by Hunter and by Blasco (this panel) areinfluenced by the Mackenzie River and past deltadevelopment. The stratified permafrost on the Siberianshelf illustrated by Vigdorchik (1980, Fig.3.13) may be another example of this case. AnAlaskan example is found in Harrison Bay, whichreceives the sedilaent of the Colville River, thelargest stream that enters the Alaskan segment ofthe Beaufort Sea. This layered case (shown inFig. 8) was inferred from transient electromagneticsounds near the Colville River delta and is interpretedto represent a shallow, irregular layerof Ice-bonded material over a thawed zone, bothoverlying nuch deeper ice-bonded material.The other situation consists of migratingbarrier islands and shoals, which can leave atrail of newly formed permafrost to mark theirpassage. Profile C in Figure 3 is a diagrammaticrepresentation of this mechanism. Reindeer Island(Pig. 9) may be an example of this case.The important role played by nraterial type indetermining depth to ice-bonded material is demonstratedby borehole results in Prudhoe Bay and onthe shallow shelf immediately to the north (Fig.9). There, areas underlain by overconsolidatedmarine clay dating from the last interglacialperiod are ice-bonded at depths of less than 20 m,as seen north of Reindeer Island. Ice-bonded permafrostis much deeper south of the island, lyingat depths greater than 100 m beneath a broad,shallmr trough that extends out of Prudhoe Bay andthen turns westward parallel to the presentcoast. This area is interpreted as a Pleistocenevalley carved at times when sea level was low andthe shelf was exposed. It is filled with alluvialgrave1 overlain by a few meters of soft Holocenemarine silt and clay. Evidently seawater gainedentry into the gravel during and since the drmingof the valley, destroying interstitial ice todepths of more than 100-200 m. Boreholes elsewherehave encountered older bodies of gravel.some frozen and some thawed, buried beneath lcebonded,overconsolidated clay (Miller and Bruggers,1980).Al of the Alaskan borehole data come fromthe inner shelf. The only data suggesting thepresence of ice-bonded permafrost on the middleand wter shelf come from reflection seismic datadiscussed by Neave and Sellmann (in press), Anextensive reflector 200 m below the seabed is

0 -4"" 1 '"".80-r"-+-"-""=lI I I I I I6006oooS 4000s 20005 0 2oOa N 4-N BOOON t3ooONDISTANCE [I.]FIGURE 7 Cross-section of zone interpreted to be ice-bearing based on transient electromagneticsoundings (from Ehrenbard et al., 1983).IIc SeawordI6m- X Data points7m-rnI 101 . 1 1 1 1 1 1 1 1 1 I l l I 1 112000 4000 6000 moo loo00DlStA NCE C m 1FIGURE 8 Layered ice-bearing material inferred from transient electromagnetic soundings off the ColvilleRiver delta (illustration part of oral presentation by Ehrenbard et al. [1983], provided by the courtesy ofthe authors).

81A8nbcdeRefraction dnte'lReflection dntn"Refraction dntnnDrilling, sampling, temparnture nnd chemistry data (CRREL-USGSJDrilling, mmpling, ternpernture and chemistry data"Drilling nnd samplingYDrilling"Drilling end temporatura data"Relndeer ICAYY-Ice-bondedPermafrost''BottomY0 2 4 6 8 IO 12 14 16 18 20 22Dlstance from Discovery Well (km)FIGURE 9 Variable position of top of ice-bonded permafrost controlled by variations in material type andgeological history. Illustration was based on data from a number of sources listed in Sellmann and Chamberlain(1979).thought to be traceable shoreward to a reflectorrepresenting bonded permafrost on the inner shelf.However, it rmst be acknowledged that the complexstratigraphic geometry of the inner shelf givesway seaward to an outer shelf sequence of smoothand widespread reflectors that Dinter (1982) interpretsas sandy layers formed during successivePleistocene marine transgressions; the 200- reflectornoted by Neave and Sellmann (in press) maybe one of these.The increasing literature, only some of whichis mentioned, confirms the widespread distributionand the variable nature of ice-bonded subsea permafrost.Each new detailed study provides unexpectedresults. An example is the recent discoveryof seasonal seabed freezing in areas well removedfrom the coast, and the extensive distributionof shallow Ice-bonded materials even at greatdistances from shore.REFERENCESBlouin, S.E., Chamberlain, E.J., Sellmann, P.V.,and Garfield, D.E., 1979, Determining subseapermafrost characteristics with a cone penetrometer- Prudhoe Bay, Alaska: Cold RegionsScience and Technology, V. 1, no. 1.Brown, R.J.E. , and Kupach, W.O., 1974, Permafrostterminology: Ottawa, National Research Councilof Canada, Technical Memorandum Nor 11.Dinter, D.A., 1982, Holocene marine sediments onthe middle and outer continental shelf of theBeaufort Sea north of Alaska: U.S. GeologicalSurvey Miscellaneous Investigations Series,Map I-1182-B.Ehrenbard, R.L. , Hoekstra, P. , and Rozenberg, G. ,1983, Transient electromagnetic soundings forpermafrost mapping, &Proceedings of theFourth International Conference on Permafrost,Fairbanks: Washington, D.C., NationalAcademy of Sciences, p. 272-277.Harrison, W.D. , and Osterkamp, T.E., 1981, Subseapermafrost: Probing, thermal regime and dataanalysis, Environmental Assessment of thdAlaskan Continental Shelf , Annual Reports,V. 7, p. 291-401.Hopkins, D.M. , and Hartz, R.W., 1978, Coastal morphology,coastal erosion, and barrier islandsof the Beaufort Sea, Alaska, Open File Report78-1063.Hopkins, D.M., 1980, Likelihood of encounteringpermafrost in submerged areas of northernBering Sea, Smith, P., Hartz, R. , and Hopkins,D., Offshore Permafrost Studies andShoreline History as an Aid to PredictingOffshore Permafrost Conditions: EnvironuentalAssessment of the Alaskan ContinentalShelf, Annual Report, v. 4, p. 187-193.Lachenbruch, A.H., 1957, Thermal effects of theocean on permafrost: Bulletin of the GeologicalSociety of America, no. 68, p. 1515-1530.Lachenbruch, A.H. , Brewer, M.C. , Greene, G.W.. andMarshall, B.V., 1962, Temperature in permafrost,&Temperature -- Its Measurement andControl in Science and Industry: New York,Reinhold Publishing Co., v. 3, p. 791-803.Lachenbruch, A.H., Sass, J.H., Marshall, B.V., andMoses, T.H., Jr., 1982, Permafrost, heatflow, and the geothermal regirnes of PrudhoeBay, Alaska: Journal of Geophysical Research,v. 87, no. B11, p. 9301-9316,

82Leffingwell, E, de K., 1919, The Canning River region,northern Alaska: U.S. Geological SurveyProfessional Paper 109.Lewellen, R.I., 1973, The occurrence and characteristicsof nearshore permafrost, NorthernAlaska, &Permafrost -- The North AmericanContribution to the Second International Conference,Yakutsk: washington, D.C. , NationalAcademy of Sciences, p. 131-134,Lewellen, R.I., 1975, The occurrence and characteristicsof subsea permafrost, northernAlaska: Progress Report (AINA-ONR-454), ArcticInstitute of North America, p. 131-135.Lewellen, R.I., 1977, A study of Beaufort Seacoastal erosion, northern Alaska: U.S. NationalOceanic and Atmospheric Adminlstration,Environmental Assessment of the AlaskanContinental Shelf, Annual Reports, V. 15, p.491-527.Linell, LA. and Kaplar, C.W., 1966, Descriptionand classification of frozen soih. & Permafrost,Proceedings of an International Conference,Purdue University, 1963: Washington,D.C., National Academy of Sciences, p.481-487.Miller, D.L. and Bruggers, D.E., 1980, Soil andpermafrost conditions in the Alaskan BeaufortSea, Proceedings of the 12th Annual OffshoreTechnology conference, Houston, p. 325--338.Morack, J.L. and Rogers, J.C., 1982, Marine seismicrefraction nreasurement of near-shore subseapermafrost, & Proceedings of the FourthCanadian Permafrost Conference, Calgary: Ottawa,National Research Council of Canada,p. 249-255.Neave, K.G. and SeLlmann, P.V. 1982, Subsea permafrostin Harrison Bay, Alaska: An interpretationfrom seismic data: Hanover, N.H.,U.S. Army Cold Regions Research and EngineeringLaboratory, CRREL Report 82-24.Neave, K.G. and Sellmann, P.V., 1983, Seismlc velocitiesand subsea permafrost in the BeaufortSea, Alaska, in Proceedings of the Fourth InternationalConference on Permafrost, Fairbanks:Washington, D.C., National Academy ofSciences, p. 894-898.Neave, K.C. and Sellmann, P.V., in press, Determiningdistrihtion patterns of ice-bondedpermafrost In the U.S. Beaufort Sea fromseismic data, in 'Ihe Beaufort Sea: Physicaland Biological Environment (P.W. Barnes, D.Schell and E. Reimnitz, ed. ): New York, AcademicPress.Ogata, N., Yasuda, M. and Kataoka, T., 1983, Effectsof salt concentration on strength andcreep behavior of artificially frozen soils:Cold Regions Science and Technology, v. 8,no. 2, p. 139-153.Osterkamp, T.E. and Harrison, W.D., 1976, Subseapermafrost at Prudhoe Bay, Alaska: Drillingreport and data analysis: Fairbanks, GeophysicalInstitute, University of Alaska, ReportUAG 8-247.Osterkamp, T.E. and Payne, M.W., 1981, Estimatesof permafrost thickness from well logs innorthern Alaska: Cold Regions Science andTechnology, v. 5, p. 13-27.Osterkamp, T.E. and Harrison, W.D., 1982, Tempeyaturemeasurements in subsea permafrost offthe coast of Alaska, Proceedings of theFourth Canadian Permafrost Conference, Calgary:Ottawa, National Research Council ofCanada, p. 238-248.P6w6, T.L., 1974, Permafrost: New York, EncyclopediaBritannica.Rogers, J.C. and Morack, J.L., 1980, Geophysicalevidence of shallow near-shore permafrost,Prudoe Bay, Alaska: Journal of GeophysicalResearch, v. 85, no. B9, p. 4845-4853.Sellmann, P.V. and Chamberlain, E.J., 1979, Permafrostbeneath the Beaufort Sea neat PrudhoeBay, Alaska, Proceedings of the 11th AnnualOffshore Technology Conference, Houston,p. 1481-1493.van Everdingen, R.O., 1976, Geocryological terminology:Canadian Journal of Earth Sciences,V. 13, no. 6, p. 862-867.Vigdorchik, M.E., 1980, Arctic Pleistocene historyand the development of submarine permafrost:Boulder, Colo., Westview Press.Walker, D. B.L., Hayley, D.W., and Palmer, A.C.,1983, The influence of subsea permfrost onoffshore pipeline design, Proceedings ofthe Fourth International Conference on Permafrost,Fairbanks: Washington, LC., NationalAcademy of Sciences, p. 1338-1343.

A PERSPECTIVE ON THE DISTRIBUTION OF SUBSEA PERMAFROST ON THE CANADIAN BEAUFORT CONTINENTAL SHELFS.M.BlascoGeological Survey of Canada, Bedford Institute of OceanographyDartmouth, CanadaThe distribution of permafrost in the upper100 m below the seabed on part of the CanadianBeaufort Sea shelf has been defined, based on interpretationof several thousand line kilometersof high-resolution shallow seismic profiles, correlatedwith data from approximately 90 boreholesthat encountered ice-bearing sediments (O'Connor,1981) (Pig. 1).Three types of subsea pennafrost containingice have been identified to date using analog reflectionseismic techniques: hummocky permafrost(Pig. 2), with laterally and vertically discontinuouspatches of ice-bearing sediments; stratigraphicallycontrolled permafrost (Fig. 3), wherethe occurrence of ice is controlled by bedding,and ice is found only in some layers; and marginallyice-bonded permafrost (Fig. 41, where thedistribution of ice within the sediments is solimited spatially and voluoletrically that regionalmapping of discrete horizons is difficult.The patches of hummocky permafrost appear tobe primarily associated with massive, coarsergrainedsediment (fine to medium sand), whilestratigraphically controlled permafrost is associatedwith discrete layers of sediment (sands,silts, clayey silts) that exhibit variations inice content and bonding. Marginally ice-bondedpermafrost is associated with the coarser fractionof finer-grained sedimentary sequences. In general,the distribution of shallow ice-bearing subseapermafrost is quite variable in lateral and verticalextent, being controlled by lithology, porewater salinity, and the thermal regime (Mackay,1972; Hunter et al., 1976; MacAulay and Hunter,1982)The geological history and properties of thesediments in various depositional enviromnts alsohave a major impact on distribution. Sedimentological,biostratigraphic, and seismic evidence(O'Connor, 1980; Hill et al., 1984) from the CanadianBeaufort Sea indicate that the upper 100 m ofsediment consists of a thin veneer of HoloceneMackenzie River muds that grade downward into atransgressive sequence of interlayered sands,silts, and clays of varying thickness. These sedimentslie unconfotmably upon an older complex ofglaciofluvial deltaic sedienta (Pig. 5). Radiocarbondates suggest that this entire sequence isless than 25,000 years old, and that it records arise in sea level from about 100 m below today'ss

84FIGURE 2Hummocky acoustically defined permafrost (APF).FIGURE 3Stratigraphically controlled APF.

Enhanced acousticstratigraphy suggests APF85rBorehole temperatures indicate 011sediments are permafrost affected.Visible ice noted only in samplesmFIGURE 4 Typical seismic signature where shallow sediments are marginally orpartially ice-bonded.c S hore Shelf Edge +RECENT MARINETRANSGRESSIVE {PRE-UNCONFORMITYFIGURE 5 The general geological model.level. The evidence also suggests major deltaicprogradation associated with glacial retreat, andthe formation of ice-bearing permafrost in thesesediments shortly after depoeition. At present,ice-bearing sediments are primarily found withinthe lower glaciofluvial delta complex, some 10 to20 m below the unconformity, Suggesting possibledegradation during and after the inundation ofthese sediments.Stratigraphy interpreted from the upper sectionsof conventional seismic reflection profilessuggests that within the study area the shelf hasbeen consistently delta-dominated since the lateMiocene (Willyrosen and Cote, 1982). Sedimentaryenvironments within a delta complex are many andvaried, as deposition shifts from proximal to distalregimes. In addition, with time, the seawardadvance of the delta plain over prodelta sequences

86depos its coarser-gra line d sedimen Its over f inegrainedmaterial.Permafrost in the delta complexes appears tohave formed shortly after deposition. Therefore,the occurrence and properties of ice-bearing eedimentsshould vary spatially and in degree of icebonding,depending on the properties of the depositionalenvironment at the tim of permafrostformation. Thus, subaerially exposed delta plainswith coarser-grained sediments and fresh water aremore likely to contain ice and to be well-bondedthan are fine-grained prodelta sedimnts depositedcontemporaneously under more saline shallow marineconditions. As depositional environments changedin the delta, permafrost distribution acquired itsspatial variability. During periods of lower sealevel, caused by glacial advance (either regionalor otherwise), the shelf was exposed, permittingmore extensive regional permafrost aggradation.Crustal downwarping due to the proximity of theice front may also have left the shelf covered byshallow water at various tines, limiting the possibilityof extensive or prolonged subaerial exposure.However, there is no evidence to support awidespread presence of glacier ice over the shelfduring the late Wisconsin period. If, as seemslikely, these conditions persisted through thePleistocene, the distribution of ice-bearing permafrostshould be complex throughout the entirepermafrost section.This information on permafrost distributionand properties can be utilized to evaluate the impactof subsea permafrost on engineering activities.As a result of the variation in spatialdistribution, volume of ground ice, and degree ofice-bonding within stratigraphic sequences, engineeringproblems become site-specific. From ourobservations, the permfrost section needs to beviewed as mltilayered and containing ice-bearinglayers with diverse properties. Thermal degradationof ice-bonded sediments may or may not leadto an unacceptable degree of thaw subsidence, dependingin part on the history of the substrate.Sediments that are deposited slowly and that wereexposed to repeated freeze-thaw cycles prior todeep burial may be thaw-stable, whlle similar sedimentsthat were rapidly deposited and buried withcontemporaneous growth of ground ice may not be.Perhaps through the integration of geological andgeotechnical research, specific depositional environmentsthat generate permafrost conditions thatare potentially hazardous for engineering projectscan be ident ifie d and evaluate, d. For example, ingeological settings where transgressive and relatedprocesses (such as coastal erosion) lead to theregional degradation of ice-bearing permafrost todepths of 20 to 30 m below the seabed, thaw settlementmay not have to be considered in the engineeringdesign of some projects near the seabed,such as pipelines.The incorporation of geological studies intogeotechnical investigations will assist the engineerto differentiate subsea permafrost that willhave no impact on offshore development and to recognizethe extent and severity of permafrost thatwill influence development projects.REFERENCESHill, P.R., Mudie, P. J., Moran, K.M., and Blasco,S.M., in press, A sea level curve for the CanadianBeaufort continental shelf.Hunter, J.A., Judge, A.S., MacAulay, H.A., Good,R.L. , Gagne, R.M., and Burns, R.A., 1976, Theoccurrence of permefrost and frozen sub-seabottommaterials in the Southern BeaufortSea: Geological Survey of Canada and EarthPhysics Branch, Department of Energy, Minesand Resources, Canada, Beaufort Sea Project,Technical Report No. 22.MacAuley, H.A., and Hunter, J.A., 1982, Detailedseismic refraction analysis of ice-bondedpermafrost layering in the Canadian BeaufortSea, Proceedings of the Fourth CanadianPermafrost Conference, Calgary: Ottawa, NationalResearch Council of Canada, p. 256-267.Mackay, J.R., 1972, 'Offshore permafrost and groundice, Southern Beaufort Sea: Canadian Journalof Earth Science, V. 9, p. 1550-1561.O'Connor, M.J., 1980, Development of a proposedmodel to account for the surficial geology ofthe southern Beaufort Sea: Geological Surveyof Canada, Open File Report 954.O'Connor, M. J., 1981, Distribution of shallowacoustic permafrost in the southern BeaufortSea: Geological Survey of Canada, Open FileReport 953.Willymsen, P.S., and Cote, R.P., 1982, Tertiarysedimentation in the southern Beaufort Sea,Canada: Canadian Society of Petroleum Geologists,Memoir 8, p. 43-53.

SOVIET STUDIES OF THE SUBSEA CRYOLITHOZONEF.E.Are*formerly of the Permafrost Institute, Siberian Branch, Academy of SciencesYakutsk, USSRThe emphasis of studies in the Soviet Unionhas been on the principles involved in the deve1.-opment of subsea permafroat. This information isbeing used to establish methods for predictingsubsea permafrost distribution and €or determiningits significance in relation to resource developmenton the Arctic shelf. The geocryologicalstudies made on land along the coast and on SovietArctic islands are based on borehole drilling,vertical electrical sounding, and geothermal andhydrological observations. Many boreholes havealso been drilled in the near-shore shallows.Data on the subsea cryolithozone have been obtainedin Sannikov Strait (New Siberian Islands),in Dmitri Laptev Strait, and in Van'kina Bay Inthe Laptev Sea. Information from the open oceanis obtained through geophysical studies. Conslderableemphasis is being placed on paleogeographicconsiderations and mathematical modeling of subseapermafrost development.During the Pleistocene and Holocene periods,part of the Soviet shelf was continually submergedwhile other parts alternately were submerged andemerged. During submergence, unfrozen sedimentand rocks on the shelf became saturated with seawater and frozen materials degraded. During periodsof emergence, the saline rocks and sedimentsfroze under cold continental conditions. Freezingof the saline pore fluids produced weakly mineralizedice an4 brines. At temperatures below -8'C,nslrabilite (Na2S04 - 10 H20) precipitates out ofbrines. The brines can move dmward along withthe advance of the freezing front. Present-dayground water on the shelf is similar in compositionto sea water, but it is slightly more mineralized.During regressions, syngenetlcally frozenice-rich deposits accumulated on newly exposedparts of the shelf. During transgression, thesedeposits were partly eroded in the littoral zoneand, with inundation, underwent further erosionand thaw.The mean annual temperature at the seabed dependson the water depth. In shalluw water, whereice freezes to the bottom, it Is usually negative;in water 2 to 7 m deep it may be negative OK positive;and in 7 to 200 m of water it is negative on*Not present.most parts of the shelf but higher than the freezingtemperature of the bottom sediments.The depth of thaw below the seabed at anyparticular point on the continental shelf dependsin part upon the length of time the overlyingwater column was between 2 and 7 m deep. The timerequired for the sea level to rise through thatdepth range varied at different times durlng thepost-glacial transgression and amounted to severalcenturies in some areas and one to three milleniain others. During that time, subsea permafrostdegraded partially or completely; particularly intensivethawing occurred during the Holocene climaticoptimum. Therefore, the top of frozen materialon the shelf msy be at a considerable depthbelow the seabed. However, in zones where ice canseasonally freeze to the bottom and in zones ofrecent thermoabrasion, frozen material can beclose to the seabed.In the Soviet Arctic, the temperature regimeof materials on the shelf developed in differentways. The Barents Sea shelf and a major part ofthe bra Sea shelf were never exposed, and consequentlythere IS no frozen ground. Part of thebra Sea shelf was exposed out to the present 30-misobath for two short periods during the postglacialperiod; within this part of the shelf, exceptfor the zone where ice can freeze to the bottom.the existence of relict perennially frozen layersis possible but unlikely. The most favorable conditionsfor preservation of frozen materials existon the shelves of the Laptev and East SiberianSeas, where they may occur out to about the 140-111isobath. Permafrost is absent in the southeasternpart of the Chukchi Sea, due to the positive Watertemperatures near the bottom. Along the SovietArctic coast, frozen seabed materials are widespreadin zones where ice seasonally freezes tothe bottom and within 10 to 30 km (and locally 50km) of shorelines that are rapidly retreating dueto thermoabrasion.Research priorities in future investigationswill be the study of the interaction between seawater and perennially frozen ground as controlledby geocryological, thermophyslcal, and physiochemicalparameters. An approach to this study wouldbe to investigate these parameters along a profileextending offshore from a rapidly retreating thermoabrasioncoast.87

GEOPHYSICAL TECHNIQUES FOR SUBSEAPERMAFROST INVESTIGATIONS3.A.M.HunterGeological Survey of CanadaOttawa, CanadaMuch of our knowledge of offshore permafrosthas been acquired from studies based on geophysicaltechniques. The detection of ice-bearing permafrostby geophysical wan8 is of current interestand was the subject of both formal and informaldiscussions at the Fourth International Conferenceon Permafrost.During the 1970s one of the major geophysicaltechniques used was seismic refraction. Severalpapers have been published by Canadian and USworkers on this technique for mapping ice-bearingpermafrost in the Beaufort Sea. Seismic velocitiesin unconsolidated sediments in excess of 2400m/s were assumed, on the basis of laboratory studiesin the USA, Canada, and the USSR, to representice-bonded sediment, and this velocity was used asa threshold for seismic mpplng of permafrost.This material was termed "acoustic permafrost"(APF). Often, materials with velocities less thanthe threshold value were considered "unfrozen,""non-ice-bonded," "thawed material," and so forth.Most workers realized that ice-bearing materialcontaining a lower percentage of ice than the totalpore volume might exist and, if so, would havevelocities less than 2400 m/s. However, emphasiswas placed on the higher velocity ice-bonded APF,because geophysicists tend to be conservative intheir interpreta.tions, and because it was thoughtthat high-velocity materials would be of more concerninitially to geotechnical engineering. Muchdiscussion of ice content and the velocity cutofffor ice-bonded material took place at the ThirdInternational Conference on Permafrost in Edmontonin 1978, but at that time we had little groundtruth and Lacked an adequate theoretical frameworkfor guidance.We are now able to extend our interpretationsto lower seismic velocities, 80 that over much ofthe Beaufort Sea we can substitute "possibly icebearing"for the "unfrozen zones" noted in ourearly papers. We now have more ground truth; icebearingmaterial has been recovered from stratahaving relatively lm velocities. We have alsobeen given a possible theoretical framework forthe interpretation of velocities in terms of icecontent (King, 1984).The correlation between low velocities andmaterial that may contain some ice can be illustratedwith some recent Geological Survey of Canadadata from the Canadian sector of the BeaufortSea. Our early refraction seismic work demonstratedthe presence of high-velocity ice-bondedpermafrost at depth below the seabed. The geometryof the hydrophone array was such that thenear-sea-bottom materials were often inadequatelymeasured, and for interpretation purposes the up-per "unfrozen" layer was usually assigned a velocityof 1600 m/s. During the last tm season8 wehave been measuring velocities of near-sea-bottommaterials uslng a wide-angle 12-channel reflectioneel array, specifically designed for engineeringsurveys, in conjunction with vertical incidencereflection surveys to obtain velocity Dasurementsfrom wide-angle reflections to a depth of 60 m belowthe sea bottom.Figure 1 is a compilation from 500 seismicrecords taken over a large part of the CanadianBeaufort Sea shelf. It is in the form of a twodimensionalhistogram plotting depth below seabottom vs average velocity from the sea bottom tothe reflector. The contours are in frequency ofoccurrence with a contour interval of five observations.The data are presented in this manner sothat a generalized velocity-depth function (thedashed line) can be selected for converting twowayvertical incidence travel tiroe to depth.VELOCITY (MISEC)1400 I600 laoo 2000 2400I1 f 1 iFIGURE 1 A compilation of depth vs average velocitybetween the seabed and a shallow reflector,based on 500 records from a large area in the CanadianBeaufort Sea. Contours are frequency ofoccurrence.aa

89ul-... .AA4,O -2.cI I I I I I IFraction .. .of ice1,OO0.90E 36- o,ao -.- 0.70u- 0 3.2-0,60 -WzP 0.50G 2.8-- r . ,0,4002.4- 0030.-UIVI??Oh20V1.2 c0.10iI I 1 I I I II0 10.30 0.32 0 3 0.36 0.38 0,40 0,42 0.44 0,46PorosityFIGURE 2 Theoretical curves relating conpressionalwave velocities, porosities, and fractionof ice in the pores of unconsolidated material(after King, 1984).This histogram also indirectly demonstratesthe occurrence of anomalously high velocities atshallow depths. The extremely low velocities atvery shallaw depths come from reflectors at thebase of a thin layer of fine-grained material thatblankets the shelf (unit A of S. Blaaco, perr.comm.). There are a large number of reflectors atthe depth of 17 m with an average velocity of 1600m/s; this means that the interval velocity betweenthe base of unit A and the reflectors at 17 m issomewhat higher than 1600 m/s.A large number of reflectors can also befound centered at a depth of 37 m with an averagevelocity of 1800 m/s to that depth. The actualinterval velocities between the upper reflectorsand this reflector zone are often much higher:2OOO-mIs interval velocities are not uncommon.This lower reflector grouping can be correlatedwith the top of the upper discontinuous ice-bondedlayer recognized in our refraction surveying; itis also the reflector from the various forms ofAPF recognized in our earlier reflection surveying,Thus, surficial deposits with relativelyhigh seismic velocities occur from shallow depthsdownward to the top of the APF.This raises the question as to whether thisrelatively high-velocity material represents icebearingsediments. Figure 2 is a set of theoreticalcurves from King (1984). These curves relatecompressional wave velocities, porosities, and thefraction of ice in the pores of unconsolidated materials.Notice that for the range of porositiesgiven, the "non-ice-bearing" condition is lessthan 1650 m/s. Notice also that the threshold velocityof 2400 m/s used in early refraction interpretationsto indicate ice-bonded material canbe related to 21 to 33% ice-filling of pore spacesand that, according to King (1984), ice-bearingmaterials can exist between these velocities.King notes that this model should be exteasivelytested, but employs experimental data toshow a possible linear correlation between velocityand the remaining water-filled porosity. Thisis independent of original porosity in the unfrozenstate, fraction of clay particles, or temperaturebelow O'C. King's work brings us a long waytoward establishing a firm framework to interpretseismic velocities in term of the index propertiesof perennially frozen materials.The measurement of seismic velocities frommarine or sea-bottom refraction or reflection, orby borehole seismlc mthods, should be an integralpart of future site surveying in the Beaufort Seaand in other shelf areas where permafrost conditionsprevail. An ideal site survey would combinemultidisciplinary geophysical techniques withelectromagnetic and electrical surveys and a completesuite of geophysical logs on all geotechnicalboreholes as a complement to the seismic data.It is obvious from presentations at thisFourth International Conference on Permafrost thatgreat strides have been made in the applicationand development of geophysical techniques for usein detecting and describing marine permafrost foruse in geotechnical site evaluations. The burdenis now on the geotechnical engineer to make effectiveuse of them.REFERENCEKing, M.S., 1984, The influence of clay-sized particleson seismic velocity for Canadian Arcticpermafrost: Canadian Journal of EarthSciences, v. 21, p. 19-24.

SUBSEA PERMAFROST AND PETROLEUM DEVELOPMENTH.O.JahnsExxon Production Research CompanyHouston, Texas, USAThe following comments constitute a petroleum ius and thaw subsidence for an offshore productionengineer's view of the significance of subsea per- island.mafrost in relation to two common heat sources in- I will cover the next topic, offshore pipetroducedduring offshore petroleum development:lines, in a little more detail. I briefly disproductionwells and pipelines.cussed this subject as a member of the panel onThe question is often asked -- "Since we'vepipeline construction. The result of placing asolved production well problems on shore, what'swarm pipeline in the thawed layer above ice-bondeddifferent about offshore permafrost?" On land at subsea permafrost is shown in Figure 1. As indi-Prudhoe Bay we are in fact producing through per-cated, it is assumed that the thawed zone has samafrostin a satisfactory manner using well cas-line pore water. If the pore water were fresh,ings designed to resist the stresses and strains the zone would be frozen because the man annualthat occur when the surrounding permafrost thaws. seabed temperatures are usually below O°C in theBut there are som important differences betweenBeaufort Sea. The.rate of salt migration seem tothe onshore and offshore permafrost environmentscontrol the natural degradation of offshore iceandhow they are developed. Offshore, wells will bonded permafrost (Swift et al., 1983). It is ashaveto be placed closer together, since space is sumed, therefore, that saline water replaces theat a premium on a man-made island. The resulting original pore water in the sediments.bundle of wellbores will constitute a greater heatThe natural process of salt migration andsource than the more widely spaced wells on an on- degradation of ice-bonded permafrost is alteredshore drilling pad. Consequently, there will be when we introduce a warm offshore pipeline. Asmore thaw offshore, and the thaw front will move shown in Figure 1, permafrost degradation is acfartherout from the wells. A second differencecelerated below the pipeline. Permafrost degradaisthat offshore permafrost is warmer, on average, tion can now occur without involving salt migrathanonshore permafrost. In general, the entire tion. However, the thaw rate will still be influcolumnof offshore permafrost is relatively warm, enced by the rate of salt migration within theand it can be near the freezing point of the over- thaw bulb. If salt migration is too slow to keeplying sea water. Therefore, with a given heat in- up with the advancing melt front below the pipeputthere will be more thaw in the upper portionline, then the temperature at the melt front willof the offshore permafrost zone than under other-be determined by the salinity of the original porewise comparable onshore conditions. A third dif- water. If the permafrost is essentially fresh,ference is that offshore permafrost may have athen the melting temperature will be near O'C.higher salt content. Therefore, a smaller frac- If, on the other hand, salt migration is faettion of the pore water will be frozen at a given enough to keep up with the melt front below theinitial temperature. This means that less heat is pipeline, then we will have sea-water in contactrequired to melt the pore ice.with the permafrost, and the effective meltingAs stated, the thaw bulb around the wellboreswill tend to be larger in the upper portion of thesubsea permafrost section than for typical onshore -5.-wells. Therefore, surface subsidence is expectedICESTRUDELto extend farther from the wells into areas on anisland where one would like to place productionfacilities. Another consideration is the volumechange and thaw strain that will occur within thethaw bulb. Some of the same factors that causethe thaw bulb to be larger offshore can tend toreduce the thaw strain. In areas with high permafrosttemperatures and salt contents, a smallerfraction of the pore water may be frozen, resultingin smaller volurpe change and less soil defor-SALME PORE WATER0HEAT AND SALT TRANSFERmation when a given volume of permafrost thaws.However, if relict permafrost with fresh pore wateris present, thaw strain may not be reduced.In summary, the special characteristics ofoffehore permafrost can be detrimental in some respectsand beneficial in others. Therefore, the FIGURE 1 Thaw associated with placement of a warmproperties of subsea permafrost need to be under- pipeline in the thawed layer above ice-bonded substoodwhen predictions are being made of thaw rad- sea permafrost.90

91'CI.- ?!aUB1918 -17 -16 -15 -14 -13"12 -1110---9-8;Blcm Piue DiameterI I I I10 20 30 40 50 60 YO 80 90Allowable Pipe Temperature (OC)FIGURE 2 Influence of allowable pipe temperature on the required naturaldepth to top of ice-bonded permafrost for different salt transferrates (from Heuer et al., 1983).v 14; I1 4t .ISalt Transfer3 / I , 7OO 10Slow Salt TransferBlcm Pipe Diameter3.0m Cover Depth/2t / 9.lm Ice-Bonded Permafrost Depth -I I I I I20 30 40 50 60 70 80 90Allowable Pipe Temperature (OC)FIGURE 3 Example of the influence of allowable pipe temperature onrequired insulation thickness for different salt transfer rates, inan area of given depth to the top of ice-bonded permafrost (fromHeuer et al., 1983).------temperature will be depressed to the freezingpoint of sea water.These two cases will result in differentrates and extents of permafrost thaw under thepipeline (Heuer et al., 1983). Figures 2 and 3demonstrate the importance of salt migration inpermafrost thaw predictions for offshore pipelines.Figure 2 shows the allowable pipe temperature,assuming certain soil properties and pipedeformation criteria, as a function of depth tothe top of the permafrost before pipeline startup.The two curves were obtained by assuming "slow"salt transfer in one case and "fast" salt transferin the other. In the calculations, this differenceis expressed simply by the temperature specifiedat the mlt front: O°C and -1.9'C (correspondingto 35 0100 salinity), respectively.Except for this difference, the calculations arecarried out in exactly the same way for both cases,Le. simulating only heat transfer by conduction.This simplification is permissible for thelimiting case of either very rapid or very slowsalt migration. Intermediate cases are more difficultto calculate, since both heat and masstransfer have to be simulated numerically.For example, consider a case where the pipelineis at 5OoC and salt transfer is slow relativeto melting of permafrost below the pipe. "he calculationsindicate that the pipeline will not beover-stressed if the top of permafrost is initially14 m or more below the sea floor. If, on theother hand, salt transfer is sufficiently fast tokeep up with permafrost degradation below thepipeline, the required initial permafrost depth is

shown to be about 18 m below the sea floor.In situations where permafrost is shallowrthan the required depth indicated by this diagram,the pipeline may have to be insulated or the pipetemperature may have to be controlled in order tolimit permafrost thaw.Figure 3 shows the results of calculationsfor shallow permafrost (9 m belcw the sea floor)for a situation where an insulated line may haveto be used. The thickness of insulation required,and the allowable pipeline temperature, dependagain on the assumed rate of salt transfer. Forexample, with 10 cm of insulation, the allowablepipe temperature is shown to be 60'C in the caseof slow salt transfer, but only 20°C for fast salttransfer.It could be argued that the sediments must beof the type that only allows relatively slow salttransfer in those situations where the top of icebondedpermafrost is found close to the sea floor.Therefore, the more optimistic right-hand curve onthis diagram may be applicable for most situations.This point deserves further investigation.In conclusion, it appears that mechanism ofsalt transport in sea floor sediments can play asignificant role in the thermal design of offshorepipelines. However, I must also emphasize that,

GEOTECHNICAL AND ENGINEERING SIGNIFICANCEOF SUBSEA PERMAFROSTD.W.HayleyEBA Engineering Consultants, Ltd.Edmonton, CanadaMy role on the panel Is to buffer the stateof-the-artscience being discussed with more pragmaticengineering considerations. I plan to dothis by reviewing some of the implications of subseapermafrost in the exploration and productionof offshore resources. This wlll be based on exposureto current standards of practice in boththe Canadian and Alaskan sectors of the BeaufortSea. I wlll discuss several concerns that havehad little or no coverage at the Fourth InternationalConference on Permafrost, and I also wishto suggest how we can improve our approach to siteinvestigation and data assimilation. Finally, insteadof discussing hcw well we can deal with certainproblems, I will highlight some deficienciesin our approach to offshore engineering when permafrostis present.First, let us look at the SOH10 Arctic NobileStructure (SAMs) that has been proposed €or use inHarrison Bay, Alaska (Fig. 1). This self-containedstructure would be floated Into place andballasted onto the seabed, and then large piles,or spuds, would be driven into the bed. The spudswill not carry a vertical load but are required todevelop sliding resistance under an applied iceload. This innovative design evolved from a desirefor a universal structure applicable €or mostseabed soils in Harrison Bay.The soil profile shown in Figure 2 is fromone of the more rroublesome sites in Harrison Bay.Stiff, overconsolidated clay or silt is present atthe seabed, and ice-bonded permafrost is presentat a depth of about 10 m. "he shear strength ofthe clay decreases with depth, and a distinct zoneoE soft clay with a shear strength of only about25 kPa is present just above the ice-bonded perma-SHEAR STRENGTH (Wa)0 251000FIGURE 2 Shear strength of unfrozen soils, SiteA, Harrison Bay, from Bea et al. (1983).FIGURE 1 Mobile exploration structure (SAMs),from Gerwick et al. (1983). FIGURE 3 Stability evaluation.93

94frost. The significance of this soft zone in relationto the SAMs is shown in Figure 3. An overallstability evaluation for this structure suggeststhat the critical failure plane could extenddown to the soft zone, with the obvious implicationthat much of the sliding resistance is pickedup by the portion of the spuds embedded in thebonded permfrost. Fundamental soil parametersrequired for analysis of this structure includethe shear strength of the ice-bonded permfrost aswell as its modulus and creep characteristics.The question of pile driveability or resistanceto penetration also surfaces for a structureof this type and has nor been adequately addressed.We have had some success with fieldmethods for evaluating the bearing capacity ofsubsea permafrost by static cone penetration tests(CPT) using procedures similar to those describedby Ladanyi (1976). But although the engineeringproperties of permafrost can be measured in thelaboratory, acquiring, handling, and testing offrozen saline soil can be a problem. The propertiesof these materials are very sensitive to variationsin temperature, movement, and drainage ofsaline pore water and deformation that may occurduring sampling and handling. Therefore, there isa place for techniques that can be used to measurematerial properties in sifu, such as the use ofthe pressuremeter discussed by Briaud et al.(1983).I would like to address briefly the implicationsof thawing subsea permafrost as it affectsproduction structures. Offshore production willrequire mltiple wells in close proximity to eachother (Fig. 4). In some cases, wel deviations orslant hole drilling within the permafrost may berequired to develop shallow reservoirs. Deviatedwells will be subjected to complex casing loading;to my knowledge this problem has not been assessed.Soil movements at depth, furthermore,will be reflected by surface settlements. In somecases, it may be possible to locate foundationsfor production wells outside the zone of influence.However, this is probably not feasible fordeep-water structures, and therefore foundationdesign will have to take surface subsidence intoTABLE 1 Observed permafrost features unique tooffshore locations1. Freshwater ice in nonbonded saline silt orclay (crystals and segregated lenses)2. Alternating bonded sand and nonbonded silt orclay (identical temperatures)3. Excess ice in sand above a contact with underlyingnonbonded clay4. Hypersaline conditions belw bonded intervalsin sands and clays (salt exclusion by freezing?)5. Significant differences in degree of bondingwith subtle textural change (silt/clay)TABLE 2 Improvements needed in arctic offshoreSite invesrigation practice.1. Look beyond immediate requirements when planningprograms.2. Improve wireline coring techniques in permafrost.3. Log geologic details.4. Adopt on-site testing of frozen soils- Time-domain reflectometry for unfrozen watercontent- Refractometer for salinity content measurements5. Expand in situ testing methodology- Cone penetration testing in permafrost- Pressuremeter testing in permafrostPRODUCTIONFIGURE 4Some concerns arising from thaw around production wellbores.

95conaideration. The use of pad foundations withprovision for re-leveling is not new for norrhernstructures, although application of such drasticprocedures in design of large production modulesis not readily accepted. A prerequisite to rationaldesign will be a proven capability to predictsettlement magnitude and dietribtion, togetherwith 8 knowledge of how the settlementsmight develop during the life of the structure.A key element that has been missing in mostanalyses conducted to date has been a geotechnicalknowledge of soil properties throughout the permafrostzone. Technology currently exists to obtaincontinuous cores to the bottom of permafrost andto characterize fully the engineering propertiesof this material through laboratory testing. However,surprisingly little has been reported in theliterature on the properties of deep subsea permafrost.Clearly, subsea permafroar presents a new setof engineering challenges. The requirements forcareful determination of site conditions cannot beoverstressed. Some of our observations resultingfrom the past decade of data collection in theBeaufort Sea are shown in Table 1. Routine siteinvestigation practice is not adequate to dealwith these conditions and to provide parameters ofthe type needed for design. Some of the improvementsthat we need to see in site investigationpractice are listed in Table 2, in hope of stimulatingapplied research directed toward their understanding.ReFERENCESBea, R.G., Nour-Omid, S., and Coull, T.B., 1983,Design for dynamic loadings, Paper presentedat Conference on Geotechnical Practice inOffshore Engineering, Austin, Texas.Briaud, J.L., Smith, T.D., and Meyer, B.J., 1983,Using the pressuremeter curve to designlaterally loaded piles: 15th Offshore TechnologyConference, Paper OTC 4501, Houston,Texas.Gerwick, B.C., Potter, R.E., Matlock, H., Mast,R., and Bea, R.G., 1983, Application of multiplespuds (dowels) to development of slidingresistance for gravity-base platforms:15th Offshore Technology Conference, PaperOTC 4553, Houston, Texas.Ladanyi, B., 1976. Use of the static penetrationtest in frozen soils: Canadian GeotechnicalJournal, V. 13, no. 2, p. 95-110.

Pipelines in Northern RegionsPANEL MEMBERSOscar J. Ferrians, Jr. (Chairman)", U.S. Geological Survey, Menlo Park, California, USAAmos C. Mathews, Office of the Federal Inspector,Alaska, USAAlaska Natural Gas Transportation System, Anchorage,Hans 0. Jahns, Exxon Production Research Co., Houston, Texas, USAMichael C. Metz, GeoTec Services fnc., Golden, Colorado, USAElden R. Johnson, Alyeska Pipeline Service Co., Anchorage, Alaska, USA0.J.INTRODUCTIONFerrians, Jr.Because of the critical need to develop newsources of oil and gas, several major pipelinesand related facilities have been constructed inthe arctic and subarctic regions of the world duringthe last two decades, and undoubtedly morewill be constructed in the future. These regionspose special engineering problem and are environmntally"sensitive. " Consequently, they requirecareful consideration to ensure the integrity ofpipelines and related facilities and to minimizeadverse environmental impacts. One of the mostimportant factors to be considered is permafrost.Permafrost is a widespread natural phenomenonin northern regions, and it underlies approximately20% of the land area of the world. The permafrostregion of Alaska includes 85% of the state(Ferrians et al., 1969), the permafrost regions ofCanada and the U.S.S.R. cover about 50% of eachcountry, and the permafrost region of China covers*The panel chairman wishes to acknowledge theassistance of Fred Crory, Cold Regions Researchand Engineering Laboratory. in organizing thepanel. Unfortunately, Mr. Crory was unable toattend the conference.about 20% of that country (see Frontispiece).Zhe most serious permafrost-related engineeringproblems generally ate caused by the thawingof ice-rich permafrost, which results in a loss ofbearing strength and a change in volume of icerichsoil. Under extreme conditions that permitvery rapid thawing, ice-rich, fine-grained soilcan liquefy and lose essentially all of itsstrength. A more common occurrence is differentialsettlement of the ground surface.Proposals to chill the natural gas in buriedpipelines as a means of mitigating the problemscaused by the thawing of permafrost pose a differentproblenr-namely frost heaving, due to thefreezing of pore water in eoils surrounding thepipe and to the freezing of additional water attractedto the freezing front.There are numerous topics that could havebeen treated in a discussion of pipelines innorthern regions; however, for this report thefollowing important and timely subjects have beenselected:Pipelines in the northern U.S.S.R.Hot oil and chilled gas pipeline interactionwith permafrostPipeline therm1 considerationsPipeline workpads in Alaska- Performance of the trans-Alaska oil pipeline97

99pads, bedding and padding of the pipe, riprap, andconcrete aggregate, construction is difficult andexpens ive.Perennially frozen ground, or permafrost, iswidespread in the northernmost coastal lowlands,tundra, and forest tundra zones of western Siberia.In these areas, the thickness of the permfrostranges from 500 m in the north to 50 m inthe south. Permafrost is discontinuous south ofthe Arctic Circle, and it occurs only in peat bogssouth of the 63rd parallel. The temperature ofthe permafrost in these more southerly areas generallyranges from O°C to -1'C or -2OC and, consequently,it is very sensitive to disturbances. Ifthe thermal regime at the ground surface is altered.thawing quickly takes place.Pipeline construction in permafrost regionscan cause thawing of permafrost, thaw settlement,and thermal erosion. These detrimental effectsgenerally result from removal of the vegetationcover, placelaent of backfills or thin workpads,modification of surface and subsurface drainage,or changing the albedo due to the accumulation ofdust. During construction, many of these mninducedchanges can be severe; but they can becontrolled by proper design, scheduling, and timelymaintenance, including revegetation compatiblewith the new environment. It is necessary to beable to predict the potential environmental changes,since they can directly influence the successfuloperation of a pipeline system. "he measurestaken to protect the environment are equally applicableto safeguarding the integrity and reliabilityof the pipeline system. Therefore, thebest engineering solutions and the best measuresto protect the environment and the pipeline areclosely interrelated and interdependent. Obviwsly,the thermal effects of warm oil or gas or ofchilled gas mst be considered in order to design,construct, and maintain pipelines properly innorthern regions.The first major pipeline constructed in theFar North was the 529aun-diameter, 600-km-long naturalgas pipeline serving Yakutsk (Pig. 1). Thispipeline, which includes 250 km of abovegroundline, has been operating successfully for morethan 15 years. A system of gas pipelines servingthe city of Norilsk was constructed entirely aboveground except for river crossings. One line ismore than 600 km long and 720 mm in diameter, anotheris 300 Irm long but has a smaller diamter.Construction of these pipelines started in 1968,and the first line was completed in 1969. Theseearly gas pipelines in permafrost areas were builtlargely above ground to eliminate the possibilityof adverse impacts on permafrost. As more experienceis gained in pipeline construction in northernareas, underground placement has gained favor.Large transcontinental gas pipeline systemswere constructed in the 1970s. These pipelinesha e a diawter of 1420 mm and pressure of 75 kg/cms . The first giant pipeline, with a length of3000 km, originated in the northern part of theTyumen region near the Medvezhye gas field. During1981-1985, a multiline system of five parallelpipelines will be constructed, each with a diameterof 1420 mm. Three of these lines, the Urengoy-Gryazovec-Moscow,Urengoy-Petrovsk, and Urengoy-Novopskov,have already been constructed.During this period, the Urengoy-Pomary-Uzhgorodgas pipeline for exporting gas also will be putinto operation. The length of this pipeline is4500 km. Oil pipelines from the northern regionsalso are under construction. One of the largestoil pipeline system is the main pipeline Ust-Balyk-Kurgan-Ufa-Almetyevsk, having a diameter of1220 mm and a length of more than 1800 km.The construction of pipelines is most advantageouslydone in wfnter, when damage to theground surface can be held to a minimum and thefrozen ground ensures that heavy equipment canwve about easily on the tundra and in swampyareas. Underwater crossings are built in the winterusing the ice cover as a platform. To reducethe impact of gas pipelines on permafrost, a methodof cooling the gas to a temperature of -2 to-3-C has been developed, and cooling facilitiesare currently being constructed at the Urengoy gasfields.

HOT-OIL AND CHILLED-GAS PIPELINE INTERACTION WITH PERMAFROSTA.C.MathewsOffice of the Federal Inspector, Alaska Natural Gas Transportation SystemAnchorage, Alaska, USAThe complications arising from the interactionof pipelines and permafrost generally can becategorized as: (1) surface deterioration, (2)erosion, (3) drainage interruption, (4) thaw settlement,(5) frost heave, and (6) effects associateddirectly with the construction effort. Indealing with these complications, there is noclear-cut distinction between cause and effect--drainage interruption can cause aufeis. which cancause surface deterioration, which causes drainageinterruption, etc. It is this circular, exacerbatingchain of events that can cause such chaosif permfrost problem are not anticipated and designedfor, or If mitigative ueasures are not takenimmediately when a problem is identified. Thawsettlement occurs to a structure when heat is introducedcausing ice-rich soils under its foundationto thaw. Frost heave is a complementaryproblem that occurs when subfreezing cold is introducedinto non-frozen, frost-susceptible soil.Moisture, attracted to the cold, percolatesthrough the soil and freezes at the cold front inquantities excess to the pore capacity of thesoil. Over a period of time, a large frost bulbcan build up, causing heaving in a structure aboveit. Finally, there are a number of complicationsarising directly from construction, such as excavation,the dormant period (when the pipe is completedand buried but not yet carrying product),the gravel work pads used in summr, snowjice padsused in winter, and the massive requirenvents forgravel to ameliorate permafrost complications.For reasons of both security and economy,pipelines generally are best kept below ground.Therefore, the trans-Alaska oil pipeline was buriedwherever possible, in unfrozen soil and inthaw-stable permafrost. In areas of thaw-unstablesoils, refrigerated piles were used to elevate theline and to preclude settlement of the piles dueto permafrost thawing. At those few locationswhere it was necessary to bury the line in thawstablesoil, the trench was refrigerated and/orthe line was heavily insulated to provide stability.Refrigerated piles were used to elevate theline in high temperature permafrost to precludethaw settlement of the piles due to permafrostthawing caused by the construction disturbance.Finally, all piles had to be designed against annualfrost jacking. Designers of the proposedAlaska Highway natural gas pipeline plan to burythe line everywhere, with the exception of a fewstream crossings. Because the gas is chilled,this should work wel in permafrost areas, providedthat thawing problems do not arise during thedormant period prior to startup. But in thawedfrost-susceptible soils, the designers face afrost-heave problem whose magnitude is just nowbeginning to be fully understood. They plan tosolve this problem by identifying the areas thatcontain these frost-susceptible soils and then employingsuitable mitigative measures in construction.Underground stream crossings are apt to bea problem because the cold pipe could cause slowmovinggroundwater to freeze and, in turn, affectsurface drainage; faster flow rates seem to dissipatethe effects of cold pipes. In any event, thepipe could be insulated to reduce the cold sink toa level that will not cause significant frostgrowth or, as a last resort, the pipe could be elevatedover small streams where the effects are inquestion.

PIPELINE THERMAL CONSIDERATIONSH.O.JahnsExxon Production Research CompanyHouston, Texas, USAThe thermal aspects of pipelines in permafrostterrain are of paramount importance. Infact, it is difficult to talk about arctic pipelineswithout mentioning thermal interactions withthe surrounding soil or, specifically, the consequencesof a phase change in the soil's moisturecontent. In essence, this is what makes arcticpipelines different from conventional pipelines.Figure 1 shows four schematic cross sectionsof a buried pipeline with different thermal regims.A warm pipeline in permafrost is shown inFigure la, a warm pipeline in thawed soil in Figurelb, a cold pipeline in permafrost in FigureIC, and a cold pipeline in thawed soil in FigureId. It also illustrates the two basic mechanismsthat give rise to engineering concerns: thaw settlement(Fig. la) and frost heave (Fig. Id). Thewarm pipe In permafrost will cause a thaw bulb togrow around it. If the soil is ice-rich therewould be subsidence, as indicated by the sag inthe soil layers in Figure la. If the resultingsettlement over-stresses the pipe, mitigative measureswill be called for. Figure Id, a mirror imageof Figure la, shows a freeze bulb growingaround the cold pipe in thawed soil. If the soil.is frost-susceptible, it may heave, deforming thepipe. If the heaving is sufficient to overstressthe pipe, mitigative measures would be needed.The two remaining cases (Figs. lb and IC) are trivial--notmuch happens with a cold pipe in frozenground or with a warm pipe in thawed soil, exceptfor some thinning of the active layer above thepipe. However, there are some complications atpermafrost boundaries.WARMPIPECOLDPIPEa. b.C. d.For both the thaw settlement (Fig. la) andfrost heave (Fig. Id) cases, the allowable thaw orfreeze bulb size depends on the mechanical interactionbetween the pipeline and the soil. Two designapproaches are possible. First, the designcould be based primarily on thermal considerations,and pipe deformation would be avoided byminimizing the size of the thaw or freeze bulb.Alternatively, pipe deformation could be allowedup to some operational limit. This second approachwould have a less stringent thermal design,but more would have to be known about the mechanicalbehavior of pipes and soils.The first method of thermal control thatcomes to mind is to insulate the pipeline. Theeffect can be dramatic. In fact, with good lnsulation,such as 10 to 15 cm of "jacketed" urethane,it is possible in many cases to prevent the formationof a thaw or freeze bulb, or to limit itssize to only a few decimeters below the pipe, asshown in Figure 2. Design of the insulation systemmust consider the long-term effects of moistureabsorption. If necessary, the natural soilbeloru the pipe could be excavated half a meter orso and replaced with select material such as gravelthat would undergo little thaw strain or frostheave. The term "overexcavation" is used for thisconstruction mode.There is a serious problem, however, with theconstruction mode shown in Figure 2a. This thawbulb will grow slightly in size during the summerand will link up with the active layer above thepipeline. During the winter, the active layerfreezes and: the thaw bulb becomes isolated. Asfreezing continues, the pipe may be subjected tofrost jacking due to pore water expansion, independentof whether or not the soil in the thawbulb is frost-susceptible. This may be an unacceptablerisk.The buried insulated pipeline mode has anotherlimitation: when the soil temperature is nearthe freezing point, insulation alone is not sufficientto stop the growth of a thaw or freeze bulb;a. b.FIGURE 1 Schematic cross sections of a buriedpipeline with different thermal regimes: (a) warmpipeline in permafrost, (b) warm pipeline in FIGURE 2 Schematic cross sections showing thethawed soil, (c) cold pipeline in permafrost, and effects of insulation on (a) a warm pipe in cold(d) cold pipeline in thawed soil. Thaw subsidence permafrost and (b) a cold pipe In warm thawedis shown in (a) and frost in heave (d). soil.101

102a. b./6RAVEL PAD,611AVEL PAD EXTEHDEDa'nQnb.FIGURE 3 Schearatic cross sections showing theeffects of surface disturbance (gravel pad) on (a)a warm pipe buried in warm pennafrost and (b) acold pipe buried in cold thawed soil. Both pipesare insulated.FIGURE 4 Schematic cross sections showing thethermal effects of an elevated pipeline and agravel workpad on (a) cold permafrost and (b)permafrost.warmit will only slow it down. But during the 20- to30-year lifetime of the pipeline, it will growdeeper than any practical amount of overexcavation.That is why Figure 2a is labeled "coldpermafrost" and Figure 2b is labeled ".warm thawedsoil." As a rule of thumb, we may assume thatthese diagram refer to permafrost at temperaturescolder than -6'C and thawed soil warmer than t3OC.'Ihe intervening temperature regiE from -6 to +3'Cis the one that is most difficult to design for,for two reasons: (1) the fact that pipeline insulationis not sufficient to prevent long-termgrowth of a freeze bulb or a thaw bulb, as alreadydiscussed, and (2) the construction surface disturbanceand its effect on the thermal regime inthe soil.The surface disturbance causes warming bothIn permafrost and in thawed soil. Therefore, thetwo cases shown in Figure 3 are no longer symmetrical.In warm permafrost (Fig. 3a), the gravelpad used for construction and pipeline maintenancecauses long-term permafrost degradation, perhaps 6to 9 m deep during the life of the pipeline. Ifthe soil is ice-rich, this pipeline mode may notbe acceptable. In the case of the trans-Alaskaoil pipeline, the answer was to elevate.The surface effect is very different for thecold pipeline in thawed soil (Fig. 3b). In fact,the surface disturbance is beneficial in that ittends to counteract the effect of the cold pipeline(Jahns et al., 1983). 'Ihe disturbance can beenhanced by extending the gravel pad on both sidesof the pipeline trench. Calculations indicatethat this pipeline mode should be applicable inessentially all situations where the soil is alreadythawed and is covered with natural vegetation.In contrast to standard practice, this designdoes not call for revegetation. On the contrary,uY3asurea may have to be taken to limit revegetation.The elevated pipeline mode shown in Figure 4works equally well for both cold and warm pipelines.However, a distinction needs to be madebetween cold permafrost, which remains stable inspite of the surface disturbance, and warm permafrost,which degrades under the gravel pad. Designingan elevated pipeline for cold permafrostis straightforward, as shown in Figure ha. Althoughthe active layer depth increases, the pilesupports are frozen in and remain in frozen soilCROSS SECTIONSIDE VIEWFIGURE 5 Schematic cross section and side view ofan elevated pipeline with heat pipes (mitigativepipeline mode) on warm permafrost.during the life of the pipeline. In warm perma-Erost, shown in Figure 4b, the situation is different:The permafrost degrades under the gravelpad and may subside and cause downdrag forces onthe pipeline supports. The piles have to be designedto withstand these forces in addition tothe weight of the pipeline. This may require verylong piles and high installation coat. In somecases, the required pile lengths may become impractical.The thermal VSM design for the trans-Alaska oil pipeline was developed as a solution tothis problem. A pair of heat pipes inside eachpile removes heat from the surrounding soil duringthe winter to prevent thawing in the vicinity ofthe piles, out to a distance of about 3 m. Figure5 shows the configuration as it may look 20-30years after the installation: the pile supportsare surrounded by pillars of frozen soil, whilethe soil under the gravel pad and between supportshas thawed to depths of 6 to 9 m.Under certain conditions, heat pipes may alsobe useful €or a buried, cold gas pipeline. Thismy arise at transitions where the pipeline passesfrom frozen, thaw-unstable ground into thawed,frost-susceptible soil. Many such boundaries existin nature and they are not always clearly defined.Therefore, insulated pipe may have to beextended some distance into frozen ground. Figure6 shows two situations that may arise. Figure 6ashows the insulated cold pipeline where it hasbeen extended into the frozen ground near the permafrostboundary. Since the cold pipe is insulated,it is not effective in preventing permafrostdegradation under the gravel pad. The long-termresult is similar to that for insulated, warm pipeshown in Figure 3a. Perhaps only a small frozenzone will remain below the pipe, not sufficient to

103a. b. time. Later on, once the near-surface perlayer has thawed, the newly formed freeze bulb andand relic permafrost below the pipeline would beginto degrade. Thus, the pipeline could undergo"""-LOWlERM THlW-first heaving and then subsidence. To overcomethese problems, the pipeline rmst be designed tobe insensitive to the particular geometry of permafrostboundaries..Figure 7 shows an example of a mitigativemode for permafrost boundaries based on the use offree-standing heat pipes placed in a row on eitherFIGURE 6 Schematic cross sections showing theside of the buried cold pipeline. The function ofthermal effects of an insulated, cold, buriedthe heat pipes is to freeze any thawed ground inpipeline at permafrost boundaries (a> in warm per- the vicinity of the pipeline and to keep initiallymafrost and (b) in mixed frozedthawed soil.frozen ground frozen. The main direction of heatHEAT- PIPEflow is horizontal, radially into the heat pipes,RAOllTORso the potential for frost heave is greatly reduced.This conclusion is supported by experiencefrom the trans-Alaska oil pipeline where heavingof thermal VSM's (vertical support members) hasnot been a significant problem; however, some minorheave has occurred (Table 1). Depending on thetiming of heat pipe installation and pipelinestartup, it may be possible to eliminate pipelineinsulation in this construction mode. Longitudinalspacing of the heat pipes, shown in the sideview (Fig. 7a), would be rmch closer than in thedesign for the trans-Alaska oil pipeline, perhapsevery 3 m or so, since a continuous freeze bulb isa.b.desired under the pipeline. The total number ofheat pipes should not be excessivthis special pipeline mode would be required onlyFIGURE 7 Schematic cross section and side viewsporadically for short distances--perhaps 30 m--onshowing the thermal effects of an insulated, cold, either side of a permafrost boundary.buried pipeline with heat pipes (mitigative pipe-Transition problems also occur for warm pipelinemode) at permafrost boundary at (a) time of lines. These problems were avoided on the transinstallationand (b) long-term.Alaskan oil pipeline by going from the buried tothe elevated mode before entering frozen, thaw-unstablesoil. The elevated mode was also used inCOLD PERMAFROST WARY PERMAFROST THAWED Sol1areas of mixed frozen and thawed soil.Figure 8 shows a summary of the pipeline constructionmodes that have been described: threefor the warm pipe (Figs. Ea, 8b, and 8c), andWARMthree for the cold pipe (Figs. Bd, 8e, and 8f).PIPEThe modes shown for the warm pipeline are the onesused for the trans-Alaska oil pipeline: simplePERMAFROST PIMAFROST BOUNDARY THAWED SOILelevation on cold permafrost, elevation with heatpipes in warm permafrost, and conventional burialin thawed soil. The three buried modes for a coldpipeline are conventional burial in permafrost,heat pipes at permafrost boundaries, and insulatedpipe in thawed soils. An extended gravel pad,shown in Figure Sf, Is used to take full advantageof the surface disturbance for preventing theFIGURE 8 Schematic cross sections showing exampgrowthof a freeze bulb. For the same reason, relesof mitigative pipeline modes for both warm andvegetation would be limited. These measurescold pipelines under various soil conditions.would, of course, not be required in areas wherethe thawed soil is not frost-susceptible, or wheregive reliable support. Accurate predictions ofit can be shown that the expected amount of frostheave would not over-stress the pipe.thaw bulb geometry and pipe deformation are diffi-Some of the more important design consideracultto make in this case. Groundwater flow could tions for warm offshore pipelines in areas of iceleadto additional thaw. A more complex situation bonded subsea permafrost are shown in Figure 9.with alternating layers of frozen and thawed soilSubsea permafrost is warm permafrost, not muchis shown in Figure 6b, In this case, the uppercolder than the overlying seawater, typlcallyfrozen layer would shield the soil below the pipe- about -1 to -3'C. In that regard, it Is similarline from the effect of the surface disturbanceto the warm permafrost in central Alaska, but theduring the early years of pipeline operation. A similarity ends there; there is no active layertemporary freeze bulb could be formed during this and no organic layer, and therefore construction

104TABLE 1 Perform an ce of the var 3ous pi le types used to elevate theTrans-Alaska Oil Pipeline.No. 4 settled % jackedPile type Soil conditions installed (> 9 cm) (> 9 cm)Thermal Warm permafrost 42,720 0.5 1.2Thermal Thawed ground 18,420 0.6 3.4Adf reeze Cold permafrost 13,473 0.3 0.0Frictionlendbearing Thawed ground 1,992 2.1 0.3Other Mixed profiles 1 , 127 0.2 1 .oICEDOUPETotal"-77,732 0.6 1.9fact that the rate and effect of salt migrationSTRUDELare difficult to model. Therefore, in sow calcu-SCOURlations (Heuer et al., 1983) two extremes havebeen evaluated: one in which salt migration isnegligible in the time frame of the operating lifeSALINE0HEAT AN0 SALT TRANSFERPORE WATERFIGURE 9 Schematic cross section showing criticalelements of a buried pipeline underlain by offshorepermafrost.causes no thermal disturbance. A very drasticsurface disturbance took place at the time of inundationby the sea, raising the surface temperatureto near the freezing point and initiating agradual process of downward salt migration as seawaterreplaced the original pore water in the sediment.Since the mean annual sea floor temperatureis below O'C, it is the interplay between thewarming process and the salt migration that determinesthe rate at which the offshore permafrostdegrades. Depending on the type of sedilaent andon the ;time since inundation, the top of the permafrostis found at greatly varying depths beneaththe sea floor.Other factors that are important for offshorepipelines are Ice gouges and strudel scour. depressionsthat could uncover the pipe and perhaps damageit. Thus, offshore pipelines in shallou arcticwaters may require relatively deep burial upto 3 m or more. This brings the pipe closer tothe permafrost table and tends to aggravate potentialthaw-settlement problems.Generally, offshore pipelines would be muchsmaller in diameter than large trunklines onshore,typically only 30 to 60 cm. Therefore, such lineswould be more tolerant to thaw settlement, and acertain amount of permafrost thaw below the plpelinewould be acceptable. On the other hand, predictionsof permafrost thaw are complicated by theof a pipeline, and one in which salt migration issufficiently rapid to maintain a concentrationsimilar to that of seawater at the advancing edgeof the thaw bulb. In the computer simulation, theassumed melting temperature of the permafrost isnear O°C for elat salt migration and -1.9'C forfast salt migration.Conventional burial of uninsulated pipe in atrench is probably acceptable when the top of theice-bonded permafrost is more than 27 m below theseafloor. Calculations show that the warm pipemay still cause permafrost melting at this depth,particularly in sediments where salt migration iseffective. However, any differential settlementat these depths would be masked by the substantialthickness of overlying thawed sediments. 'Iherefore,the effect on the pipeline would be greatlyreduced. Pipeline insulation may be required ifthe permafrost table is less than 27 m below theseafloor. This value depends, of course, on specificdesign values for thaw strain, pipe size,and temperature. Again, some thawing of permafrostwould be allowed, lmt the allowable thaw Isreduced in this case because there would be lessdampening of differential settlement.Two potential mitigative modes for offshorepipelines are shown in Figure 10. If ice-richFIGURE 10 Schematic cross sections of ttm possiblemitigative pipeline modes for offshore permafrostareas, (a) by overexcavating and backfillingwith thawed material and (b) by using a causeway.

105permafrost occurs near the seafloor, a certainportion of it could be removed from below thepipeline by overexcavation and backfilled withthawed soil before the pipe is laid into thetrench. The required trench depth could be substantial,perhaps as much as 9 to 12 m in someareas where deep pipeline burial is required forprotection against ice gouging (Fig. loa). Thiskind of excavation would be costly, but it is feasiblewith modern dredging equipment. Laying thepipeline above water in a causeway is an alteraativefor shallav water. With the causeway surfaceexposed to the cold air, It will gradually developa frozen core. Rather than thawing the subseapermafrost, this construction mode may actuallylead to the formation of new permafrost below theoriginal seafloor (Fig. lob).Feasible and practical pipeline modes havebeen identified for the three nrajor types of pipelinesthat are needed for petroleum development inAlaska's permafrost areas: hot oil pipelines andcold gas pipelines onshore, and warm burled underwaterpipelines offshore. Much work is requiredto develop the most cost-effective configurationand construction method for each particular pipeline.However, the technology is available now todesign, construct, and operate onshore and offshorepipelines for developing Alaska's petroleumresources in a safe and environmentally acceptablemanner.

PIPELINE WORKPADS IN ALASKAM.C.MeteGeoTec Services Inc.Golden, Colorado, USAThe construction of oil and gas pipelines inremote northern regions generally requires thepreparation of a working surface or workpad thatwill support construction traffic and provide accessduring the operation of the pipeline. Cmmonly,gravel fill is used for this purpose. Agravel workpad, however, usually causes significantthermal disruption and permafrost degradation,which makes the effects of the workpad aprimary consideration in oil and gas pipeline design.In most instances the long-term thermal effectsof the workpad are an integral part of thelong-term design and performance expectations of apipeline system.Early coordination with construction and operationspersonnel is required to establish theshort- and long-term performance criteria for anyworkpad. Normally there is no need to design aworkpad capable of supporting heavy wheel-loadtraffic for the design life of a pipeline (25-30yr). Significant cost savings can be realized ifthe workpad is designed to support heavy constructiontraffic only during the construction phase ofa pipeline (2-3 yr) and, with periodic maintenance,to provide limited access for light surveillanceand maintenance traffic during project operations.The Trans-Alaska Pipeline System (TAPS),which connects the oil fields at Prudhoe Bay tothe ice-free port of Valdez, had a constructionworkpad for its entire 800-mile length. Most ofthe TAPS workpad was designed and constructed aseither an all-granular embankment or a polystyrene-insulatedembankment. Two short segments ofthe pipeline were constructed utilizing sncw workpads.The design Intent of the TAPS workpad wasto provide only the thickness of gravel, and insome cases polystyrene insulation and gravel, thatwould allow short-term passage of heavy constructionequipment.Generally an overlay workpad was utilized forthe trans-Alaska hot oil pipeline, although therewere soue areas where cut and fill was used. Formost of the permafrost areas the basic overlay embankmentshown in Figure 1 was used. A structuralembankment was conetructed over both thawed groundand permafrost. In permafrost areas this embankmentallows for the development of an increasedactive layer and allows for long-term deep thawbeneath the workpad. The structural embankmentwas for both the aboveground and belowground pipelinein warm permafrost areas and for the belowgroundpipeline in cold permafrost areas. For theaboveground pipeline segmente of the trans-Alaskapipeline in cold permafrost areas, two types ofthermal workpads were considered. An all-grave1thermal embankment design of sufficient thicknessto prevent thaw beneath the embankment base wasC. d."&"1I-Thermal-FIGURE 1 Examples of basic overlay embankments.Structural embankment (a) over thawed ground and(b) over permafrost, and thermal embankment (c)without insulation and (d) with insulation.considered first. For TAPS, however, an alternativethermal workpad design, which utilized a syntheticinsulation layer at the base of a thingravel overlay, was developed as an effective alternative.The synthetic insulation material selectedfor this design was extruded polystyrenefoam manufactured by the Dm Chemical Company.Consequently, gravel requirements were greatly reduced.The design of the synthetic insulation wasbased on maintaining a frozen subgrade for a constructionperiod of approximately 2-3 years and onlong-term thaw not exceeding one and a half timesthe original active layer depth. Performance mnitoring,after 5 years, indicates that the insulaKedworkpad is still maintaining frozen grounddirectly beneath the insulation.The use of a polystyrene-insulated workpad onTAPS resulted in significant cost savings througha reduced requireinent for gravel embankment materialsand reduction in the embedment length of thevertical support members (VSMa). The reduction ingravel use also reduced terrain disturbance andenvironnental damage associated with the developmentof borrow sources. Except for areas of localizeddistress due to construction-related insulationplacement problems and to post-constructionremoval of or damage to the insulation layer,the 80 miles of insulated workpad has performed asintended.The thermal-insulated workpad was designed toprevent long-term thaw of permafrost and is an integralpart of the VSM design on the North Slopeportion of the pipeline. In contrast, the structuralworkpad was designed to support the shorttermconstruction traffic loading but to allow

107s* """""" ""IStructural WorkpadSnow/lce Workpadd, = Bask thickness componentdt :Thickness for thawing permafrost solisd, =Thickness for summer workpad constructionFIGURE 2 Components procedure for designingstructural workpads.thawing of permafrost. Deformation of the surfaceand degradation of permafrost was anticipated andyearly maintenance programs were planned to maintainthe workpad for use by light surveillance andpipeline maintenance vehicles.The structural workpad design used on TAPSutilized the component procedure shown in Figure2. This design procedure was used for workpadsconstructed In warm permafrost and for belowgroundpipeline areas in cold permfrost. 'Xhe totalthickness of the workpad D is equal to the basicthickness db plus an allowance dt for thawingpermafrost soils and an additional allowance d,for summer construction of a workpad. The dbcomponent is the basic thickness required forstructural support over a certain soil type for adesign wheel load regardless of thermal state.dt is an added thickness to account for thawingpermafrost soils and is related to the predictedthaw-strain in the upper 5 ft of soil. d, isthe thickness added to account for summer constructionover soils that are thawed in the naturalactive layer. Figure 2 is not meant to representthree different structural layers but to demonstratethe additive thickness of the three components.In thawed areas, only the db thicknesswas used. In permafrost areas, where the workpadwas constructed In the winter, the combined thicknessof db and dt was specified. For summerconstruction in these same areas, the specifiedthickness was the total of all three components.The component procedure was verified by test sectionsconstructed prior to pipeline construction.The all-gravel structural workpad was designedto support the high bearing pressures associatedwith pipeline construction wheel-loadsand to compensate for thaw strain in the underlyingsoils during construction. Loss of capacityto support heavy wheel-loads on the workpad due tothawing permafrost was expected to occur afterconstruction, but was not considered to be a problemsince operations traffic would consist oflight-wheel-load surveillance and maintenance vehiclea.As anticipated, deterioration of the permafrostin non-insulated gravel workpad areas hasresulted in thaw settlement and a weakened subgrade.Fines have been pumped into the overlaymaterial, resulting in a significant loss of trafficability,but yearly workpad maintenance allowspassage of light-wheel-load vehicles.Low-cost gravel resources are not present everywhereon the Alaskan North Slope. Gravel resourcesdiminish in both quantity and quality westBupports Ilght monltorlnolSupports conmtructlon eaulprnentmaintenance vshlclsa In summer (mostly tracked) for one winterFIGURE 3 Example of a combination structural andsnaw/ice workpad used for construction of an elevatedoil pipeline during the winter.of Prudhoe Bay, and development activities aremoving in that direction. The resulting highercost of gravel necessitates the development ofworkpad configurations that reduce the demand forgravel resources.Willingness to accept certain limitations onpipeline maintenance activities can result in additionalsavings. If there la no need to providefor year-round access during the operationalphase, the designer can consider using a seasonalworkpad constructed of snow, ice aggregate, orice.Variations of workpad design utilizing a narrowgravel workpad with an adjacent snow workpadas shown in Figure 3 have been successfully usedfor many years by the producing companies at PrudhoeBay. This combination gravel-snow workpadprovides for the needed width during constructionas well as access during the life of the pipelinefor surveillance and maintenance. This solutionrequires winter construction, but in Prudhoe Bay,for example, this does not represent a deviationfrom normal construction practice.The gravel workpad associated with the combinationworkpads is usually approximately 3 to3.5 ft thick and has a minimal working width. Itis utilized mostly during the winter for pipelineconstruction. Heaq-wheel-load, rubber-tired vehiclesare usually restricted to the gravel portion.During the late summer, thaw weakens thesubgrade, but light-wheel-load monitoring andmaintenance vehicles can still pass with no problems.The snow or ice workpad constructed adjacentto the gravel embankment provides a winter workingsurface for installation of pipe supports andpipelines. This has worked successfully at PrudhoeBay, although there is some risk to thestruction schedule during late snow years.con-Theembankment acts as a natural snow fence, however,and aids in trapping available snow by drifting.In recent years, drawing on experience andresearch conducted by the Department of Transportationin Alaska, new workpad configurations havebeen developed. The utilization of geofabrics inworkpad design is being tested In North Slope applications.Twn applications of geofabrics in workpad designare shom in Figure 4. The Atlantic RichfieldCompany has successfully employed geofabricsto encapsulate law-strength soils into embankments.Materials stripped from other operationsthat contain ice-rich silt and organic materialare encapsulated in geofabrics within the embankment.This provides for effective use of other-

108Encapsulation of low strength soils A ~ 2 Z ~ ~ ~ ~ Z ~ P ~120 l ' O LMaintain separation of materialsFIGURE 4 Two examples of the use of geofabrics inconstruction of wrkpads.wise wasted materials while reducing the requirementsfor select gravel fill. The performance ofthese embankmnts, including a portion of at leastone aircraft runway, has been good.One option that has only been tested on alimited basis, however, is the use of geofabricsto maintain separation of the workpad embankmentand underlying fine-grained permafrost soils. Inthe case of a structural workpad, the benefitsthat would be realized are the reduction of thed, design component to zero and perhaps a substantialreduction of the dt component. If onlythe ds component is considered, which accountsfor contamination of the lower portion of the embankmentby underlying fines during summr construction,a savings of 1 to 2 ft of gravel can berealized by using geofabrics.The capacity of geofabrics to maintain separationof materials is wel known. The added benefitof reinforcement over thawing permafrostsoils, which could reduce the dt design component,is not as well known. However, if the reductionof a minimal thickness of only 1 ft is considered,then gravel usage and cost differentialcan be calculated. Comparative costs of workpadconstruction based on actual North Slope projectsare given in Figure 5, with the estimated costs ofa workpad ultlizing geofabrlc shown in comparison.Since the cost of a workpad is directly related tothe haul distance from the source of gravel, thedirect cost per linear foot of workpad is plottedversus gravel haul distance. It should be emphasizedthat these are direct costs and do not includeindirect costs. As can be seen in Figure 5,we reach a break-even point between the 36-in.all-gravel pad and the 24-in. insulated grave1 padwith a haul distance of 22 miles. This simplymeans that once the haul distance for gravel isgreater than 22 miles, it becomes economicallyfeasible to build an insulated workpad. At PrudhoeBay where gravel sources are plentiful andhaul distances short, the cost of insulation isprobably not justified.However, if by using geofabrics 1 ft of graveloverlay can be saved, the break-even haul die-OO 6 10 15 20 95 30Haul Distance (miles)Direct Coats-January.lBB0. Assumsa: 30 Foot Wlde WorkpadFIGURE 5 Chart comparing direct costs of constructingvarious types of workpads.tance is only 1 mile and, therefore, a geofabricsupportedworkpad constructed more than 1 milefrom a gravel source costs less than a 36411.-thick all-gravel workpad. Maintaining separationof frost-susceptible fine-grained soils from overlyingsand and gravel with geofabrics makes problemsettlement areas easier to maintain and upgrade.This additional long-term advantage makesthis alternative well worth considering.The continued study of the performance of existingworkpads in Alaska and continued evaluationof their impacts are needed to provide design engineerswith the information required to improveworkpad design criteria. Developrnt of new andsmaller oil fields as well as other remote facilitiesin Alaska will require more cost-effectivedesigns, and one of the most critical factors willbe the availability of gravel resources. For example,gravel deposits are extremely scarce andhaul distances are greater in the very large NationalPetroleum Reserve--Alaska and other areason the North Slope than they are at Prudhoe Bay.The concept of an almost unlimited, cheap gravelresource rmst therefore by abandoned by the designer.'he higher cost of gravel in areas of futuredevelopment will require workpad designs thatuse less gravel.

PERFORMANCE OF THE TRANS-ALASUA OIL PIPELINEE. R. JohnsonAlyeska Pipeline Service CompanyAnchorage, Glaska, USAThe trans-Alaska oil pipeline is the firstlarge-diameter pipeline transporting hot crude oilacross permafrost terrain. Many technical questionsfaced designers at the time of pipeline design,hut now, after 6 years of operating experience,many of the questions regarding pipelineperformance can be answered (Johnson, 1981). Theperformance of the trans-Alaska oil pipeline hasbeen exceptionally good, with only minimal operationaland environmental problems. There havebeen some technical problems, to be sure, but theyhave been manageable and confirm the high qualityof the design.The fundamental factors differentiating thetrans-Alaska oil pipeline from most other crudeoil pipelines are those caused by an operatingtemperature of 48.6'C and the presence of permafrost.Approximately 70% of the pipeline route isunderlain by permafrost. Three basic pipeline designmodes were developed to cope with the variousfoundation conditions (Table 1). In the thawedground and in thaw-stable permafrost, the conventionalburied mode was used. In thaw-unstablepermafrost, the aboveground mode was used. Inthaw-unstable permafrost where there were accessrestrictions or where there were environmentalconstraints such as the need for extended animalcrossings, a refrigerated buried mode was used.In June 1979, two belowground pipeline failuresoccurred that resulted in leaks. These failureswere caused by 1.2 m of thaw settlement inone location and 1.7 m of thaw settlement in theother. In both cases, settlement was limited toshort 100- to 120-m-long zones underlain by previouslyundetected ice-rich permafrost.Alyeska Pipeline Service Company routinelyconducts an extensive monitoring and evaluationprogram designed to detect potential pipeline set-tlement problems. Visual surveillance detects evidenceof subsurface settlement that may be relatedto settlement of the pipeline. Where problemsare detected, monitoring rods are attached to thetop of the pipe to allow survey monitoring at thetop of the pipe for subsequent settlement. If thesettlement is severe, the monitoring rods are installedless than 10 m apart. The curvature ofthe pipe can be calculated from the survey masurementrand compared to known failure criteria.In addition to the monitoring rod program,major geotechnical and thermal investigations havebeen carried out. Since startup, over 1,000 boreholeshave been drilled to gather geotechnical informationand more than 315 thermistor cables havebeen installed to gather Information about thethermal regime of the permafrost. In addition, apipeline deformation monitoring "pig" detects evidenceof dents, buckles, and possible incipientpipeline cracking. This monitoring and surveillanceprogram has been very successf-ul in detectingseveral additional problem areas besides thetwo previously mentioned.Several techniques have been used to repairthe pipeline. In the Atigun Pass area, the settledpipeline was excavated, conventional elevated-pipelinehardware was installed to support thepipe, and the trench was backfilled. The pileswere embedded in competent bedrock. Because ofthe high water table in the Dietrich River areasouth of Atigun Pass, a sling system was used tosupport the pipe and to minimize excavation belowthe pipe. The piles were driven to bedrock at33.5 m. At another location a major through-cutwas made, the pipeline was supported on elevatedhardware, and the pipeline was left uncovered, 80a buried pipeline was changed to a fully restrainedelevated line.TABLE 1 Lengths of the three basic construction modes and soilconditions along the route of the Trans-Alaska Oil Pipeline.LengthMode Conditions mi kmConventional lxlrialThawed ground or thaw stablepermafrost 380 612Aboveground Thaw unstable permafrost 416 669Refrigerated burialThaw unstable permfrostwith access restrictions 4* 6800 1287*1.8 mi (2.9 km) refrigerated piping at pumping stations 1, 2, 3, 5,and 6 in addition to mainline piping.109

110Another technique that is being used moreconsists of simply lifting the pipe up to even outthe extreme downward curvature and backfillingwith a weak sandlcement slurry underneath the pipeto give continuous support. Naturally, this remedialwork is followed by careful monitoring. Inmost cases, the thaw bulb has already grown to agood portion of its total size, so any additionalthawing that might occur would be deep seated.Consequently, the need for further correction ofthe pipeline in these areas should be limited. Onthe south side of Atigun Pass, an area of thawedground was associated with flowing groundwater.The problem was solved by using mechanical refrigerationto refreese the ground and heat pipes tomaintain the frozen condition (Thomas et ala,1982).The elevated portion of the pipeline consistsof 77,732 pile supports. 'lbe piles are 46-cm-diametersteel pipes and are embedded to an averagedepth of 9.1 m. There are 17 different pile typesand they can be roughly grouped into five categories(see Table 1 of paper by Jahns). The resulcsof monitoring the piles supporting the abovegroundpipeline show that 0.6% of the sample settled morethan 9 cm, that 1.9% heaved more than 9 cm, andthat the thermal piles installed in thawed groundhad the greatest movement (Table 1 of Jahns paper).The 9-cm threshold was chosen because it wasthought that this much movement could be of concern;however, site-specific investigations haverevealed that very few minor problem occur withmovements of this mgnitude.There are 122,000 heat pipes installed alongthe pipeline to prevent excessive permafrost thawor frost heaving. The heat pipes are of a twophase,closed system containing anhydrous ammaniaas a working fluid. Monitoring the heat pipeswith infrared imagery has revealed that many ofthem are losing their effectiveness, probably becauseof blockage of the heat pipes by a non-condenaablegas. Gas blockage could ultimately causetotal failure of the heat pipe. Preliminary analysisindicates that the blockage is being causedby hydrogen gas presumably being formed by corrosioncaused by water or other contaminants leftinside the heat pipes during their manufacture.Figure 1 shows how the heat pipe functions and howthe accumulation of hydrogen gas in the top prtionof the pipe can limit the dissipation of heatinto the atmosphere. A relatively simple and inexpensiverepair technique has been developed,which uses a metallic halide ("getter" material)that absorbs hydrogen and, consequently, restoresthe heat pipes to a fully functional condition.The buried refrigerated pipeline mode wasutilized for 6 km of the main line and for approximately2900 m of buried pipeline at the northernpump stations. This mode consists of a brine-loopmechanical refrigeration system and Insulatedpipeline. The pipeline is insulated with polyure-HEAT PIPE-

111SELECTED PANEL SESSION REFERENCESClarke, E.S., Krzewinski, T.G., and Metz, M.C.,1981, Trans-Alaska Pipeline System syntheticallyinsulated workpad--An evaluation ofpresent conditions: Energy-Sources TechnologyConference and Exhibition, Houston,Texas.Ferrians, O.J., Jr., Kachadoorian, R., and Ereene,G.W., 1969, Permafrost and related engineeringproblem in Alaska: Washington, D.C.,U.S. Geological Survey Professional Paper678.Heuer, C.E., 1979, The application of heat pipeson the trans-Alaska pipeline: Hanover, N.N.,U.S. Army Cold Regions Research and EngineeringLaboratory, Special Report 79-26.Heuer, C.E., Krzewinski, T.G., and Metz, M.C.,1982, Special thermal design to prevent thawsettlement and liquefaction, Proceedingsof the Fourth Canadian Permafrost Conference,Calgary: Ottawa, National Research Councilof Canada, p. 507-522.Heuer, C.E., Caldwell, J.B., and Zamsky, B., 1983,Design of buried sea-floor pipelines for permafrostthaw settlement, & Proceedings ofthe Fourth International Conference on Permafrost,Fairbanks: Washington, D.C., NationalAcademy of Sciences, p. 486-491.Hwang, C.T., 1976, Predictions and observations onthe behavior of a warm gas pipeline on permafrost:Canadian Geotechnical Journal, V. 13,p. 452-480.Ivantsov, O.M., Semyonov, L.P. , Croty , F.E. , andFerrians, O.J., Jr., 1983, Problem of environmentalprotection during construction andoperation of pipeline systems in northern regions:11th World Petroleum Congress, London,preprint.Jahns, H.O., Miller, T.W., Pcmer, L.D., Rickey,W.P., Taylor, T.P., and Wheeler, J.A., 1973,Permafrost protection for pipelines, & Permafrost-- the North American Contribution tothe Second International Conference, Yakutsk:Washington, D.C., National Academy of Sciences,p. 673-684.Jahns, KO,, and C.E. Heuer, 1983, Frost heave mitigationand permafrost protection for a buriedchilled-gas pipeline, & Proceedings ofthe Fourth International Conference on Permafrosf,Fairbanks: Washington, D.C., NationalAcademy of Sciences, p. 531-536.Johnson, E.R., 1981, Buried oil pipeline designand operation in the Arctic - Lessons learnedon the Alyeska Pipeline, 37th PetroleumMechanical Engineering Workshop and Conference,Dallas, Texas, preprint.Lachenbruch, A.H., 1970, Some estimates of thethermal effects of a heated pipeline in permafrost:Washington, D.C., U.S. GeologicalSurvey Circular 632.Metz, M.C., Krzewinski, T.G., and Clarke, E.S.,1982, The Trans-Alaska Pipeline System workpad--Anevaluation of present conditions: &Proceedings of the Fourth Canadian PermafrostConference, Calgary, 1981 (Roger J.E. B r mmemorial volume): Ottawa, National ResearchCouncil of Canada, p. 523-534.Miller, T.W., 1979, The surface heat balance insimulations of permafrost behavior: Journalof Energy Resources Technology, v. 101, p.240-250.Myrick, J.E. , Isaacs, R.M., Llu, C.Y., and Luce,R.G., 1982, The frost heave program of theAlaskan Natural Gas Transportation System,American Society of Mechanical Engineers paper82-WA/NT-12.Nixon, J.F. Stuchly, J., and Pick, A.R., 1984, Designof Normal Wells pipeline for frost heaveand thaw settlement, & Proceedings of theThird International Offshore Mechanics andArctic Engineering Symposium, V. 3: NewYork, American Society of Wchanical Engineers,p. 69-76.Pearson, S.W., 1979, Therm1 performance verificationof thermal vertical support members forthe trans-Alaska pipeline: Journal of EnergyResources Technology, V. 101, p. 225-231.Thomas, H.P., Johnson, E.R., Stanley, J.M., Shuster,J.A., and Peareon, S.W., 1982, Pipelinestabilization project at Atigun Pass, &Proceedingsof the Third International Symposiumon Ground Freezing, Hanover, N.H., preprint.Wheeler, J.A., 1978, Permafrost thermal design forthe trans-Alaska pipeline, Moving BoundaryProblems (D.G. Wilson and A.D. Solomon,eds.): New York, Academic Press, p. 267-284.Williams, P.J., 1979, Pipelines and permafrost,physical geography and development in thecircumpolar North, & Topics in Applied Geography(D. Davldeon and J. Dawson, eds.):London and New York, Longman.

Environmental Protection of Permafrost TerrainPANEL MEMBERSJames E. Hemming (Chairman), Dames & Moore, Anchorage, Alaska, USANikolai A. Grave, Permafrost Institute, Siberian Branch, Academy of Sciences, Yakutsk, USSRCurtis V. McVee and Jules V. Tileston, U.S. hreau of Land Management, Anchorage, Alaska, USAHugh M. French, Departments of Geography and Geology, University of Ottawa, Ottawa, CanadaMax C. Brewer, U.S. Geological Survey, Anchorage, Alaska, USAPatrick J. Webber, Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado,USAINTRODUCTION AND A CASE STUDYJ.E. HemmingDuring the past decade, accelerated developmenthas occurred in the Arctic, resulting in arapid evolution of environmental controls andtechniques to minimize negative impacts duringconstruction. Essentially all of the circumpolarnations have experienced oil and gas explorationand development, pipeline construction, and increasedmining activity. The primary problems arerelated to the scarcity of gravel in some tundraareas, the sensitivity of permafrost soils to disturbance,and the disposal of drilling muds andother wastes in frozen soils. Recent research hasemphasized better understanding of the biologicaland physical characteristics of tundra ecosystemsand the development of low-impact techniques fortransportation systems and facilities. Ae resultsare published and the significance of various developmentactivities is better understood, regulationshave been changed and new guidelines andstandards have been developed.The panel papers that follow emphasize variousaspects of environmental protection of thepermafrost areas in the United States, Canada, andthe U.S.S.R. The panel acknowledges that environmentalproblems can be minimized or avoided by positiveapproaches to problem-solving early in theproject planning process. This point was alsodiscussed and described in a workshop held in 1980in Fairbanks to review steps necessary for terrainprotection during development (Brown and Hemming,1980).Several papers and reports present additionalinformation on environmental conditions and problemin permafrost regions (Armstrong. 1981; Gerasimov,1979; Grave, 1983; Hanley et al., 1981;National Research Council, 1980; Woodward-Clyde,1980).An example of the environment planning processis summarized below as an introduction to thispanel report. The process includes inventories ofboth the natural resources and the engineeringconstraints, mapping of sensitive areas. a preliminarysiting plan, and the detailed engineeringdesign.Natural Resources Inventory: Once a new projecthas been identified, but before the exact locationof facilities has been confirmed and thedetailed engineering design has been initiated,field resource inventories are conducted. Informationis gathered on bird, mammal, and fish occurrenceand sensitive habitat, endangered species,wetlands, and subsistence, recreation, andother land use patterns. These data are used tosupport applications for government permits and toprovide a basis for siting the project facilitiesso that they will cause the Least adverse impact.Engineering Constraints Inventory: Simultaneouslywith natural resource inventories, dataare collected by engineering geologists through acombination of aerial photo interpretation andfield surveys in order to delineate engineeringconstraints. Information on geotechnical factorssuch as grades, organic soils, patterned ground,solifluction zones, and aufeis areas is used todelineate constraints.Delineation of Sensitive Areas: When engineeringconstraints and natural resource inventoriesare complete, the results are integratedinto detailed maps of the sensitive areas.Preliminary Siting Plan: Preliminary sitingof facilities involves avoiding sensitive areas.When sensitive areas cannot be avoided, specialmitigation plans are prepared, The reduction ofenvironmental impact and mitigation planning are113

114FIGURE 1 A map of environmental and engineering constraints that were avoided during selectionof a transportation corridor alignment for the proposed Red Dog Mine Project, Alaska.an integral part of the permit process in theUnited States.Detailed Engineering Design: After preliminaryproject designs and mitigation plans havebeen reviewed and accepted by government agencies,a project can proceed to detailed engineering design.The above process was applied to the proposedRed Dog Mine, a world-class lead-zinc depositalong the Alaskan coast of the Chukchi Sea (Dawsh Moore, 1983). This project involved planningfor 110 to 130 km of road plus a new port, airfield,water storage reservoir, mine tailings disposal,mill, and housing facilities. The entirearea is underlain with permafrost with an activelayer about 0.5 to 1.0 m thick. Wildlife andfisheries resources are abundant and subsistenceactivities by local Eskimos are wel established.Regulatory agencies were most concerned aboutthe potential impacts of mine facilities on fishspawning and overwintering areas, endangered ortare wildlife, large-mammal overwintering areas,and wetland habitats. The mining company was mostconcerned about construction and maintenance costsrelated to the alignment of the transportationcorridors and h w the econodc feasibility of theproject would be influenced by the environmentaland engineering constraints.Natural resource and engineering constraintsinventories involved review of the literature andextensive field surveys by engineers, geologists,and biologists. Fish spawning, rearing, and over-wintering areas, as well as endangered species habitats#large-mammal overwintering areas, wetlands,patterned ground, areas of sheet flow, solifluction,and aufeis zones were identified anddelineated on 1:63,360 scale topographic maps.Once the individual natural resource values andengineering constraints had been delineated, acomposite msp was prepared. It was then possibleto select potential transportation corridors andto evaluate the comparative costs of construction.The interdisciplinary process applied in thiscase resulted in the selection of a transportationcorridor (Pig. 1) that would meet government perodtrequirements with the fewest potential environmentalimpacts and the lowest estimated constructioncost. This approach is being adoptedfor other development projects within Alaska.REFERBNCE SArmstrong, T., 1981, Environmental control in remoteareas: The case of the Soviet Northlandswith an Alaskan comparison: Polar Record,V. 20, p. 329-335.Brown, J. and Hemming, J.E., 1980, Workshop on environmentalprotection of permafrost terrain:Northern Engineer, V. 12, no. 2, p. 30-36.Dames 6 Moore, 1983, EnviroMtental baseline studies,Red Dog Project: Cominco Alaska, Tnc.Gerasimov, I.P., 1979, Protection of the environmentin northern Siberia: Izv. of USSR Acad-

115emy of Sciences, Ser. Geogr., no. 1, p. 45-52.Grave, N.A., 1983, Stability of the surface inmechanical disturbance associated with northerndevelopment: Polar Geography and Geology,V. 7, no. 3, p. 175-186.Hanley, P.T., Hemming, J.E., Morsell, J.W., Morehouse,T.A., Leask, L.E., and Harrison, G.S.,1981, Natural resource protection and petroleumdevelopment in Alaska: Washington,LC., U.S. Fish and Wildlife Service, BiologicalServices Program, FWSJOBS-80J22, andFWSJOBS~OJ~~. 1.National Research Council, 1980, Surface coal miningin Alaska: An investigation of the SurfaceMining Control and Reclamation Act of1977 in relation to Alaskan conditions:Washington, D.C., National Academy of ScienceS.Woodward-Clyde Consultants, 1980, Gravel removalstudies in arctic and subarctic floodplainsin Alaska: Washington, D.C., U.S. Fish andWildlife Service, Biological Services Program,pWSJO~S-80J08.

DEVELOPMENT AND ENVIRONMENTAL PROTECTION IN THEPERMAFROST ZONE OF THE USSR: A REVIEWN.A.GravePermafrost Institute, Siberian BranchAcademy of Sciences, Yakutsk, USSRCertain results of research into this problem all-union, regional, and departmental meetings, conwerepresented at the Third International Confer- ferences, and symposia (e.g. Okhrana okrazhayushcheyence on Permafrost in Canada and were publishedsredy 1980, Geokriologicheskiy progmz, 1980, 1982,in the proceedings both in English (Brown and Grave Inzhenerno-geokrilogicheskiye aspekty 1981; etc.),1979a, 1979b) and in Russian (Brown and Grave 1981). has encouraged the appearance 01- a number of envlr-Further progress in this direction has been omental protection reconmendations and manuals.achieved during subsequent years (1979-82) as this On the basis of the Permafrost Institute's investipaperwill demonstrate. This progress is reflected gations, VSYeGINGYeO and PNIIIS have produced anin particular by the passing of a number of govern- Interim manual on the laying of pipeZines fn thement Bills and regulations. In accordance with Abort71 (19801, which includes recommendations on theArticle 18 of the Constitution of the USSR, the selection of construction sites, requirements forSupreme Soviet of the USSR has enacted basic legis- engineering preparations, the use of thermal insullationon the use of waters, forests and mineral ators, recommendations on methods of biologicalresources. In the Soviet Union we have begunrestoration of disturbed areas, and the use offormulaKing standards for environmental protection thermal piles on gas pipelines, and proposals aswhich will regulate the interaction of man and to his the regulation of the construction and operationenvironment; these standards are divided into of installations. A map of the natural-area comsectionson "Soil", "Landscapel', and "Land". With- plexes (landscapes) of the north of Western Siberiain this last section the sequence of restoration is included in an appendix.and revegetation of land disrupted due to human Specific needs in terms of environmental protecactivitiesis specified.tion in the North were the cause for subsequentA series of special measures on environmental intensification of scientific research with a viewprotection in the tundra zone in and the area of to establishing more precise criteria to as thethe Baikal-Amur railway was first passed 1978 in degree of impact caused by human activities on theby a resolution of the Central Committee of the environment, and the latter's response. It vasCommunist Party and by the Council of Ministers of also important to determine precisely the permafrostthe USSR, entitled "On additional measures to rein- aspects of the environmental protection problem,force environmental protection and to improve the embracing not only the land surface but also water,use of natural resources." Responsibility for the air, flora and fauna. This did not simplify thestate of the natural environment and implementation problem for permafrost scientists who are startingof the appropriate measures was entrusted to to focus special attention on the sensitivity ofgovernment bodies, and at the administrative level the surface in permafrost areas to human activitiesthey are to be implemented by the local Soviets of (Grave 1980), since the actual concept of the sur-People's Deputies.face includes essentially all the main componentsAt a time of accelerated development of the of landscapes.northern and northeastern regions of the USSR The main approach in solving the problems ofthese measures have played a positive role in surface stability involves prediction of changesenvironmental protection. Environmental Protection in the permafrost conditions and the developmentdepartments have been created within the main of cryogenic processes as a consequence of humanministries operating in the permafrost regions; disturbance of the surface. The problem of geotheirtask is to implement the environmental cryological, or more accurately geological, predicprotectionmeasures with regard to industrial and tion in connection with the solution of problems oftransport projects and to monitor their effective- environmental protection in the North has becomeness. The Soviet of Ministers of the Yakutsk ASSR the main focus of permafrost studies in the pasthas passed a resolution to regulate the movement few of years. Researchers are striving to obtaintracked vehicles in summer in the nine northern quantitative and not just qualitative predictionsdistricts of the Republic. Voluntary societies for and, in connection with this, the quantitativeenvironmental protection have been established in characteristics of the original components of thethe republics, krays and oblasts in the northern landscape.areas of the country and in some areas evenTheoretical investigations by GrechishchevUniversities of Environmental Protection. They (1982a,b), based on the results of 15 years ofhave been pressing for widespread popularization of research in Western Siberia, allowed to him conthebases for rational land use in areas, settle- struct a functional thermodynamic model of thements and towns experiencing development.environmentallspatial complex (i.e. the landscape)Widespread discussion of the results of scien- in a permafrost area. It takes into account thetific investigations into environmental protection relations between thermophysics (changes in thein the North, which were undertaken in the at 1970s thermal and moisture conditions of the materials)116

117TABLE 1 Changes in northern taiga landscapes caused by disturbances of the surface during constructionalong the line of the SaLekhard-Igarka Railway (adapted from Grechischev et 1983). al. Natureof disturbance and changes inthe major landscape components 22 years after building of therailroad.Topography Vegetation SoilsEngineering-geocryological conditionsPermafrost Mean annual ExoRenic-distribution temp. Active layer processesTotal removal Replacement of Removal of Lowering of Rise of Increase in active Thermokarstof vegetation sparse shrub/ peat layer permafrost 0.5OC layer depth by 2-3 at sites withcover and level- sphagnum forest to depth table by times; in some segregationling of surface by sparse willow/ 0.4 of m 3-3.5 m places giving ice; seasonbirchforest way to a a1with shrubs, seasonallygrass and frozenPolitr-ichwn1-3 m highand mechanics (development of cryogenic physicalgeologicalprocesses). This model is seen by theauthor as a base for quantitative predictions ofchanges in permafrost conditions resulting fromman-induced impacts on the environment.the physical-geographical analog consists of comparingthe landscape under study with one alreadydeveloped, and which experienced the same sequenceof development and contains identical components.The method involves the following stages: assemblyThe model includes such factors as hydrometeoro- of base-line information by means of a geocryologicalaspects, the composition and properties of logical survey; investigation of disturbed andthe vegetation cover and soil, the local topography, undisturbed sections of the landscape; analysis ofand technogenic factors. The latter include: heat the landscape from aerial photos flown in differentflux into the ground from engineering installations, years; selection of comparable sites for long-termdisturbance of vegetation and soil cover during obsenration; and finally, analysis of the assembledconstruction or operation of those installations; data and compilation of predictive tables and maps.changes in the surface drainage due to artificial In the previously cited monograph (Grechishchevinundation or drainage; and changes in the surface et al. 1983) the methodology of studying mantopography(embankments or pits).induced changes in landscapes (environmental/spatialHowever, there are some problems associated with complexes) by way of the stages listed above isthe construction of a computerized mathematical presented in detail. Predictions of changes in themodel in this case; these are associated with the temperature regime and of seasonal freezing andfact that the interrelations between the tempera- thawing of the ground both in the first few yearsture field, moisture content of the soils and after the start of development, and also 15-20 yearsthermokarst have not been determined with and the thereafter, and predictions of cryogenic processesfact that information is also lacking as to some of (themkarst, thermally induced settlement, frostthe other interdependences between components of heave and frost cracki.ng) are examined in detail,the landscape. Simplified mathematical models can Examples of predictions of changes in landscapebe used in predictions where only one-way links conditions over the long term as a result ofbetween components are considered, e.g. in the case development in northern West Siberia have also beenof the removal of the vegetation cover without any cited in articles (Moskalenko 1980, Grechishchevsubsequent restoration.and Mel'nikov 1982, Grechishchev et al. 1983). OverExamples of qualitative, semi-quantitativean area of about 10,000 km2 60 types of geobotanical(statistical-analog) and quantitative (physical- units were identified and studied using geocryomathematical)predictions of changes in geocryo- logical and landscape mapping and long-term fieldlogical conditions in the main oil-and-gas fields observations. Over part of the area the vegetationof the north of Western Siberia, i.e. on the inter- cover, the microrelief and the uppermost peatfluve between the Pur and the Nadym and the southern horizons were removed.part of the Taz Peninsula, are cited in mono- the Table 1 presents examples of changes in landscapegraph by Grechishchev et aZ. (1983) as well as in and in geocryological conditions as a result ofa number of articles (Grechishchev and Mel'nikov disturbance of the surface along the line of the1982, Moskalenko 1980). The main method of geo- Salekhard-Igarka railroad in terms of the situationcryological forecasting of the sensitivity of thesurface to man-induced impacts is that of thephysical-geographical analog (Mel'nikov, P.I.,et al. 1982, MoskaLenko and Shur 1980), Maninduceddisturbances of the landscape may be dividedinto permanent (e.g. repeated use of land for22 years after construction. In practice the disturbancesdi.d not differ from those within the areaunder development being studied and may serve as abaseline for geocryological predictions.The section of the abandoned railway is locatedon a marine plain, composed of loams covered withagriculture), periodic (removal of undergrowth along peat. Islands of permafrost coincide with peatpipelinerights-of-way) and impulsive (on one lands, palsas and bogs. Several recommendations asoccasion and for only a short time). The method of to development of the area and as to protection of

118the environment have been formulated, with applica- Eastern Siberia (1967-1975) observations weretion to landscapes of a region with various degrees carried out at experimental sites on solifluctionof sensitivity to human activities (Grechishchev and the destruction of the sides of the pits.et al. 1983). In accordance with these predictions Some recommendations were made as to measures todevelopment of even well drained sections-slopes,hillocks and frost-heave mounds-must lead to theimprove the technology of open-pit mining, especiallywith regard to thermal amelioration of icedevelopmentof thermokarst and thermal erosion; rich loams (Olovin 1979) *this will necessitate the fixing of the disturbedA classification of landscapes has been workedsections with vegetation or the avoidance ofout for estimating engineering conditions in theparticularly ice-rich sediments.permafrost areas along the Baikal-Amur RailwayThe detailed landscape and geocryological char- (Mikhaylov 1980). The first results of long-termacteristics of the West Siberian gas-bearing observations in the eastern part of the BAM zoneprovince have been presented in two monographs have been published (Zabolotnik and Shender 1982,(Mel'nikov, Ye. E., et al. 1983a, b).Balobayev et al. 1979). The observations were madeA detailed survey of geocryological and thermo- in 1978 in theupper Zeya b%-sin (elevation 300 m)physical site investigations of the upper hori- in an area with widely developed &, i.e. thickzons of the permafrost and of the active layerwith a view to geocryological forecasting inconnection with man-induced disturbances of thesurface was published by Pavlov and Shur (1982).Long-term Observations were carried out underpeat bogs underlain with ground ice. Removal ofthe moss cover led to an abrupt increase in thedepth of summer thaw and to the development ofthermokarst; there was also a tendency for the thinbodies of permafrost in this southern area tovarious physical geographical conditions: ondegrade. Removal of snow in winter not only haltedarctic tundra, forest tundra and taiga; in continentaland maritime areas: and in areas ofContiIlUOUE permafrost and in areas near itssouthern boundary. These observations not onlyconfirmed a number of earlier conclusions butplso produced new results.The results of regular, systematic, long-termobservations on various sites, both natural andthis process but also provoked a marked lowering ofthe temperature of the permafrost, down -4 to and-5OC.In the northern taiga zone of Western Siberia,i.e. near the southern limit of permafrost, experimentalobservations have revealed that removal orcompaction of the snow cover on forested, welldraineddivides and on swamps, led to the formationdisturbed, in the area of the Urengoy gas field of pereZeAoks. Cutting of forests on high floodhavealso been published (Chernyad'yev 1980).Using Leibenzon's methods, fairly simple relationshipsfor calculating the depth of thaw werederived, taking into account the ground surfacetemperature, the length of the freeze-thaw period,the insulating properties of the Vegetation andplains and levelling of sites on hummocky surfacesled to an increase in the thaw depth and to thermokarst.Frost cracking of the ground occurred onlyin very cold surfaces, at temperatures below -23Oto -25OC on peatlands and sands, and below -15'Con hams (Grechishchev et al. 1980).soil covers, latent heat and the thermophysical Investigations of landscape and permafrost incharacteristics of the sediments. Monograms were Central Yakutia associated with predictions as tocompiled which allow one to calculate the ground the suitability of areas of the taiga for clearancetemperature depending on the thermal resistivity far agricultural purposes, were carried out usingof the Vegetation and soil covers and the tempera- cryolithological and thermophysical techniques.ture of the surface.These Observations confirmed the major roleDespite the high ice content of the underlyingmaterials, removal of the vegetation cover andplayed by the snow cover in the thawing of the ploughing of sites in meadowlands on the highground; snow accumulation on sites where peat and floodplain of the Amga River did not produce inmosshad been removed markedly increased the depth tense thermokarst because of the poor insulatingof thaw and raised the temperature of the ground. properties of a meadowland vegetation. By contrastBy contrast gravel pads dumped a on peatlmoss covercooled the ground. Beneath the pad the peatremoval of the forest on older, high terracescontaining massive ice wedges led to an abruptbecomes moist and the snow blows off the pad in increase in the depth of summer thaw and to thewinter. This reduces the depth of thaw beneath development of thermokarst. Only a dry climate,the pad (Chernyad'yev 1980, Chernyad'yev andas a rule, will stop this process in the earlyAbrashov 1980, Shur et d. 1982, Chernyad'yevstages of development (Turbina 1982). Evidently1982, Kondrat'yev et al. 1979).dry summers are associated with generally minorOther observations also point to the important disturbances of the relief along the buried gasinfluence of the snow cover on the temperature of pipeline running from Taas-Tumus to Yakutsk alongthe surface layers of the ground. Thusthe section in the vicinity of the Kenkeme andShversov (1982) reached the conclusion that the Khanchaly rivers (Turbina 1980) .most unstable soils in terms of their thermo- Investigations of areas through which gas pipedynamicsare those in tundra areas with little orno snow cover. These sites cool drastically duringlines have been laid in the north of WesternSiberia, in Yakutia and Noril'sk at have revealedthe cold season but warm up drastically in summer. that man-induced disturbances of the surface areAt latitudes of 66-72' and farther north the soil limited to sections with ice-rich sediments, wherebeginsto thaw even with air temperatures well as along sections with ice-poor sands, which arebelow zero in late spring. This is confirmed by widespread in these areas, serious surface disturbfieldobservations at Cape Kharasavey (Yamal Penin- ances did not occur, and for the greater part thesesula) over the period 1978-1980 (Sergeyev 1982).In the vicinity of the Kular minethe north ofsections are experiencing natural revegetation(Sukhodol'skiy 1980, Spiridonov and Semenov 1980).

119A somewhat dif€erent approach to the compilation tures in the water added to thaw the deposits, theof predictive maps is also quite widespread. The introduction of gases, etc. (Perl'shtein 1979,object of the mapping is the ground materials rather Balobayev et al. 1983). Al of these operationsthan landscapes, although the physical geographical disrupt the biological productivity of the ecoconditionsaffecting the properties of the sedi- system and aggravate erosional processes, slopements still play a crucial role in this method. denudation and stream pollution. Hence DomenikA method has been proposed for evaluating permafrostconditions for the early stages of planningabove-ground structures and for assessing theirimpact on the landscape. The heat inertia of thefrozen materials and the peculiarities of cryogenicprocesses both under natural conditions and underconditions of man-induced disturbance, form thebases for compiling evaluation maps. The cryogenicprocesses are divided into three categories: stable(weak activity), resiliently stable (showingseasonal activity) and unstable (progressivelydeveloping). The latter category involves thermokarst,thermal erosion, landslides, solifluctionand frost heave. Here the ice content of thepermafrost materials represents the main factor inevaluating the stability of the area (Garagulyaand Parmuzin 1980, 1982, Demidyuk 1980, Garagulyaet al. 1982, Baulin et al. 1982, Garagulya andEordeyeva 1982).A quantitative method €or evaluating the complexityof engineering-geocryological conditionshas been proposed; it examines these conditionsas a system of inter-linked components. A master are being conducted in the tundra zone. Multiplanfor evaluating these systems has been develop- disciplinary studies of the heat balance of anded. The final stage of the operation involvesspecial mapping of the engineering geology of thearea.This method has been used in one of the areaswhere pipelines are being built in the North ofWestern Siberia. It was possible to demonstrategeobotany have been carried out in the arcticregion of Western Siberia along the lower reachesof the Bol'shaya Kheta. They revealed that solarradiation and heat were adequate for the growth ofsown grasses (Pea) and Gramineae; this proves thefeasibility of revegetating disturbed landscapes inthe influence of various environmental factors on the tundra zone (Skryabin and Sergeyev 1980).the cost of planning, construction and operation Investigations of revegetation in the extreme northof a pipeline where special environmental protec- of the Yenisey.region have demonstrated that thetion methods were used. Areas with varying com- most active native anchoring plants on disturbedplexities of engineering-geological conditions tundra are CaZamagrostis kppZan&a (reed bentwereidentified on a map were and categorized as grass), Festucu etc. (Skryabin 1979). The resultssimple, mpderately complicated and very complicated of multi-disciplinary investigations into soils,(Bondariye and Pendin 1982).man-induced disturbances and the conditions forPredictive investigations of permafrost are regrowth of various plants on the tundra of theincreasingly being used in areas of major develop- Polar Urals have been published. Types of soilsment in the North (Kudryavtsev 1982). It has been have been identified in terms of suitability forrevealed that to some extent the difficulties of revegetation, and recomnendations have been made asdevelopment in the permafrost zone associated with to improving the properties of the soil, the seedtheproblems of environmental protection have been ing of grasses and the planting of shrubs and treesexaggerated. Both cartographic and field investi- (Vital' 1980, Liverovskaya 1980, Smironov et al.gations have revealed that the areas where develop- 1980) .ment would lead to intense development of cryogenicprocesses had been exaggerated (Pavlov and ShurFires, the felling and rooting of up trees,ploughing, and many other types of development are1982). The unstable areas, as a rule, occupy about among the causes of soil disturbance and degrada-25-50% of the surface of the areas investigated in tion. In Magadan oblast' soil studies have beenthe most sensitive areas of the Arctic (Grave et al. carried out in the tundra, the taiga and the alpine1982). This aspect testifies to the clear benefits tundra. The soils of this region were classifiedof preliminary geocryological investigations inareas to be developed, in terms of reducing thecosts of environmental protection measures.both on the basis of biological productivity and ontheir degree of vulnerability to the types ofdisturbance listed above. The results of theseIt should be noted that very little attention studies is are useful for planning developments andpaid to the injurious impact of placer mining onthe landscapes of the North. Both natural andartificial methods are used to thaw the placerfor achieving optimum land use (Sapozhnikov 1980).Investigations are continuingthe impact ofurban development on geocryological conditions. Atdeposits once the vegetation and the surficial soil Labytnangi, on the Arctic Circle on the lower Ob',layer have been removed; these include sluicing of construction began in 1949 with small, closelythe surface, intensification of percolation intothe deposits, the introduction of chemical admix-et al. (1979) have focussed particular attentionon the need to plan for revegetation measures toprevent erosion during the planning of such miningoperations. Treatment of the mining effluentsand both engineering and biological reclamationmust be seen as inalienable parts of mineralextraction operations. It is recommended inparticular that dredge tailings be dispersed usingauxiliary equipment. However, in a number of casesmajor changes in the surface near borrow pits dueto slope processes and the development of lifeless''lunar landscapes" have nor occurred. Thermokarstdepressions have in some cases been colonizedby Arctogracis and by Equisetum arvense while onslopes and baydzherakhy thick growths of arcticgroundsel have appeared. Additional sprinkling ofthe surface leads to the appearance of grasses andafter 6-8 years turf will appear in such areas inthe Arctic (Olovin 1980).The problem of revegetation of areas disturbedby development continues to absorb the attentionsof northern researchers. The major investigationsspaced buildings without ventilated foundations.Removal of the trees and grass cover, and the

120TABLE 2Landscape changes in the forest tundra zone caused by disruptions resulting from exploratorydrilling for gas (adapted from Grechishchev et al. 1983). Characteristics of disturbances andchanges in the major components of the landscape, 7-10 years after well was drilled.Topography Vegetation SoilsEngineering-geocryological conditionsPermafrost Mean annual Active layer Exogenicdistribution temp. depth processesSubsidence Replacement of Removal of No changes Rise of 1°C Increase by Thermalaround well sparse forest peat and recorded in depres- 150% erosionsites; gully- with shrub and organic horizon; sionsing on slopes lichen communi- reduction ofties with grass/ soil moisturemoss communities by 50%accumulation of snow in yards led initially to the Thus, for example, it is proposed that several yearsdevelopment of thermokarst, thermal erosion and the prior to construction one should remove the vegeformationof swamps. Improvements in buildingtechnology, dispersal of the buildings, the of usetation cover and drain the site in order to producea safe construction site (Grigor'yev 1979, Sukhodventilatedfoundations and gravel pads led to the rovskiy 1979). Alternatively it is proposed thatelimination of the destructive processes cited one should place gravel pads about 1 m thick on theabove (Stremyakov et al. 1980). The reverse phen- tundra surface and at the same time construct aomenon, i.e. disappearance of the permafrost, wasrecorded in the recently-built town of Ust'-Ilimsk;this was associated with the southerly location ofthis new town and a better building design. Theformation of pereZetoks has been recorded in thecase of temporary, poorly built buildings(Maksimova et al. 1980).With the development of towns in the North, andsurface drainage system; the pads should be mainlylaid in winter (Konstantinov 1979).For conditions prevailing in Central Yakuriaexperiments have led to optimal regimes for channelirrigation of meadows which will eliminate bog formationand the rise of the permafrost table, aswell as salinization (Mel'nikov and Pavlov 1980).To combat the latter, both on agricultural land andalso in association with agriculture, serious con- especially in urban areas, it is proposed thatcerns are being provoked by the process of second- cryopegs (brine solutions) be replaced with freshary salinization of soils and sediments by industrialand domestic waste water. Increased minerwater,which will freeze to produce an impermeablefrozen layer (Mel'nikov, P.I., et al. 1982).alization of suprapermafrost water and ground water A schematic map has been compiled with a view to(up to 300 g/R) has led to the thawing of sediments achieving a very general assessment of the degreeto depths of several meters; this threatens the of surface stability in areas under development instability of buildings and menaces the natural the permafrost regions of the USSR. It classifiesvegetation cover as well as crops (Anisimova areas as surfaces which are predominantly severely1980, 1981).unstable, slightly stable and relatively stable, inInvestigations are under way and recommendations terms of man-induced thermokarst, since thisthehave been made with regard to protecting the perma- cryogenic process most hazardous to the environmentfrost from thawing around drilling sites. As aresult of thermokarst around drilling sites in the(Grave 1982).The map identifies areas most vulnerable togas fields of Western Siberia, pits up to 10 m deep development, where one must pay greatest attentionand 3-4 m in diameter have been recorded. Table 2 to the possible consequences; this mainly involveslists the changes in the landscape and in geocryo- areas with ice-rich permafrost. Ground ice meltslogical conditions around drill sites in thedifferently under different physical-geographicalnorthern taiga zone, on well-drained forest tundra. conditions. Thus under severe continental con-This phenomenon is also known from the American ditions, where in summer.evaporation exceeds pre-North. In the USSR insulations have been developed cipitation, or in the very cold conditions ofwhich operate on the principle of natural cold arctic deserts where there is massive Pleistoceneaccumulation to prevent the thermokarst phenomena ground ice, melting of that ice when the vegetationjust described. Drilling muds of a special composi- and soil cover are destroyed, occurs only ation and stricter regulations as to their use have limited scale. Compilation of maps of ice contentalso been recommended, in order to reduce pollution in the permafrost represents a major task for theof the environment (Orlov et al. 1982, Akhmadeyev immediate future. The maps of distribution of1982). Disruption of the surface around gas flare- ground ice and of thaw-subsidence in permafrost,offs have been examine-d and calculations to deter- compiled for the uppermost 10 m layer €or the northmine the scale of the problem have been recommended(Polozkov et al. 1982).In the case of the tundra zone preliminary preparationof areas to be developed has been recommended,prior to the erection of any structures;these precautions would obviate subsequent disruptionof the surface due to cryogenic processes.of Western Siberia (Trofimov et al. 1980) may serveas a model for such maps.Future investigations must concentrate not onlyon the rather labor-intensive methods of physicalgeographical evaluation, which have been most widelyused in Western Siberia, but also on perfectingmathematical models, taking into account both

12 1direct and inverse relationships between components izyskuniy [Geocryological prediction and perofthe landscape.fecting of engineering exploration]: MOSCOW,It is also essential to develop specific environ- Stroyizdat, p. 32-54.mental protection measures for the permafrost areas. Chernyad'yev, V. P., 1982, Investigations of heatexchange in freezing and thawing sediments atthe urengoy hospital, fi Temnika pochv i gornykhLITERATUREAnisimova, N. N., 1980, Cryogenic hydrogeochemicalchanges in alluvial deposits associated with(AN SSSR),p. 26-34.development in Central Yakutiya, in OkhranaChernyad'yev, V. P., and Abrashov, B. A., 1980, Theokruzhayushchey sredy p e osvvyenE oblastithermal regime of sediments on experimentalmnogoZetnerneraZykh pomd [Environmental protec- sites, & Geokrtologicheskiy prognoz i sovertionand development of the permafrost zone]: shenstvovaniye inzhenemykh {syskan-i.y [Geocryo-Moscow, Nauka, p 107-111.logical prediction and the perfecting of engin-Anisimova, N. N., 1981. Kriogidrogookhimicheskiyeeering exploration]: Moscow, Stroyizdat, p.osobennosti merzZoy zony [Cryohydrogeochemical5-31.peculiarities of the permafrost zone]: Novosi- Demidyuk, L. M., 1980, The problem of rationalbirsk, Nauka, 152 p.utilization of engineering-geocryologiczlAkhmadeyev, R. G., 1982, Some questions of envir-resources, & Okhrana okruzhayushchey sredy prionmental protection associated with well drilling osvoyenii 0bZast-i mnngoZetnemerzZykh porodin areas of the Far North, & GeokrioZogicheskiy [Environmental protection in association withprognoz v osvaivayemykh rayonakh Kraynego Severa development of the permafrost zone]: Moscow,[Eeocryological prediction in areas beingNauka, p. 42-50.developed in the Far North]: Abstracts of papers, Domenik, 0. P., Martsinyuk, B. F., and Payusova,Moscow, VSYeGINGYeO, p. 187.Ye. A., 1979, Technology and ecological conse-Balobayev, V. T., Zabolotnik, S. I., Nekrasov, I .A., quences of dredging operations, & TekhnogennyeShastkevich, Yu. G., and Shender, N. I., 1979,Zandshafty Severa i ikh rekuZ'tivatsiya [Techno-Dynamics of ground temperatures in northerngenic landscapes in the North and their revege-Priamur'ye in association with development of thearea, & Tekhnogennye Zandshafty Severa i ikhlWkUZ'tiVatSiyQ [Technogenic landscapes in theNorth and their revegetation]: Novosibirsk,Nauka, p 74-88.Balobayev, V. I., Pavlov, A. V., and Perl'shtein,G. z., 1983. Teplofizicheskiye issZedovaniyakriolitozony Sibiri [Thermophysical investigationsin permafrost in Siberia]: Novosibirsk,Nauka, 213 p.Baulin, V. V., Dubikov, E. I., Uvarkin, Yu. T., andMinkin, M. A., 1982, Problems and methods ofgeocryological forecasting in prospecting, j+Ceokriologicheskiy prognoz v osvaivayemvkhrayonakh Kraynego Severu [Geocryological predictionin areas being developed in the Far North]:Abstracts of papers, Moscow, VSYeGINGYeO, p.14-19.Bondariye, G. K., and Pendin, V. V., 1982, Methodsof quantitative evaluation of engineering-geologyconditions and of special engineering-geologymapping, Inzhenernaya geologiya, No. 4, p.82-89.Brown, J., and Grave, N. A,, 1979a, Terrain dis-*turbances and ground temperature regimes,Proceedings of the Third International Conferenceon Permafrost: Ottawa, vol. 3.Brown, J, and Grave, N. A., 1979b, Physical andthermal disturbance and protection of permafrost, CRREL Spec-iuz Report 79-5,Brown, J., and Grave, N. A., 1981. Narusheniyepoverkhnosti i eye zashchita pri osuoyeniiSeVem (Disturbance and protection of thesurface in connection with development in theNorth]: Novosibirsk, Nauka, 87 p.Chernyad'yev, V. P., 1980, Prediction of geocryologicalconditions associated with the disruptionof natural conditions, & GeokrioZogicheskiyprognoz C sovershenstvovaniye inzhenernykhporod u khoZodnikh rayonakh [Themam- aspects ofsoils and rock in cold regions]: Yakutsk, PermafrostInstitute (IM), SO USSR Academy of Sciencestationl: Novosibirsk, Nauka, p. 113-117.Garagulya, L. S., and Gordeyeva, G. I., 1982,Classification of changes in natural conditionsfor engineering-geology evaluations of terrainin connection with pipeline construction, Inzhellrernaya geohgiya, no. 2, p. 106-113.Garagulya, L. S., Kondrat'yeva, K. A., and Maksimova,L.N. 1982, Predictive geocryological maps atthe stages of planning and regional exploratoryinvestigations, & GeokrioZogicheskiy prognoz vosvaivayemykh rayonakh Kraynago Severa (Geocryologicalprediction in developing areas of theFar North]: Abstracts of papers, Moscow,VSYeGINGYeO, p. 36-39.Garagulya, L. S., and Parmuzin, S. Yu., 1980, In-dices for evaluating sensitivity of land tochanges in natural factors and to human activitiesin the permafrost zone, Merzzotnye issledovaniya,Izd-vo MGU, vol. 19, p. 53-59.Garagulya, L. S., and Parmuzin, S. Yu., 1982,Methods of evaluating permafrost conditions atrhe early stages of planning above-groundstructures, Inzhenernaya geozogiya, No, 4, p.98-107.GeokrtoZogicheskiy prognoz i sovorshsn&vovuniyeinzhenernykh izyskaniy (Geocryological predic-tion and perfecting of engineering exploration],1980: Moscow, Stroyizdat, 199 p.Geokriologicheskiy prognoa v osva-ivayemykh rayonakhKraynego Sevcra [Geocryological prediction indeveloping areas of the Far North]: Abstractsof papers given at an Interdepartmental Conference,9-11 February 1982: Moscow, VSYeGINGYeO,204 p.Grave, N. 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I122v obZasti vechnoy rnerzZoty [Sen sitivi .ty of thePermafrost con ditions in the Yenisey va 1 leysurface to human activities in the permafrost (Dudinka rayon) and changes in them associatedzone]: Yakutsk, IM SO AN SSSR, p. 6-12.with human activities, & xakhnoyennye landshaftyGrave, N. A., 1982, Sensitivity of the surfaceSevera i ikh rekuZ'tivatsiya [Technogenic landtomechanical disturbance associated with devel- scapes in the North and their revegetation]:opment in the North, Izvestiya AN SSSR, seriyaNovosibirsk, Nauka, p. 89-97.geogpafieheskaya, no. 6, p. 54-62.Konstantinov, I. P., 1979, Gravel pads as a techno-Grave, N. A., 1983, A geocryological aspect of the genic cover and a5 a building foundation, inproblem of environmental protection, & Proceed- Tekhnogennye Zandskfty Severu i ikh rekulrings of the Fo'ourth IntemationaZ Conference ontivatsiya [Technogenic landscapes in the NorthPernufrost, Washington, DC, National Academy ofand their revegetation]: Novosibirsk, Nauka,Sciences, p. 369-373.p. 62-73.Grave, N. A,, Mel'nikov, P. I., and Moskalenko, Kudryavtsev, V. A., 1982, Theoretical and methodo-N. G., 1982, Geocryological problems in envir- dological bases for geocryological prediction,onmental protection in association with thein GeokrCoZogicheskiy prognoz u osvaivayemykhdevelopment of oil and gas fields in the perma- rayonakh Kraynego Severa [Geocryological predicfrostzone, & CeokrioZogicheskiy prognoz trtion in developing areas of the Far North]:osvaivayemykh rayonakh Kraynego Severa (Geocryo- Abstracts of papers, MOSCOW, VSYeGINGYeO, p.logical prediction in developing areas of the 3-6.Far North]: Abstracts of papers, MOSCOW,Liverovskaya, 1. T., 1980, Changes in the proper-VSYeGINGYeO, p. 32-36.ties of soils in the eastern foothills of theGrechishchev, S. Ye., 1982a, Some problems inPolar Urals and adjacent plains, connected withgeocryological prediction, Inzhenernaya geol,og-l-:,peline construction, & OkhrUnQ okruzhayush-Zyu, NO. 3, p. 3-13.;hey sredg pri osvoyenii obZasti mnoyoietne-Grechishchev, S. Ye., 1982b, Theoretical questions merzlykh prod [Environmental prOteckiOn inin modelling cryogenic landscapes, & Geokrio-association with development in the permafrostZogicheskiy ppognoz v osvaivayemykh rayonakhzone]: Moscow, Nauka, p, 116-121.Kraynego Severa [Geocryological prediction in Liverovskiy, Yu. A., Popov, A. I., and Smironov,developing areas of the North]: Abstracts ofV. V., 1980, Revegetation of natural landscapespapers, Moscow, VSYeGINGYeO, p. 46-47.disturbed as a result of human activities, &Grechishchev, S. Ye., Krishuk. 1,- N. , Nevechera,Okhrana okmzhayusheheu sredu pri osvo,yzlen

II123Mikhaylov, N. A., 1980, Classification of landscapesduring evaluation of engineering geology conditionsin the BAM zone, in Geokriologieheskiy prognozi sovershenstvovanig inzhenernykh izyskaniy[Geocryological prediction and perfecting engineeringexploration]: Moscow, Stroyizdat, p. 149-166.Moskalenko, N. G., 1980, Landscape identificationof engineering geology conditions for predictionsof changes due to the impact of human activiti,es,in MersZotnye issZedovaniya v osvaivayemykhrayonakh SSS8 [Permafrost investigations indeveloping areas of the USSR]: Novosibirsk,Nauka, p. 8-18.Moskalenko, N. G., and Shur, Yu. P., 1980, Typicaldisturbances to environmental complexes in theNorth of Western Siberia under the influence ofpipeline construction and predictionstheirdynamics, fi Okhrana okruzhayushchey sredy priosuoyenii obZasti mnogpletnemerzlykh porod[Environmental protection in association with thedevelopment of the permafrost zone]: Moscow,Nauka, p. 71-78,to their preservation and rational utilization,- in Geografiya i genezis pochv MagadunskoyobZasti [The geography and genesis of the soilsof Magadan oblast']: Vladivostok, p. 161-168.Sergeyev, B. P., 1982, Beat and moisture exchangebetween the soil and the atmosphere in the areaof Cape Kharasavey (Yamal Peninsula), & Termikapochv i gornykh porod v khoZodnikh rayonakh[Thermal aspects of soils and rocks in coldregions]: Yakutsk, IM SO AN SSSR, p. 15-26.Shvetsov, P. F., 1982, Thermodynamic criteria forthe stability of soils and sediment complexesin the Subarctic, & GeokrioZogicheskCy prognozt, osvaivayemykh rayonakh Kraynego Seuera (Geocryologicalprediction in developing areas ofthe Far North]: Abstracts of papers, Moscow,VSYeGINGYeO, p. 6-8.Shur, Yu. L., Pavlov, A. V., and Chernyad'yev, V.P,, 1982, Some results of field investigationsof the regime of permafrost conditions in developingoil-and-gas areas in the permafrost zone,in Geokl-ioZogicheskiy prognoz v osvai va yemykhrayonakh Kraynego Severa [Geocryological predic-Okhrana okruahayushchey sredy pri osvoyenii obZasti tion in developing areas of the Far North]:mnogoZetnemerzZykh porod [Environmental protection Abstracts of papers, Moscow, VSYeCINGYeO, p.in association with development in the permafrost 24-28.zone] 1980: %scow, Nauka, 110 P.Skryabin, S. Z., 1979, Investigations into bio-Olovin, B, A,, 1979, The dynamics of re-arranginglogical restoration of tundra disturbed by humanlandscapes in connection with the exploitation of activities, in the Yenisey Far North, &Tekhnodepositsin the tundra zone, Te'ekhnogennyeingennye Zandshafty Seuera i ikh rekuZ'tivatsiyaZandshafty Savera i ikh rekul'tivatsiya [Techno-(Technogenic landscapes of the North and theirgenic landscapes in the North and their revege- revegetation]: Novosibirsk, Nauka, p. 51-61.tation]: Novosibirsk, Nauka, p. 98-112.Skryabin, P. N., and Sergeyev, B. P., 1980, WaterOlovin, B. 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S., 1982, Measures to protect theEnvironmental disturbance and the first stagespermafrost around well-heads, in GeokrioZogiche-of re-establishment of soils and vegetationskiy prognos v osvaivayemykh rayonakh Kraynegocovers in association with some forms of linearSevera [Eeocryological prediction in the develop- installations, & Okhrana okruzhayushchey sredying areas of the Far North]: Abstracts of papers, pri osvoyenii oblasti mnogoletnemerzlykh porodMoscow, VSYeGINGYeO, p. 198.[Environmental protection associated with thePavlov, A. V., and Shur, Yu. P., 1982, Thermo-development of the permafrost zone]: Moscow,physical site investigations of the upper layersNauka, p. 121-127.of the cryolithozone, Termika pochv i gornykh Spiridonov, V. V., and Semenov, P. P., 1980, Probporodv kholodn.ikh rayonakh [Thermal aspects oflems of environmental protection associated withsoils and rocks in cold regions]: Yakutsk,pipeline construction, in okhrana okruzhayushchcyIM SO AN SSSR, p. 5-14.sredy pri osvoyeni5i obZasti mnogoletnemerzlykhPerl'shtein, G. Z., 1979. Vodno-tepzovaya meliorcrt- porod [Environmental protection associated withsiya merzZykh porod na Severo-Vostoke SSSRthe development of the permafrost zone]: Moscow,(Warming and draining of permafrost materials Nauka, p. 60-66.in the Northeast of the USSR]: Novosibirsk,Stremyakov, A. Ya., Chekhovskiy, A. P., andNauka, 302 p.Pavlunin, V. B., 1980, The impact of urban strue-Polozkov, A. V., Orlov, A. V., and Nikirin, V. 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124[Environmental protection associated with thedevelopment of the permafrost zone]: Moscow,Nauka, p. 67-71,Sukhodrovskiy, V. I?., 1979, Eksogennoye rei: 'yefobrazovaniyev kriolitozone (Exogenic reliefformation in the permafrost zone]: Moscow, Nauka,279 p.Trofimov, V, T., Bodu, Yu. B., and Dubikov, G. I.,1980, Kriogennoye stroyeniye i Z'distost'mnogoZetnemerzZykh prod Zapadno-Sfbirskoy plity[Cryogenic structure and ice content in permafroston the Western Siberian plate]: Moscow,Izdatel'stvo MGU, 245 p.Turbina, M.I., 1980, Changes in natural conditionson a section of operating pipeline (CentralYakutiya) , & Merzlotnye issZedovan-iya v osvaiv-ayemykh rayonakh SSSR [Permafrost investigationsin the developing areas of the USSR]: Novosibirsk,Nauka, p. 31-36.Turbina, M. I., 1982, Evaluation of geocryologicalconditions in the valley of the middle Amga inconnection with agricultural development of thearea (based on the example of the Betyun' area),- in Termika pochv i gornykh porod v kholodnikhrayonakh [Thermal aspects of soils and rocks incold regions]: Yakutsk, IM SO AN SSSR, p. 135-141.Vital', A. D., 1980, Root systems of turf-formingplants and their significance for re-establishinga vegetation cover destroyed by development of anarea, in Okhrana okruzhayushchey sredy p i OSVOYeniionasti mnogoZetnemerzZykh porod [Environmentalprotection associated with the developmentof the permafrost zone]: Moscow, Nauka, p. 128-133,vpemmnoye rukovodstvo po zashchite Landshaftovpri prokZadke gazoprovodov na Kraynem Severe[Interim manual on protection of the landscapeduring the laying of gas pipelines in the FarNorth], 1980: Yakutsk, M SO AN SSSR, 44 p.Zabolotnik, S. I. and Shender, N. I., 1982, Someresults of an annual cycle of soil temperaturemeasurements under natural conditions and wherethe vegetation cover has beeq destroyed on theUpper Zeya Plain, & Term-ika pochv i gornykhporod v kholodnikh ruyonakh [Thermal aspects ofsoils and rocks in cold regions]: Yakutsk, IMSO AN SSSR, p. 50-57.

I_REGULATORY RESPONSIBILITIES IN PERMAFROST ENVIRONMENTS OF AUSKAFROM THE PERSPECTIVE OF A FEDERAL LAND MANAGERC.V. McVee* and J.V. Tileston**U.S.Bureau of Land ManagementAnchorage, Alaska, USAUntil very recently all land and water resourcesin Alaska were owned by the federal government.There was very little local managementand people could, without approval, search out resourcesand proceed to develop what was found withvery little regulation. In 1959, the U.S. Congressbegan a division of land and responsibilitiesbetween the newly created State of Alaska andthe U.S. government. This led to some changes inphilosophy and made developers deal with two Owners.This largely was the situation in 1968 whenthe Prudhoe Bay oil field was discovered and in1972 when the trans-Alaska pipeline was proposed,In 1971, an old ownership situation was solvedwhen Congress settled aboriginal rights claimed byAlaskan natives (Eskimos, Indians, and Aleuts).This settlement resulted in a decision to convertabout 12% of the State of Alaska into private nativeownership. Finally, in 1981, the remainingfederal lands in Alaska were further subdividedamong four major federal landowners. The net effectof these three federal laws was to createshort-term uncertainties as to resource ownershipand, therefore, uncertainty as to regulatory responsibilities.Thus, a resource developer in Alaska musthave specific goals and objectives that are translateddirectly into regulatory requirements forresource development in permafrost environments.This multiple-ownership regulatory approach requiresunusual coordination and is often a causefor delay in project approvals. Special regulationsthat apply in permafrost environments appearonerous but reflect the fact that when surfacedisturbances are not done correctly there is substantialpotential for long-term degradation ofthe permafrost. Federal agencies, on the otherhand, are obligated to assure that the special requirementsare necessary, fair, and uniformly applied.NATIONAL ENVIRONMENTAL POLICY ACTThe National Environmental Policy Act (NEPA)is the basic national charter for protection ofthe environment. It requires federal decisionmakersto use an interdisciplinary approach in theplanning and approval processes and to seek commentsfrom concerned citizens before decisions aremade and before actions are taken. The NEPA ~KOCessis intended to help federal officials make decisionsthat are based on understanding of environmentalconsequences and take actions that protect,restore, and enhance the environment. The*Former State Director, BZM.**Presented by J.V. Tileston.environmental impact assessment is a systematicprocess that formally documents the decision-maker'srationale for the decision taken and the alternativecourses considered. The basic stipulations,terms, and conditions used in the federalregulatory process are direct by-products of theNEPA analysis that focus upon how unwanted effectscan be avoided entirely or at least reduced to anacceptable level.LAND OWNERSHIP IN ALASKA: ITS PRESENT AND FUTURE1959 - Alaska Statehood Act. This act providedfor 103 million acres (42.7 million hectares)of unreserved federal land to be transferredto state ownership. The state has until1994 to complete its selection of the acreage.The 1959 act also granted to the state title toall submerged lands under inland navigable waters.In all, ownership of about 110 million acres (44.5million hectares), exclusive of offshore areas,will transfer to the state.1971 - Alaska Native Claims Settlement Act.As a condition to settling aboriginal rights, Congressprovided that 70 million acres (28.3 millionhectares) of federal land and some state land beset aside from which Alaska natives could select44 million acres (17.8 million hectares) for privateownership. The 1971 act established Alaskanative village corporations to own lands aroundestablished native communities and Alaska nativeregional corporations to own other lands and subsurfaceresources under village corporation lands.1981 - Alaska National Interest ConservationAct. This act placed final parameters on majorfederal land areas in Alaska as follows:76 million acres (30.8 million hectares)in national wildlife refuges to be man--aged by the U.S. Fish and Wildlife Service.52 million acres (21 million hectares)in national parks to be managed by theU.S. National Park Service.68 million acres (17.5 million hectares)in public lands and special managementareas to be managed by the U.S. Bureauof Land Management.23 million acres (9.3 million hectares)in national forests and special managementareas to be managed by the U.S.Forest Service.This 1981 act also established two major provisionsthat require special attention by federalland managers in Alaska. The first requires thefederal land manager to evaluate all proposals touse any federal lands for any significant resrrictionon subsistence uses. The second established125

FIGURE 1 Distribution of federally managed and state and native landsin Alaska.uniform federal transportation evaluation and approvalprocedures.Including about 2.1 million acres of nationaldefense lands, the federal government, principallythe Department of the Interior, will retain directproprietary regulatory responsibility for about59% of Alaska.As of June 1983, some 89 million acres (36million hectares) were under exclusive jurisdictionof the state or Alaska native corporations.For federal lands selected but not conveyed tostate or native entities, there is some form ofmutual cooperation, coordination, or actual sharingof the regulatory responsibilities. Ocvnershipis still fluid. Betueen June and October 1 of1983, an additional 6 million acres (2.4 millionhectares) will be transferred Prom federal tostate or native ownership.Land exchanges between federal, state, andnative ownership also are becoming a prominentfactor in transferring resource ownership to enhanceboth preservation and development opportunities.A major focus of recent exchange proposalshas involved the Alaska Arctic Slope, where developmentof energy resources is the primary use.A practical question of any major resourcedevelopment project in a permafrost environmntis, who Owns the gravel? In Alaska, gravel is a

127subsurface resource; therefore, if on native ea corporation lands, the native regional corporationcwns the gravel. If the gravel source isin a non-navigable waterway, the adjacent landownerowns the gravel; if in a navigable waterway,the state owns the gravel.LAND MANAGEMENT OBJECTIVES AND REGULATORY ACTIONSEach native corporation has its own land manageasentobjectives, and the state also has landmanagement objectives for land under its jurisdiction.Each federal land manager is given specificground rules by the U.S. Congress for resourceprotection and development in Alaska. These rangefrom strict preservation to various form of multiple-useand preservation. For example, the U.S.Bureau of Land Management manages the 23-millionacre(9.3"million-hectare) National Petroleum Reservein Alaska for petroleum extraction. Whilejust north of Fairbanks, Congress had directed theBureau of Land Management to manage the highlymineralized 1-million-acre (0.4-million-hectare)White Mountains National Recreation Area for publicrecreation and the adjacent 1.2-million-acre(0.5-million-hectare) mineralized Steese NationalConservation Area.Each land manager, through its regulatoryfunctions, is fulfilling its obligation to makewise decisions for the benefit of the owners.This is a balancing game where most options areneither good nor bad, but "better" or "worse." Afederal agency's constituencies include 227 millionstockholders or citizens of the U.S., thePresident of the U.S., the Secretary of the Interior,Congress (especially the Alaska delegationand members of the appropriations committees), theGovernor, and all too frequently the federalcourts.The state and native landowners have similarconstituencies to be considered in land-use authorizationin permafrost environments.REGULATORY ACTIVITIES TO PROTECTPERHAFROST ENVIRONMENTSThe degree of federal regulation is usuallycOmmeneurate with the level of the expected activityand its duration, the sensitivity (physicaland political) of the area to be disturbed, andthe public and private interests at risk.Federal regulation can, and does, take placeduring the design, operation, and maintenancestages of resource development at four distinctperiods:Exploration - Locate the resource.Development - Prepare the resource to goto market.- Production - Produce and transport the resourceinto the market.- Shutdown - Economic life of the productionphase is completed.Certain regulations have universal application,while others are specific to the lands managedby a particular owner (federal, state, or native).At the federal level in Alaska, there is astriking degree of similarity to the regulatoryprocess in that Congress fixes the level of resourceuses and determines broad priorities forwhich resource uses come first.Each federal land manager prepares a land-useplan that outlines the criteria for resource usesand protection standards. Each land-use plan undergoesnumerous local, state, and often nationalreviews before it is finally adopted.There is an accelerating trend to place withthe applicant primary responsibility for showingthat there will be no undue or unnecessary harm tothe existing socioeconomic values or to the naturalenvironments as a result of the proposed resourcedevelopment program. In Alaska, these includeinvestigations on subsistence use, endangeredspecies of plants and animala, and culturalresource avoidance as well as the more traditionalpermafrost engineering design questions.In Alaska, federal regulatory actions expressedby stipulations, terms, or conditions inthe land-use authorizations come in three principalcategories:1. Those designed to prevent or mitigatephysical damam to permafrost environments.ples include:Exam-Avoiding sensitive permafrost areas wheremass wasting, major drainage reconfigurationsor untried engineering would be required.Constructing temporary ice roads and iceairfields (natural or man-made) during theexploration phase in lieu of permanentfacilities where thermal erosion is alikely by-product.Requiring either all upland or aquaticgravel extraction sites according to thermalregimes and site restoration capabilities.Requiring gravel or substitute insulationfor work pads, airfields, roads, drillingareas, and housing areas, according to thepermafrost regime and the commitment ofavailable gravel resources for other uses.Permitting surface movement of heavyequipment only when the ground is frozento a minimum depth of 12 in.Using air-cushion or low-ground-pressurevehicles as a laeans to avoid constructionof either temporary or permanent transportationfacilities.Using air-transportable equipment whereeither temporary or permanent roads wouldbe necessary.Installing rip-rap or culverted drainagesto mitigate or avoid thermal erosion.Successfully testing new engineering mthodsbefore surface disturbance starts.Requiring rehabilitation/restoration whenthe surface disturbance activities aresuspended for any significant period or aspart of the shutdown phase.Restricting fuel storage and waste disposalsites and methods.L. Those designed to maintain availabiliQof habitats not physically disturbed. Examplesinclude :- Establishing minimum flight altitudes for

128-a drcraft crossing high-' dens ity waterfowlnesting areas during the nesting season.Avoiding activity near occupied bearsites.Avoiding caribou calving grounds duringthe calving season.* Avoiding major caribou migration routes orrequiring special engineering designsfor mitigation,-Avoiding peregrine falcon nest areas duringthe nesting period.Designing and locating snow-collecting-structures in relation to winter habitatareas used by wildlife.Designing culverts for fish passage.Maintaining natural hydrologic regimsthrough fish spawning areas.Maintaining minimum flows in key overwinterfish habitats.3. Those designed to prevent or mitigatesociocultural and aesthetic disturbance. Theseinclude:Locating facilities away from rural communities.Prohibiting families at construction orremote operatonal facilities.Avoiding local subsistence use areas (fishcamps, hunting camps, traplines, caches,cabins, berry-picking areas, local firewood,or house log areas), especially duringperiods of use.Locating and avoiding cultural and historicplaces.Requiring employment of local workers.Instituting job training to provide skillsneeded by local residents to secure employmentduring the exploration, construction,or operational phases of the proposedproject.Increasing employment opportunities of minoritygroups through minority contracts.Prohibiting hunting by personnel while locatedat remote facilities.Evaluating how the project will look whencompleted (color, form, fit to terrain).Evaluating whether temporary or permanenttransportation facilities will be approvedat the exploration phase.TRANSPORTATION FACILITIESMajor resource developments in Alaska frequentlyrequire construction of new transportationfacilities. While the mine site, timber harvestarea, or oilfield may occupy a relatively smallarea, be in a single ownership, and impact only afew ecosystems, transportation system involvemuch larger areas of impact, cross numerous ownerships,and frequently involve numerous ecosystems.The development and transportation decisionsare usually separate.The transportation system is frequently thefocus of major controversy, as new transportationcreates newresources.development opportunities for otherREGULATORY UNIFORMITYA11 land managers, resource developers, andtheir respective interest groups desire uniformregulatory processes and fair stipulations, terms,and conditions.The problem is, "Whose process?" and "Fair towhom? ''In Alaska, there are several cooperative venturesstarted or now going under the auspices ofthe Alaska Land Use Council, a federal/state/native entity created by Congress under the AlaskaNational Interest Land Conservation Act. Theseventures include:* Standards for wildfire suppression onstate, federal, and native ownerships.A process for conducting subsistenceevaluations.Uniform standards for oil and gas exploration,development, and production onstate and federal lands.Management of federally reserved accesseasements across native ownerships.- Establishment of natural control areasagainst which to measure the effectivenessof permit stipulations.CONCLUSIONSConferences such as this pinpoint currentstate-of-the-art opportunities and outline potentialsolutions being tested. More importantly,they maintain established lines of communicationand open new ones between land managers, researchers,and resource developers.The regulatory process is an expression ofthe concerns landowners have in protecting resourcesentrusted to their care. In the case o€federal agencies, these concerns are required bylaw. Requirements imposed in permafrost areas mayappear particularly onerous, but they reflect thepotential for long-term serious degradation of thepermafrost environment. A principal factor in thedecision process mst be "When in doubt, be conservative. '*Federal agencies, on the other hand, are alsoobligated to assure that requirements placed onindustry are necessary, are fairly and uniformlyadministered, and are reasonable in relation tothe values at risk.Government agencies also have the responsibilityto assure that proposed developments thatcut across land ownership boundaries are evaluatedunder similar criteria. Terms, condltions, orstipulations should be reasonably compatible betweenadjacent landholders. Nothing strains thecredibility of the regulatory process more thanhaving radically different standards on oppositesides of an invisible ownership line.

TERRAIN AND ENVIRONMENTAL PROBLEMS ASSOCIATED WITH EXPLORATORY DRILLING, NORTHERN CANADAH.M. FrenchDepartments of Geography and Geology, University of OttawaOttawa, CanadaRecent environmental concerns in northernCanada relate largely to the search for hydrocarbonsin either the Northern Yukon, the MackenzieValley, the High Arctic islands, or offshore inthe Beaufort Sea. Since the extraction of othernonrenewable mineral resources is still limited inextent (Indian Affairs and Northern Development,1983), this paper restricts itself to land-basedoil and gas exploration activity, and provides examplesfrom the northern interior Yukon.The last 15 years has witnessed a growingawareness of the sensitive ecological nature ofmuch of northern Canada. Unfortunately, some ofthe recently discovered hydrocarbons occur in themore fragile tundra and marine environments whereplant and animal life is relatively abundant andwhere ice-rich permafrost is widespread. A cornerstoneof federal government policy in Canada isthat northern development can only be sanctionedif all possible effort is made to minimize the environmentalimpact of theae activities upon boththe physical environment and the northern indigenouspeoples (Chretien, 1972; Allmand, 1976).One of the more important steps that havebeen taken to promote this general objective wasthe passing of the Territorial Land Use Act andRegulations in 1971. Other initiatives taken includeterrain sensitivity and surficial geologymapping, undertaken primarily by the GeologicalSurvey of Canada in areas of potential economicactivity (e.g. Barnett et al., 1977), preparationof environmental impact statements by industry andtheir assessment by federal government agenciesprior to the granting of permits (e.g. Slaney andCo., 1973; Beak Consultants, 1975), establishmentof government-eponsored commissions of inquiry intothe social and environmental effects of majordevelopment proposals (e.g. Berger, 1977; Lysyk etal., 1977), and support of research into arcticland use problems by the Federal Department ofIndian Affairs and Northern Development (e.g. Kerfoot,1972; Wein et al., 1974; Bliss, 1975; Smith,1977; French, 1978a, 1981).Other papers related to environmental problemsof drilling in northern Canada include thoseby Bliss and Peterson (1973) and French (1978b;1980). Similar studies dealing with northernAlaskan well sites are also available (e.g. Lawsonet al., 1978; Lawson and Brown, 1979; Johnson,1981).GENERAL CONSIDERATIONSTerrain problems in northern Canada frequentlyrelate to the melt of ice-rich permafrost andsubsequent ground instability. Other concerns relateto the geotechnical properties of certain ma-terials, particularly those that are unconsolidatedand susceptible to either natural or man-inducedfailure and mass movement.With respect to oil and gas exploration, someof the early environmental concerns were relatedto seismic and other transportational activities.Recent studies in the Northwest Territories, however,suggest that the impact of modern transportationalactivities has been reduced to a minimum;improvements in industry operating practices (e-g.rhe use of vehicles equipped with low-pressuretires) and the strict application of land use regulations(e-g. restriction of cross-tundra vehiclemovement to winter months) are important factors.Viewed in this light, the potential for the mostserious terrain and environmental damage now isassociated with the drilling operation itself,which often extends into the critical summermonths, and the disposal of waste drilling fluids.Several factors accentuate terrain disturbance problems adjacent to well sites. First, onmany islands there is an absence of easily accessiblegravel aggregate suitable for pad construction.This problem is particularly acute on theSabine Peninsula of eastern Melville Island wherethe Drake and Hecla gas fields are located andwhere there is a near-continuous lichen-moss coveroverlying soft, ice-rich shales of the ChristopherFormation. Wherever possible, urethane matting isplaced around the rip and beneath buildings tocompensate €or any gravel deficiency. Road con-struction is also a problem because of the lack ofaggregate in many Localities. Furthermore, althoughcompacted snow is often used for winterroads elsewhere in northern Canada, the very lowsnowfall of the High Arctic limits this possibility,and strong winds leave many flat areas virtuallysnow-free during the entire winter.A second factor indirectly promoting terraindisturbance is that an increasing number of wellsare being drilled to greater depths as deeper geologicalstructures are tested. Since the timeneeded to drill a hole increases with depth, activityat many arctic well sites often continuesinto the critical summer months when tundra isthawed. The movement of equipment and suppliesaround the site at this time of year can lead toconsiderable terrain disturbance, especially ifthere is a gravel shortage at the site.Environmental problem6 of land-based wellsoften relate to the disposal of waste drillingfluids (French, 1980). These may be toxic in nature.As a consequence, the Territorial Land UseRegulations require that the fluids be buried inbelow-ground sumps or in reserve pits, so thatthey freeze in situ and become permanently containedwithin the permafrost. In itself, the constructionof a sump is a major terrain disturb-129

130ance. In addition, the influx of relatively warmdrilling fluids can lead to significant changes inthe thermal regime of the permafrost adjacent toand beneath the sump (French and Smith, 1980).Moreover, if a well is drilled deeper than anticipated for various technical or geologic reasonsthe sump may be too small to contain the fluidsused. In some other instances, fluids and toxicmaterials have been either spilled on the tundraor allowed to enter water bodies. In recentyears, the deeper drilling associated with manyonshore wells and the larger volumes of drillingmuds required have highlighted waste fluid disposalproblems.A HISTORICAL PERSPECTIVEThe progressive evolution of land use and environmentalmanagement associated with hydrocarbondrilling activity in Canada can be traced historically.Pre-Land Use Regulation operations (i.e.pre-1971) can be compared, in most instances unfa-vorably, to post-1971 operations. In addition,the most recent drilling operations, when comparedto the early post-1971 operations, indicate bothan increase in flexibility on the part of the regulatoryagencies and an increased awareness of environmentaland permafrost-related issues on thepart of the companies involved, resulting in anoverall decrease in environmental and permafrostconcerns. Evidence of this desire to cooperateand wark together was the recent informal agreementbetween Panarctic Oils Ltd. and Land Resourc-es, DIAND, to drill a well without sump a in theHigh Arctic, on Ellef Ringnes Island, in winter1981/&2 as an experimental procedure to documentthe effectiveness of traditional waste-fluid containmentprocedures (i.e. sump use) vis-a-vis surfacedisposal upon the tundra (e-g. Panarctic,1982a,b).These broad trends can be illustrated withreference to a number of abandoned well sites inthe northern Yukon. Each is representative of adifferent stage in the progression of land use andenvironmental management procedures. The northernYukon is an area underlain by widespread diacontinuouspermafrost, and lies within the boreal€orest-shrub tundra vegetation transition (Oswaldand Senyk, 1977; Wiken et al., 1979). Since 1962,over 50 wells have been drilled in the northernYukon, by far the majority on either Eagle Plainor Peel Plateau.Pre-Land Use OperationsTypical of many early well-drilling operationsin the northern Yukon was the Blackstone D-77, drilled in 1962 and 1963 to a depth of 4028 m.It was a two-season operation that commenced inMarch 1962 and finished in January 1963. In allprobability, there was activity around the siteduring the summer of 1962, but the nature of thisactivity ia difficult to ascertain from the wellrecords. It would appear that the well wasdrilled from a pile-supported platform, remnantsof which still exist at the site.The well was located on gently sloping terrainoccurring towards the bottom of a north-southtr endink. tributary valley of the Blackstone River.Poor drainage conditions at this site togetherwith silty ice-rich colluvial sediments produce anopen forest woodland of black spruce (piceamriana) and tamarack (rarix sp.) with a relativelydense shrub layer (dwarf birch, willow, ericaceousshrubs) and sedges (Carex spp.) .During site preparation, in the winter of1961/62, this vegetation had been cleared andprobably burned. Recent ecological and forestsurveys of the northern Yukon now clarify the implicationsof such actions. For example, in themoister environments of the interior Yukon, afire cycle occurs that is slightly different fromthat characteristic of well-drained sites. Accordingto Zoltai and Pettapiece (1973), in moistenvironments, sedges and cottongrass tussocks survivethe fire and thrive in the absence of competitionand because of the increased moisture asso-ciated with the thickening of the active layer.This makes the re-establishment of black spruceand tamarack difficult. The result is the developmentof areas of fire-induced tundra composed oftussocks or tussock-dwarf birch. When re-examinedin 1979, black spruce and tamarack had not succeededin reclaiming the area. Instead, substantialthermokarst had developed within the area ofthe well site. Thermokarst mounds, 1-3 rn inheight, together with deep pools of standingwater, 2-4 m deep in places, surrounded the olddrilling platform. maw depths in the diaturbedterrain commonly exceeded 90 cm while those in adjacentundisturbed terrain were less than 45 cm.Revegetation was in the form of sedges, masses,dwarf birch, and cottongrass.In the general vicinity, seismic lines reveala similar history of physical disturbance andthermokarst. The removal of trees and surface organicmaterial had led to the formation of waterfilledtrenches, 80-100 cm deep, colonized byaquatic plants (Equisetum spp., Carex spp., mosses).In summary, the Blackstone D-77 well site illustrateshow environmental issues were ignoredbefore the introduction of the Territorial LandUse Act and Regulations. The permafrost-vegetationrelationships were little understood and thephysical (1.e. thermokarst) changes that resultedwere long-lasting and permanent. In many ways,these early Yukon well-drilling operations weresimilar to some of the early operations on theAlaskan North Slope (e.g. Lawson et al., 1978).Post-Land Use OperationsOne of the first wells to be drilled on theupland surface of Eagle Plain following the introductionof the Territorial Land Use Regulationswas the Chevron SOBC Wm N. Parkin W61. Not onlywas it drilled completely in the winter of 1971/72, but the site chosen was relatively welldrained and underlain by consolidated bedrock possessinglow ground ice amounts. In contrast tothe Blackstone D-77 well site, therefore, minimalterrain disturbance occurred at this site. Thisreflected (a) the one-season, winter drilling programand (b) the low terrain sensitivity of thesite. The absence of a rigpad probably reflectedthe absence of easily accessible surficial aggre-

131gate and the reluctance of the land use regulatorybodies at that time to extract aggregate fromlocal bedrock sources.Recent OperationsSince the early 1970's, there has been a progressiverefinement in both industry operatingtechniques and the application of the TerritorialLand Use Regulations. This trend is best illustratedby the last well drilled on Eagle Plain.This was the Aquitaine Alder C-33 well, drilledduring the late winter of 1977178.The well was located on a south facing, gentlysloping (2-5') interfluve, several kilometerssouth of the umin Eagle Plain escarpment. Vegetationin the area consists of an open canopy ofblack spruce (Picea mariana) together with a shrublayer of birch (Betula glandulosa), alder (AlnUSsp.), and some Labrador tea. A moss-lichen layerconstitutes a surface organic mat more than 10 cmthick. At the well site the presence of whitespruce (Picea glauca) and charred remnants ofblack spruce indicated a previous burn.During June 1977, geotechnical and terraininvestigations were undertaken by consultants atthe proposed well site location. The depth of thefrost table and active layer temperatures weremeasured at several sites. As was to be expected,the thaw depths bore a close relationship to thevegetation cover and type, and confirmed the importantthermal role that vegetation plays inthese northern boreal forest-shrub tundra environments.Shallow drilling revealed 10-24 cm of organicmaterial overlying about 2.4 m of silty colluvium,which graded into highly weathered andfissile shale bedrock. The upper 2 m of colluvialsediments possessed excess ice amounts of between10-25%, and natural water (ice) contents exceeded20%. Ground ice amounts then progressively decreasedwith increasing depth. The deeper coresretrieved from underlying shale and sandstone bedrockindicated low ground ice content and highstructural cohesiveness of the rock.Following these observations, a land use permitwas issued for the drilling of the well duringthe winter of 1977178. G large gravel pad wasconstructed for the operation, to prevent thaw ofthe ice-rich surficial material. The aggregatewas obtained by crushing sandstone from a borrowpit opened up along the crest of the main EaglePlain escarpment to the north. Although a smallsump was used during drilling, the majority of thewaste fluids were transported to the borrow area,which served as a main sump. The operation was a-typical, therefore, since the main rig sump wasnot at the site itself, During the summer of1978, operations at the site terminated and siterehabilitation was accomplished the following winter.As a result of these procedures, terrain disturbancesadjacent to the rigpad were minimal.Moreover, no signs of thawing of the permafrost,as might be indicated by slumping of the pad, werevisible in July 1979. It was concluded that themethods adopted to prevent thaw were sufficientlyeffective to offset any increase in thaw due tothe removal of trees and the surface vegetationlayer.DISCUSSIONThese three selected case histories illustratethe effectiveness and application of theTerritorial Land Use Regulations in the borealforest-shrub tundra environments of northernYukon.The changes effected by the introduction ofthe Territorial Land Use Regulations In minimizingdisturbance are clearly apparent. The relativesophistication of the Aquitaine C-33 operation,where a large gravel pad was constructed and activitywas limited to the winter months, can becompared to the earlier Blackstone E77 well sitewhere typical man-induced thennokarat occurredfollowing land clearance and drilling activity inthe summer in an ice-rich locality. Observationsat the Blackstone site suggest that over the longterm (1.e. 15-25 years) natural recolonization,similar to the changes following fire, is as successfulas artificial seeding in site rehabilitation.The containment of waste drilling liquids inbelow-ground sumps has been a standard operatingcondition for wells drilled under the TerritorialLand Use Regulations in both the N.W.T. and theYukon. Equally, it has been one of the conditionsthat has presented the most problems. The AquitaineAlder C-33 Illustrates how an innovativewaste disposal program was undertaken and is representativeof an increased awareness of the needfor flexibility in the application of the TerritorialLand Use Act and Regulations, especially asthey pertain to the disposal of waste fluids. Alternatedisposal methods are actively being investigated,including surface disposal, detoxificationprocedures, trucking to designated disposalsites, and dilution in surface water bodies. Thesurface disposal experiment on Ellef Rlngnes Islandin the High Arctic (Panarctic, 1982a, b) isthe most recent approach, However, the variabilityof local terrain conditions in northern Canadaand the Inherent uncertainty involved in explorationdrilling continues to prevent any one Wastedisposal procedure from being adopted in preferenceto others.CONCLUSIONSThere appears to be no easy solution to theterrain and environmental problems of oil explorationin northern Canada. However, the continuedapplication of the Territorial Land Use Act andRegulations, together with the positive attitudesincreasingly adopted by the operators themselves,are leading to fewer problems that cannot eitherbe resolved or minimized. In the boreal forestshrubtundra environments of northern Yukon, terraindisturbances associated with well drilling inrecent years have been minimized. Where there isa lack of ice-rich surficial deposits, the relativerapidity of natural revegetation is importantin reducing terrain damage. In spite of this,terrain disturbance and sump-related problem dostill occur in other localities in northern Canada,especially north of treeline in the ecologicallymore delicate tundra and polar, semi-desertenvironments. They emphasize the desirability ofsite-specific solutions to minimize impact and a

132thorough understanding of permafrost-vegetationrelationships, in addition to the impositiongeneral land use operating conditions.REFERENCESAllmand, W., 1976, Guidelines for scientific activitiesin northern Canada, Advisory Committeefor Northern Development, Department ofIndian Affairs and Northern Development: Ottawa,Ministry of Supply and Services, CatalogueNo. L 2-47/1976.Barnett, D.M., Edlund, S.A., Dredge, L.A., 1977,Terrain characterization and evaluation: Anexample from Eastern Melville Island: GeologicalSurvey of Canada, Paper 76-23.Beak Consultants Ltd., 1975, Banks Island development,environmental considerations: 1974 researchstudies, Consultants report prepared€or Panarctic Oils Ltd., Calgary, and Elf OilExploration and Production Ltd., Calgary.Bliss, L.C., 1975, Plant and surface responses toenvironmental conditions In the western HighArctic, ALUR 74-75-73: Ottawa, Department ofIndian Affairs and Northern Development,Bliss, L.C. and Peterson, E.B., 1973, The ecologicalimpact of northern petroleum development,& Arctic Oil and Gas: Problems andPossibilities; Proceedings of the 5th InternationalCongress, Fondation Francaised'Etudes Nordiques, Le Havre. p. 1-26.Berger, T.W., 1977, Northern frontier, northernhomeland: Report of the Mackenzie ValleyPipeline Inquiry: Ottawa, Ministry of Supplyand Services.Chretien, J,, 1972, Northern Canada in the ~O'S,Report to the Standing Committee on IndianAffairs and Northern Development: Ottawa.French, H.M., 1978a, Sump studies I: Terrain disturbances,Environmental Studies No. 6:Ottawa, Department of Indian Affairs andNorthern Development.French, H.M., 1978b, Terrain and environmentalproblem of Canadian Arctic oil and gas exploration:Musk-ox, V. 21, p. 11-17.French, H.M., 1980, Terrain, land use and wastedrilling fluid disposal problems, ArcticCanada: Arctic, V. 33, p. 794-806.French, H.M., 1981, Sump studies IV. Terrain disturbancesadjacent to exploratory well sites,northern Yukon Territory, EnvironmentalStudies, No. 19: Ottawa, Department of IndianAffairs and Northern Development.French, H.M. and Smith, M.W., 1980, Geothermaldisturbances in permafrost adjacent to Arcticoil and gas well sites, Environmental StudiesNo. 14: Ottawa, Department of Indian Affairsand Northern Development.Indian Affairs and Northern Developroent, 1983,Canada's North: The Reference Manual, CatalogNo. R71-31/1983E: Ottawa, Ministry ofSupply and Services, p. 8.1-8.19.ofJohnson, L.A., 1981, Revegetation and selectedterrain disturbances along the trans-Alaskapipeline, 1975-1978: Hanover, N.H., U.S.Army Cold Regions Research and EngineeringLaboratory, CRREL Report 81-12.Kerfoot, LE., 1972, Tundra disturbance studies inthe Western Canadian Arctic, ALUR 71-72-11:Ottawa, Departlnent of Indian Affairs andNorthern Development.Lawson, D.E. and Brown, J., 1979, Human-inducedthermokarst at old drill sites in northernAlaska: Northern Engineer, V. lo, p. 16-23.Lawson, D.E., Brown, J., Everett, K.R., Johnson,A.W., Komarkova, V., Murray, B.M., Murray,D.F., and Webber, P.J., 1978, Tundra disturbanceand recovery following the 1949 exploratorydrilling, Fish Creek, Northern Alaska:Hanover, N.H., U.S. Army Cold Regions Researchand Engineering Laboratory, CRREL Report78-28.Lysyk, K.M. , Bohmer, E.M., and Phelps, W.L., 1977,Alaska Highway Pipeline Enquiry: Ottawa,Ministry of Supply and Services.Oswald, E.T. and Senyk, J.P., 1977, Ecoregions ofthe Yukon Territory: Canadian Forestry Service,Environment Canada Publication BC-X-164.Panarctic Oils Limited, 1982a, Surface disposalexperiment of waste drilling fluids, HoodooN-52 well, Ellef Ringnes Island, N.W.T., InitialReport, Phase One, Consultants Report:Calgary, Albert a.Panarctic Oils Limited, 1982b, Surface disposalexperiment of waste drilling fluids, HoodooN-52 well, Ellef Ringnes Island, N.W.T.,Phase Two Report, Consultants Report: Calgary,Alberta.Slaney, F.F. and Company Ltd., 1973, Environnentalimpact assessment study, Melville Island,N.W.T., Consultants Report: Calgary, PanarcticOils Ltd.Smith, M.W., 1977, Computer simulation of microclimaticand ground thermal regimes: Test resultsand program description, ALUR 75-76-72:Ottawa, Department of Indian Affairs andNorthern Development.Wein, R.W., Sylvester, T.W., and Weber, M.G. ,1975, VegetaKiOn recovery in Arctic tundraand forest tundra after fire, ALUR Report 74-75-62: Ottawa, Department of Indian Affairsand Northern Development.Wiken, E.B., Welch, D.M., fronside, G., and Taylor,D.G., 1979, Ecological land survey of thenorthern Yukon, Ecological Land ClassificationSeries: Lands Directorate, EnvironmentCanada, no. 7, p. 361-372.Zoltai, S.C. and Pettapiece, W.W., 1973, Terrain,vegetation and permafrost relationships inthe northern part of the Mackenzie Valley andNorthern Yukon: Environmental-Social ProgramNorthern Pipelines, Task Force on NorthernOil Development, Report 73-4.

PETROLEUM EXPLORATION AND PROTECTION OF THE ENVIRONMENT ON THE NATIONAL PETROLEUM RESERVE IN ALASKAM.C.BrewerU .S. Geological SurveyAnchorage, Alaska, USAThe National Petroleum Reserve in Alaska(NFRA) comprises almost 96,000 km2 of the tundracoveredarea of the North Slope. Its northernboundary is the Arctic Ocean, including almostequal portions of the coastline of both the Chukchiand the Beaufort Seas. A little more thanone-half of its southern boundary follows the divideof the Brooks Range.Except beneath a portion of Teshekpuk Lake,which is approximately 810 km2 in area, the entireReserve is underlain by permafrost ranging inthickness, to the best of our present knowledge,from about 200 to 400 m. The minimum temperatureof the permafrost, below the depth (20 m) of measurableannual change (O.Ol"C), is -10.7'C. Thethickness of the active layer, depending on thesoil material, topography, location within the reserve,and vegetative cover, ranges from 0.3 to1.5 m. The annual precipitation averages about0.3 m and almost 80% of that occurs in the form ofsnow. Thus, the area has been termed a polar desert,in spite of the myriad of generally shallowlakes (1 to 3 m) that are found within the coastalplain area. Most of the Reserve, except near themountain front, is almost devoid of gravel thatcould be used for construction, although approximately13,000 h2 of the area is covered by mostlystabilized sand dunes.Exploration of the Reserve for oil and gaspotential generally has been concentrated intothree time frames. The first was a geological reconnaissanceduring the period 1923-1926 by personnelfrom the U.S. Geological Survey. This wasfollowed by the Navy's exploration program, involvinggeologic mapping, geophysical prospecting,and the exploratory drilling of 36 generally shallowtest wells and 44 core test wells from 1944 to1953 (Reed, 1958). The most recent explorationsoccurred during the period 1974-1981, when firstthe Navy and then the U.S. Geological Survey accomplished21,800 km of reflection seismic surveyand drilled 28 exploratory and 10 developmentwells, the latter in the small, shallow naturalgas fields near Barrow (Schindler, 1983a). Two ofthe exploratory wells were the deepest everdrilled in Alaska, approximately 6200 m deep.The Navy's 1944-1953 exploration program beganunder wartime conditions and even used somemilitary-type equipment, such as tracked landingvehicles €or transporting men and equipment acrossthe tundra. It was a pioneering effort in whichone of the goals was to see what equipment wouldwork in the rigorous arctic environment and whatmodifications might be required in exploratorytechniques. The most important finding of thelatter was the knowledge that overland travelcould only be successfully accomplished during thewinter. The environmental protection ethic wasnot emphasized in those days, nor was research faradvanced concerning the impact of this type op- oferation on the arctic environment. In retrospect,there were two serious environmental results. Thefirst involved overland transportation, especiallyduring the summer periods when, fn order to obtaintraction and to keep from Mgh-centering vehicles,the active layer was bladed down to permafrost.In some instances this resulted in erosion;in all cases it left ditches across the tundrathat are expected to be visible longer thanthe old Roman roads in Britain. The second majorenvironmental impact was that debris, especiallyempty fuel drums, was scattered across the tundra.The latter has been largely rectified, the debrisgathered up and burned or buried, but at a verylarge financial cost (Schindler, 1983b).One very positive.result of that earlier explorationwas that, in 1947, the Navy introduced aprogram of research in arctic environmental. marters,including operating techniques in that environment.The research program continued at theNaval Arctic Research Laboratory at Barrow, sothat by the time oil was discovered at PrudhoeBay, in 1968, an impressive amount of knowledgehad been accumulated (Reed and Ronhovde, 1971).This included information regarding casing collapsein wells; knowledge of the thicknesses ofgravel required along the Arctic Coast to bringthe frost line up into the gravel fill and thusprevent deterioration of the underlying permafrostin all-season roads and airstrips; building designsto fit the environment; parameters concerningfresh ice and sea ice; and a far greater appreciationof the physical and biological parametersto be found in the Arctic.The oil development program at Prudhoe Baygenerally has been cited as a model for accomplishinga task, where a decision has been made,in an environmentally acceptable manner. As a result,during the past few years whenever a programwas projected for the Arctic, there has been atendency for both engineers and many environrnentaliststo want to use methods and parametersshown to work at Prudhoe and to leave a neat andtidy appearance. The former has environmental advantages,but it also has many environmental disadvantagesfor an oil and gas exploration program.Prudhoe Bay is a development complex with anestablished transporation system. The roads,pads, airstrips, and other facilities are permanent,at least for 40 to 50 years. However, in anoil and gas exploration program, one does not wantpermanence, at least until after a discovery ismade. Impermanence not only provides greater environmentalprotection, but it is less expensive.In an exploration program, one wants to "tip-toe''into an area, run the seismic surveys, drill any133

134exploratory wells deemed desirable, and then carefullymove out, leaving no tracks or other evidenceof the activity.The Navy/U.S. Geological Survey explorationprogram during 1974-1981 tried to follow the approachof leaving as little evidence of their exploratoryactivities as possible. All seismicsurveys were run during the winter-spring periodwhen the snow cover was greatest, when overlandtransportation would be most efficient, and whenthe least numbers and species of wildlife werepresent. Exploratory drilling was confined to thewinter sea-son, except where wells deeper thanabout 3500 m were involved. Beyond that depth,the operation was faced with the trade-offs betweenthe environmental and cost impacts of constructingall-season roads and airstrips and theenvironmental and cost impacts of operating overseveral winters as well as the risk of not completinga well when work had been suspended severaltimes.Lake ice was used for aircraft landing surfaceswherever possible. In two instances, air-strips 1600 m long to accommodate Hercules C-130aircraft were constructed directly over a flattundra expanse. In one of those instances theairstrip was constructed in the same location thefollowing year. Even after the second season, itwas extremely difficult to find any evidence ofthe 30-cm-thick airstrips constructed on the tundra.In the case of three deep wells, highstrengthinsulation was used in airstrips in orderto reduce the thickness of gravel required tobring the frost line into the base of the fill.Ice roads were constructed wherever heavytraffic, such as 201n3 dump trucks, might be makingrepeated trips. These were built to a minimumthickness of 15 cm before heavy traffic was allowed.The longest ice road constructed was 60km. Water was applied daily to keep a smooth runningsurface, but by the time 85,000 m3 of gravelhad been hauled over the road, at speeds of up to80 km per hour, the ice road had an average thicknessof about 45 cm. Almost no damage, not even a"green" trail or trail discernible from a low-flyinghelicopter, was evident the following summer.Snow roads, per se, were not constructed becauseof the generally insufficient amount of snowavailable and because whenever snow is used itmust be scraped up. This requires blading withtractor-type equipment and, no matter how carefulthe operator is, considerable tundra damage usuallyensues.While 1.5- to 1.7-m-thick gravel drillingpads will bring the frost line into the base ofthe pads along the coast of northern Alaska, a padof that thickness will be quite visible in thelong term, will be well-drained, and will be difficultto revegetate because of a lack of adequatesoil moisture. A thick pad, however, is not necessaryto support a winter-only drilling operation.A thin pad, 0.5 m thick, frozen during thewinter months, satisfactorily supports a winter-only drilling operation; it requires no added materialto be hauled to the site since sufficientmaterial is available after digging a reserve(mud) pit; it retains sufficient moisture to en-able grasses to become established, thus is easierto revegetate; and it rapidly recedes into the underlyinglandscape. These thin pads were used onthe NPRA during the latter portion of the explorationprogram and proved to be more satisfactorythan the thick pads from both the engineering andenvironmental standpoints. They eliminated theneed to open material sites, and thus the need forhauling heavy loads of gravel and of rehabilitatingmaterial sites. In addition, they were economicalto prepare.The recent exploration program on the NPRAreceived few complaints from environmental groups,and since its completion it has occasionally beencited by such groups as the model way to accomplishan exploratory program in the Arctic. Theprogram also was completed approximately 12% underits budgeted funding.REFERENCESReed, J.C., 1958, Exploration of the Naval PetroleumReserve No. 4 and adjacent areas, 1944-1953, Part 1, History of the exploration:U.S. Geological Survey Professional Paper No.301.Reed, J.C., and Ronhovde, A.G., 1971, Arctic Laboratory:Washington, D.C., Arctic Instituteof North America.Schindler, J.F., 1983a. The second exploration,1975-1982, National Petroleum Reserve inAlaska (formerly.Nava1 Petroleum Reserve No.4): Anchorage, Alaska, Husky Oil NPR Operations,Inc.Schindler, J.F., 1983b. Solid waste disposal - NationalPetroleum Reserve in Alaska, g Proceedingsof the Fourth International Conferenceon Permafrosr, Fairbanks: Washington,D.C., National Academy of Sciences, p. 1111-1116.

TERRAIN SENSITIVITY AND RECOVERY fN ARCTIC REGIONSP. J. WebberInstitute of Arctic and Alpine Research, UniversityBoulder, Colorado, USAof ColoradoThe protection of vegetation, and its sensitivityto and recovery from various impacts, suchas surface damage, oil spills, and dredge-and-fillactivtties, have been under investigation on thetundra of the Alaskan Arctic Slope for the past 15years. Much of what I will discuss applies tosimilar permafrost terrain, both in Alaska andelsewhere.There seem to be two generic problems or difficultiesconcerning the protection of tundra andthe necessary development of its resources:The first problem is the complexity ofland ownership, permitting, and regulatorymatters.* The second problem is the lack of knowledgeof ecosystem dynamics and variability.The first problem has been discussed by severalof the previous speakers and I will confinemy remarks to the second problem.Lack of knowledge and Understanding of theecosystem is due in part to the vastness of theregion under consideration, its large variability,and the complexity of its systems. Permafrost regionsvary from polar and alpine deserts throughtundra to forests. Their holistic and complex natureis well illustrated by the many effects triggeredby seemingly simple events, such as compressionof the tundra vegetation mat. This variabilityand complexity make generalizations difficult,and predictive capabilities are poor. At present,the problems are best analyzed and treated by examiningeach case of potential or actual impact inits specific site context. It is to be hoped thatwith increased knowledge, prediction based on establishedprinciples will be possible.Our lack of understanding also rises from semanticconfusions in the use and definitions ofterms. There are at least three causes for thesemantic problem associated with the protectionof permafrost terrain. The first is careless useof terms and terminology. The second is the interdisciplinarynature of environmental protection,and the third is the language difficultiesassociated with this International concern.The semantic confusion inhibits the acquisitionof new knowledge. It serves to reduce communicationamong the various interest groups, sucha$ developers and environmentalists, since theymay use term in different ways. A few examplesof semantic problems will suffice to illustratethe prospects for confusion:* The use of the term "fragile" for tundravegetation can be misleading. While sometundra is fragile and easily disturbed,the majority of it, in my opinion, is reasonablyrobust. Of course, "robustness"is another term that would need defining!The concept of tundra fragility relatesmore to its slowness to recover ratherthan its ease of disruption or breakage.If we are to use the term "fragile,"then It must be done with more preclsion.The use of the terms "resistance" and"resilience" of ecosystems to stress isanother example of the confusion fromsemantic problems. These are two verydifferent notions. "Resistance" variouslyeans the robustness of the vegetationor system to disruption or theease with which it returns to its formrstate after disruption, and "resilience"is a better term for recovery from disturbance.One final term that causes confusion isthe term and idea of "cumulative impact."This idea is an easy one to envisage--justas is fragility--but aworking concept of "cumulative impact"is not readily available: there is notheory of "cumulative impact." Sincethe notion is Incorporated In the U.S.legislation to protect wetlands fromdredge-and-fill activities, it requiresclear, uniform understanding. This isan area in need of future research.Until we exercise care with our use of termsand reduce semantic conflicts, our progress towardacceptable practices to regulate activities. minimizeimpacts, and enhance recovery is likely to beimpeded or confused. I should like to make a pleafor someone to make a thorough review of appropriateterm and terminology with recommendations forappropriate use in the protection of permafrostterrain. Until this is done, however, we rmst defineour terms with each usage or refer to similarusage in the relevant literature.A further concern in this area of definitionsis that of landform, soil, and vegetation classification.'There is a remarkable lack of rigor indoing this, which can only lead to misinformationor miscommunication.Adequate protection and management of permafrostterrain requires good terrain description,adequate mapping, and inventory of the lands beingaffected. Adequate large-scale mapping (1:6000)will help in the planning, locating, permitting,and construction design of various structures.The North Slope Borough, the principal Local governmentof the Alaska Arctic Slope, is encouragingthe mapping and inventory of its lands. The NorthSlope Borough is currently mapping, at a varietyof scales, the geology, soils, terrain, and vegetationof its lands. The data from this largeproject are being incorporated into an automated,135

136computer-retrievable, ;eoRraphi c-based informationsystem. This systekwill-be-of great value in thepermitting process, for the researcher, the developer,and the landowner, Similar efforts havebeen undertaken by several organics and petroleumcompanies in the Prudhoe Bay region and the ArcticNational Wildlife Refuge (Walker et al., 1980,1982).Our lack of knowledge can be remedied by morebasic applied research and more discussion amongspecialists. This will, I believe, better enableus to protect cold-dominated ecosystems, but itrequires time, funds, and people. Perhaps, ofthese three requirements, time is the most important.Time is also at a premium in the process ofpermitting specific activities. Thus, we see aconflict between the researcher who needs motetime to document a potential impact and the developerand consumer who does not want to wait forthese conclusions or to find ways to mitigatethem. Clearly, the solution is a compromise, andboth development and research need to be accomplishedsimultaneously. However, development thatwould potentially leave impacts should not proceedwithout adequate concurrent research or equivalentmitigative actions.Research priorities to increase our understandingappear to fall into two related categories(see for example National Academy Press, 1983)- The first priority is to establish sitesfor long-term studies of man-made and naturalchanges, to include changes in atmosphericcarbon dioxide, permafrost temperature,and biological communities.* The second research priority is to betterdocument and monitor case histories of impactsand recovery from damage. This includesthe development of better methodsof measurement and prediction of impactsand recovery from damage.Finally, the continuing development of permafrostlands can be done in a fashion compatiblewith preserving their biological wealth and heritage.Construction and maintenance costs to provideenvironmental protection may at times be consideredexcessive. Development and protection canbe achieved through a better knowledge of the naturalscience of these systems and appropriateplanning as evaluated in the introduction to thepanel report. Such knowledge, once gained, shouldbe exchanged freely.REFERENCESNational Academy Press, 1983, Permafrost Research:An Assessment of Future Needs: Washington,D. C.Walker, D.A., Everett, K.R., Webber, P.J., andBrown, J,, 1980, Geobotanical atlas of thePrudhoe Bay region, Alaska: Hanover, N.H.,U.S. Army Cold Regions Research and EngineeringLaboratory, CRREL Report 80-14.Walker, LA., Acevedo, W., Everett, K.R., Gaydos,I,., and Brown, J., 1982, Landsat-assisted environmentalmapping in the Arctic NationalWildlife Refuge. Alaska: Hanover, N.H., U.S.Army Cold Regions Research and EngineeringLaboratory, CRREL Report 82-37.

Climate Change and Geothermal RegimePANEL MEMBERSCheng Guodong, Institute of Glaciology and Cryopedology, Academia Sinica, Lanzhou, PRCThomas E. Osterkamp, Geophysical Institute, Fairbanks, Alaska, USAMichael Smith, Department of Geography, Carleton University, Ottawa, CanadaJames Gray, Department of Geography, University of Montreal, CanadaINTRODUCTIONA. Judge and J. PilonThe energy crisis in 1973 emphasized the needto find and develop arctic hydrocarbon reserves.A similar need for other mineral resources willdevelop in the next few decades. Exploitation ofthese resources and the associated infrastructuresof buildings and transportation facilities willoccur on and in permafrost, which underlies 24% ofthe land area of the globe. Much of the near-surfacepermafrost contains massive ice. Numerousreports and papers have docurented the immediateimpact of development through clearing vegetation,interrupting drainage, and operating hot oil andchilled gas pipelines. A 2-m-diameter pipelineburied in permafrost, for example, will thaw to 9m in 5 years. Mean air temperature changes ofseveral degrees can be expected to occur over thelifetime of such projects, with possible long-termregional effects on the terrain traversed by apipeline or highway as important as the short-termlocalized impact of the development itself.Knowledge or prediction of such climate trends becowsa critical aspect of design for long-termperformance.The regional distribution of permafrost is afunction of climate, although wide variations inground thermal conditions do occur in small areasof uniform climate due to site-speciric conditions.Where mean annual ground temperatures areclose to O'C, specific local factors can determinewhether or not permafrost is present. Changes inthe ground thermal regime, and hence in the distributionand thickness of permafrost, can resultfrom changes in both climate and local conditions.The specific effects on permafrost of a macroscaleclimate change are not necessarily simple,depending on the complex interaction of climate,microclimate, surface, and ground thermal conditions.If, €or example, a global warming, concentratedin the high latitudes, results from increasingCOP levels, the effect will certainly beprofound. Several recent papers report on thepossible consequences of increased temperature andchanges in precipitation on permafrost conditionsin Alaska (Goodwin et al., 1984; Osterkamp, 1984),Assuming that a rise in mean annual air temperatureis translated directly into a similar increasein mean annual ground temperature, permafrostat the southern limit may retreat northwardsby as much as 100 km per degree warming. This hasbeen observed in Manitoba where over the past 200years the areal extent of permafrost has diminishedfrom 60 to 15%. With the discontinuous per-=frost a thicker active layer will develop, widespreadthaw settlement in areas of massive icewill occur, south-facing slopes will become permafrost-free,and surface and groundwater patternswill change. Extensive thermokarst features willform from the thaw of massive ice leading to theformation of lakes, new drainage patterns, alasareas, etc. Slopes in general will become lessstable, leading to extensive failures and erosion.Rivers less confined by frozen banks will changecourse and carry increased sediment loads. Coastalareas could well be inundated by the sea as thethaw settlement lowers elevations to below sealevel, especially if a general rise in sea leveloccurs.ment ofThe impact of differential thaw settleasmch as a meter on construction such asroads, pipelines, and buildings is not difficult137

138to visualize. In the continuous permafrost zone,the southern boundary of which will also movenorthward, ground temperature will also rise,leading to some thawing and related settlementproblems. Most of the immediate impact of warmingand thawing will occur close to the ground surfacewhere human activities are most dramatically affected.A decrease in air and ground temperature willlead to a reversal of the above features, includinga southerly advance of the discontinuous andcontinuous boundaries of permafrost and correspondingvegetation zones. More importantly itwill lead to the growth of massive ice bodies, areactivation of the growth of ice wedges in moresoutherly areas, and a general thickening of permafrostand consequent changes in surface morphologyand drainage patterns (see Osterkaq, 1984,and Brown and Andrews, 1982, for additional discussion).Climatic fluctuations seem to be reflected inpermafrost behavior, for example the northward retreatof the southern permafrost boundary, the initiationof extensive thermokarsting in the southernMackenzie Valley in the past hundred years,and within the last decade, the reactivation ofice wedges on the arctic coast.In general, direct observational measurementof climatic change in the Arctic is limited, soproxy methods such as palynology, oxygen isotopedistribution, and geothermal analysis become importantways of extending the record of the past.Geothermal analysis does offer a direct, if resolution-limited,method of examining past changesin mean ground temperature.Brown and Andrews (1982) have summarized thetrends from many arctic series of proxy informationas follows:A long-term cooling trend of the order of0.7OC per thousand years.Superimposed on the long-term trend, a-series of major oscillations with wavelengthsof 500 to 600 yr.Evidence from the eastern Canadian Arcticthat summer temperatures fell below themean of the past 6000 years between 2500and 1500 years ago and did not riseabove the mean until the last 100 years.Temperatures in the 20th century that are,on average, as warm as they have been forseveral hundred years, if not thousands ofyears.The last point may be an exaggeration, althoughcertainly no warmer periods have occurredsince the 11th century. Whether or not the generaltrends will continue or whether the impact ofCop in the atmosphere will reverse such trends remainsa point of considerable debate.Aside from the problems of interpreting thestrongly attenuated events in the distant past,geothermal analysis of more recent climatic eventshas had notable success. In temperature logsthroughout eastern North America, the MackenzieValley, and the arctic coastal plain, the evidencefor a general warming trend starting a century agofollowed by a recent downturn agrees well with meteorologicaldata. In general, the evidence indi-cates that ground temperatures increased morethan air temperatures. A detailed study in theuniform shield rocks of northern Ontario revealedperturbations caused by surface ground temperaturesincreasing by 1.5'C in the Little ClimateOptimum from 1000 to 1200 A.D. and decreasing by1°C during the Little Ice Age from 1500 to 1700A. D.One of the serious problems with using geothermalanalysis as a proxy technique arises fromthe non-uniqueness of the solutions. Given a seriesof dates at which climate change occurred fromother sources, the techniques will successfullyresolve amplitudes of the change for up to aboutfour events. Improved continuous or semicontinu-01.18 logging lnethods may eventually improve uponthis. In summary, the present strengths and usesof this type of analysis of borehole temperaturesare probably as follows:Given good meteorological inforlaation onclimate change over the past 100 years, todetermine how that change has been translatedinto ground temperature. Theanalysis will enable some prediction ofhow future trends will affect permafrost.In areas where laeteorological data arenon-existent or of short duration, to determinethe long-term fluctuations ofground temperature over the past severalcenturies. Some answers will be derivedas to whether areas such as the High Arcticfollow global trends.Given proxy information on the dates andduration of climatic events, some ideas of-amplitude can be derived from geothermalanalysis.Promising areas of application to more remoteclimate events, including the derivationof ice-base conditions during Wisconsinglaciation, require further refinement.REFERENCESBrown, J. and Andrews, J.T., 1982, Influence ofshort-term climate fluctuations on permafrostterrain, & Carbon Dioxide Effects Researchand Assessment Program, Environmental and SocietalConsequences of Possible C02-InducedClimatic Changes, DOE/EV/10019-02, V. 2, pt.3: Washington, D.C., U. S. Department of Energy.Goodwin, C.W., Brown, J. and Outcalt, S.I., 1984,Potential responses of permafrost to climaticwarming, & Proceedings of a Conference onthe Potential Effects of Carbon Dioxide-InducedClimatic Changes in Alaska (J.H. Mc-Beath, ed.): Fairbanks, University of Alaska,Mac. Pub. 83-1, p. 92-105.Osterkamp, T.E., 1984, Potential impact of a warmerclimate on permafrost in Alaska, & Proceedingsof a Conference on the Potential Effectsof Carbon Dioxide-Induced ClimaticChanges in Alaska (J.H. McBeath, ed.): Fairbanks,University of Alaska, Misc. Pub. 83-1,p. 106-113.

STUDY OF CLIMATE CHANGE IN THE PERMAFROST REGXONS OF CHINA - A REVIEWCheng GuodongInstitute of Glaciology and Cryopedology, Academia SinicaLanzhou, People's Rebulic of ChinaLATE PLEISTOCENE STAGEIn China, there are no reports of double-layered permafrost or the typical ice wedge casts.The depth of the measured ground temperature inpermafrost regions is less than 200 m. Therefore,most of the environmental reconstructions in geocryologydepend on relict periglacial features,especially involutions and soil wedges.Qlnghai-Xizang PlateauCui (1980a) has suggested that the lower limitsof permafrost on the Qinghai-Xizang Plateau inthe Late Pleistocene are indicated by the widespreadinvolutions on the second terrace (3900 m)of the Pingchu River at Xigaze in the south andthe involutions on the second terrace (3600 m) atNaij Tal in the north (Fig. 1). The mean annualair temperature at Naij Tal is about -0.6"C at8ooo 1Lower limit of permafrost:present, and the mean annual air temperature atthe lower limit of the existing permafrost on theplateau 16 from -2 to -3°C. Accepting that themountains have lifted 600-900 m since the end ofthe Late Pleistocene, it has been deduced thatthere was a probable temperature depression of 5-6'C on the plateau during the Late Pleistocene.But Pu et al. (1982) argued that the lower limitof permafrost during the Late Pleistocene reachedthe latitude of 30'N and an altitude of 4200 m inthe south, along the Qinghai-Xizang Highway, butwas lower than 3600 m in the north.Polygons and soil wedges in correspondingprofiles have been found in large quantities onthe Qinghai-Xizang Plateau. Most of the soilwedges are located on the second terrace of rivers.Carbon-14 dating of the material at the bottomof a sol1 wedge located on the second terraceof Zuomaokong Qu, on the northern slope of Fenghuoshan,gives 23,500 * 1200 years B.P. The roean----- Contemporary A-.. I . .-.. -I Postgraclatlon I\hE- 60004 I IE:0.C400036" N 33' N 28' NKunlun Shan Tanggula Shan Himalaya ShanGY Involution * PolygonPingoA SolifluctionFIGURE 1 Lower limits of permfrost at various ages along Qinghai-Xizang Highway (after Cui, 1980).139

140annual air temperature there today is about -5OC. the last ala ciation in northe ast China (Fig. 1).Assuming that an air temperature of -8'C is neces- This lid; roughly coincides with the present daysary for the formation of soil wedges in coarse- 7-8'C isotherm of mean annual air temperature. Itgrained soils, and again accepting that the moun- is deduced that the temperature depression duringtains have uplifted 600-900 m since the end of the the last glaciation in northeast China was alsoLate Pleistocene, it is inferred that the tempera- 7-8'C. Cui and Xie (1982) suggested that at thatture was 6-8°C lower when the soil wedge wastime the southern limit of permafrost in Eastformed than at present. This temperature approxi- China reached to 39'W-40°N, and the southern limitmates the temperature inferred from the lower lim- of continuous permafrost was located at 45'N, butit of permafrost, based on the involutions, andPu et al. (1982) stated that the southern permaalsocoincides with the conclusion inferred fromfrost boundary reached to 34'N. It is questlonthepaleontologic evidence (carbon-14 dating) at able to use involutions alone to indicate perma-23,100 f 850 years B.P. on the north slope of gin frost, until their origin is better known. CuiLing (Shi et al., 1979), that the temperature was (1980b) has proposed that, to be an indicator of8'C lower during the Last glaciation. Zhang permafrost, an involution must show the following(1979) argued Khat the wedge is an ice wedge, and characteristics: (a) the disturbed layer consiststhat the temperature for the formation of the ice mainly of sand or sand with gravel; (b) there is awedge cast ought to be -12'C. clear boundary between a disturbed layer and anunderlying horizontal layer; and (c) the "fold" isNortheast China symmetrical and to extends a certaindistance.There are also many problems of distinguishing iceBased on the southern limits of both the soil wedge casts from soil wedges; the temperature rewedgesand the involutions, Guo and Li (1981) have quired for the growth of soil wedges must be deoutlinedthe southern limit of permafrost during termined by further investigations.TABLE 1 Comparison of climatic changes during postglaciation between Europe and East China.Europe East China*TemperatureYearsDate Stage Period Period fluctuation ("2000- A.D.- -0- B.C.Sub-AtlanticLittleAge Ice -1 0-500Pu Lan Dian -little climate +1 - +2optimum 1400 2000"Zhou Han -1Neoglaciation 3000 - --- 2000--- 4000-PostGlacialSub borealAtlantic4000-Yang Shao +2 - +3 -6000--- 6000--- 8000-"1 0,000-"1 2,000---1 4,000LateGlacialFullGlacialBoreal Hypsithermal 8000 8000"PreborealUpper DryasAllerodLower DryasBollingOldest DryasArcticXie Hu -5 - -610,700 10,000-Pre-Cold -12,000-14,000-16,000-*After Duan et al. (1981).

141THE: LAST 10,000 YEARSChu (1973), the outstanding Chinese meteorologist,has studied the climate changes in Chinaduring the last 5000 years based on meteorologyand phenology records in Chinese historical literatureand materials found In archaeological studies,On the basis of Chu's works, the climatechange during the postglaciation in East China hasbeen roughly outlined (han et al., 1981) as follows:the Xie Hu cold period (10,700-8000 B.P.),5-6'C lower than today; the Yang Shao warm period(8000-3000 B.P.), 2-3'C higher than today; theZhou Han cold period (3000-1400 B.P.), 1-2°C lowerthan today; the Pu Lan Dian warm period (1400-500B.P.), 1-2'C higher than today: and the Little IceAge (500 B.P.-present), I-2'C lower than today.The climatic tendency over the last 10,000 yearsin East China roughly coincides with that of therest of the world, but there are some differencesin timing. Table 1 provides a comparative basefor reconstructing the palaeoclimate in permafrostregions of China.qinghai-Xizang PlateauFrom carbon-14 dating, we know that the peatburied in the middle section of Qinong at Yangbajainis 9180 + 100 years old. The involutions inthe overlying sand layer may have been formed inthe Xie Hu cold period (Pu et al., 1982), In thisperiod of dry climate and strong winds, dunes werewidespread over the terraces of the Tongtian, Tuotuo,and Fenghuo Rivers, implying less than 200 mmof precipitation annually. A wind-eroded landscapedeveloped in the East Kunlunshan, the eastslope (3000 m) of Riyue Shan, and the upper part(4600 m) of the Gongba relict mountain in the Dingribasin. The stratified deposits on the westslope (4000 rn) of Xiaonanchuan in Kunlunshan mayhave formed in this period (Cui, 1980a), The periglacialloess of this period is also well developed.The carbon-14 age of mst of the peat on theQinghai-Xizang Plateau is between 8000 and 3000B.P., implying a rise in temperature during theYang Shao warm period, i.e. the Holocene Hypsithermal.The 4- to 6-nrthick solifluction depositsin Fenghuoshan and the solifluction terrace,up to 10 m, in Tanggulashan are also evidence ofrising temperatures in this period. The periglacia1loess, formed in the Xie Hu cold period, usuallybecame part of the solifluction. The stabilizingof the dunes by vegetation reflected a warm,wet environment, with more than 400 mm of ptecipitation.Part of the dunes stabilized by vegetationwas covered by active solifluction. Accordingto Ding and Guo (19821, the average thaweddepth in the Holocene Hypsithermal was 15 m, whichmeans the permafrost had not disappeared entirelyat that time, although it had largely degraded.During the Zhou Han cold period, i.e. Neoglaciation,the temperature on the Qinghai-XizangPlateau dropped again. A group of fossil pingoshas been found at Xidatan (4300 m) in the northpart of the plateau. The carbon-14 age of itsequivalent layer is 7530 + 300 B.P. It seemslikely that these pingos formed in the Neoglaciation.If the altitude at which the pingos formedwas 100 m higher than the permafrost lower limit(Cui, 1980a), and accepting that the mountainshave uplifted 300-500 m since the end of theHypsithermal, it is inferred that the temperaturein the Neoglaciation was about 2°C lower thannow. The involutions of this period are widelydistributed on the plateau. In the north, theyare encountered on the first terrace at Naij Tal(3600 m) with a carbon-14 age of 4190 100 B.P.;in the south, they are found at Langkaze (4400 m)near Yamzho Yumco, Yali (4400 m), the Dingri basin(4300 m), and Yangbajain (4200 m), with a carbon-14 age of 3270 + 70 and 6130 i 90 B.P. Al theseindicate a cold environment at that time.Northeast ChinaFrom pollen analysis, it is known that duringthe Hypsithermal broad-leaf forest, consistingmainly of oak, elm, alder, and birch grew from theSanjiang plain to South Liaoning. The air temperatureat that time on the Sanjiang plain was about6-8'C, which is 2-4'C higher than today's. Taking1°C per degree of latitude as the lapse rate oftemperature, it is calculated that the temperatureto the north of Mangui was about O'C. Analysis oflight and heavy minerals in samples taken from adrill hole at Amur shows a large content of screematerial, which implies that the area to the northof Mangui had not been affected by the warm. wetclimate. Based on this evidence, Guo and Li(1981) have concluded that there were relict permafrostislands to the north of Mangui during theHypsithermal (Pig. 2). This ha6 been confirmed bythe calculations of Fu et aL. (1983).During the Neoglaciation, the temperaturedropped again. Involutions of the black-grey finesand and silt layer with hums (carbon-14 age of3010 i 80 B.P.) have been found in both the isolatedtaliks north of both the existing southernpermafrost boundary and the seasonally frozenground boundary south of it. In other words, duringthe Neoglaciation the permafrost exceeded today'ssouthern permafrost boundary.THE LAST 1000 YEARSZhang et al. (1981) have analyzed the ringsof a 900-year-old cypress tree (Sabina przewalskii- kom.) that is located at the upper tree limit(3760 m) at Tianjim (37"24'N, 99'56'E) in Qilianshan.Here variations of ring widths are mainlydue to fluctuations in air temperature, so theyreflect the temperature changes on the Qinghai-Xizang Plateau. The results of the analysis areshown in Figure 3.Chu (1973) has shown that there were two obviouscold periods during the last 1000 years inEast China. The first was in 1000-1200 A.D., andthe second was in 1400-1900 A.D. with temperatureranges of 1-2'C in the mean annual temperature.The latter corresponded to the Little Ice Age inEurope (1541-1890 A.D.). It was also indicated bythe results of the tree-ring analysis of the cypresstree at Tianjim in Qilianshan.During the cold period of the last 500 years,the climate in China still fluctuated between coldand warm periods (Table 2). Based on the pheno-

142FIGURE 2 Boundaries of permafrost during the late Quaternary (modified from Guo and ti, 1981). 1) Zone ofpresent-day permafromt; 2) Alpine permafrost; 3) Southern boundary of present-day permafrost; 4) Southernboundary of permafrost during late-Pleistocene; 5) Present-day boundary between "widespread continuous permafrost"and "Island or valley bottom permafrost"; 6) Inferred southern boundary of permafrost during theHypsithermal Interval (areas shown by horizontal cross hatch); 7) Involution layers; 8) Sand wedges. The Qsymbols refer to different aged deposits.I I '1 I I I I IYear, AB.1800 2000FIGURE 3 Climatic fluctuations during the last 1000 years. a) Running 10-yr mans of tree ring widthindices of Qilianshan cypress tree (Zhang et al., 1981). b) Temperature fluctuation during the last 1000years in China (Chu, 1973).

143$ 0.3 Whole EarthFIGURE 4, Comparison of average temperature changes since 1870 in the world and in China. Successive 5-yrmeans expressed as departures from the means for 1880-84, in the whole Earth (after Zhang Jiacheng),TABLE 2 Comparison of cold andtween East and West China.warm periods be-West ChinaEast China (from dendro-Periods (from phenology) climatology)1470-1520 A.D. 1428-1537 A.D.1620-1 720(especially 1622-17401650-1700)Cold 1840-1890 1797-1870After 1945(especially After 19241967-present)1550-1600 A.D. 1538-1621 A.D.Warm 1770-1830 1741-17961916-1945 1871-1923logical records. the cold period of the last 500years in East China can be divided into four smallercycles, including four periods of cooling andthree periods of warming with periodic lengths of50-100 years and a temperature range of 0.5-l.O°C.All these oscillations were recorded in the ringwidth variations of the cypress tree at Tianjim,but the time phase of East China is slightly differentfrom that of West China.By correlating the tree-ring width indicesand the air temperatures recorded at meteorologicalstations on the Plateau, it is deduced thatduring the last 500 years the temperature rangewas about 1.0-1.5"C, and the temperature in thecoldest period was 0.8'C lower than today.From the instrument records, the trends ofclimatic changes in Xining in West China coincidewith those of both East China and the rest of theglobe (Fig. 4). The warming in the Northern Hemisphere,which began in the 1880s, reached its maximumin the 1940s. But the ring-width index seriesshows that the warming trend in West China beganin the 18708, and reached its maximum in 1924.The time of transition from warming to cooling advancedby 10 to 15 years. The reason for this isnot yet clear.REFERENCESChu Kochen, 1973, A preliminary study on the climaticfluctuations during the last 5000 yearsin China: Scientia Sinica, V. 16, p. 226-56.Cui Zhijiu, 1980a, Periglacial phenomena and environmentalreconstructions on the Qinghai-Xizang Plateau, in Scientific Papers on Geologyfor International Exchange, No. 5: Beijing,Publishing House of Geology, p. 109-117.Cui Zhijiu, 1980b, On the periglacial mark in permafrostarea and the relation between glaciationand periglaciation: Journal of Glaciologyand Cryopedology, V. 2, p. 1-6.Cui Zhijiu and Xie Youyu, 1982, On Late Pleistoceneperiglacial environments in the northernpart of China, 11 Quaternary Geology and Environmentof China: China Ocean Press, p.167-171.Ding Dewen and Guo Dongxin, 1982, Primary researchabout the development history of permafrostin the Qinghai-Xizang Plateau, in Proceedingsof the Symposium on Glaciology and Cryopedologyheld by Geographical Society of China(Cryopedology), Lanzhou (1978): Beijing,Science Publishing House, p. 78-82.Duan Wanti, Pu Qingyu, and Wu Xihao, 1981, A preliminarystudy on climatic change during Quaternaryin China, & Proceedings of the NationalConference on Climatic Change (1978):Beijing, Science Publishing House, p. 7-17.Fu Liandi, Ding Dewen, and Guo Dongxin, 1983, Numericalcalculation about the evolution ofpermafrost in Northeast China, in Proceedingsof the Second Second National Conference onPermafrost, Lanzhou (1981): Lanzhou, GansuPeople's Publishing House, p. 165-169.Guo Dongxin and Li Zuofu, 1981, Preliminary approachto the history and age of permafrostin Northeast China: Journal of Glaciologyand Cryopedology, v. 3, p. 1-16.Pu Qinguy, Wu Xihao, and Qian Fang, 1982, Historicalchanges of the perma-frost along theQinghai-Xizang Highway, Q Proceedings of theSymposium on Glaciology and Crypedology heldby the Geographical Society of China (Cryopedology),Lanzhou (1978): Beijing, SciencePublishing House, p. 74-77.

144Shi Yafeng, Li Jijun, and Xie Zhichu, 1979, The the Quaternary: Lanzhou, Lanzhou Universityuplift of the Qinghai-Xiang Plateau and itsPress, p. 24-33.effect on China during ice age: Journal of Zhang Xiangong, Zhao Qin, and Xu Ruizhen, 1981,Glaciology and Cryopedology, V. 1, p. 6-11. Tree rings in Qilian Shan and the trend ofZhang Linyuan, 1979, The uplift of the Qinghal- climatic changein China, in Proceedings ofXizang Plateau and its effect on environment- the National Conference on Climatic Changea1 evolution during Quaternary in China, in (1978): Beijing, Science Publishing House,Contributions to Third National Conference on p. 26-35.

RESPONSE OF ALASKAN PERMAFROST TO CLIMATET.E.OsterkampGeophysical InstituteFairbanks, Alaska, USAPermafrost form by freezing from the groundsurface downward when mean annual surface temperatures(MAST) are less than O'C. The MAST is controlledby climate, so in this sense, permafrostis a product of climate. Climate may not be theonly controlling factor. For example, the geologicalsetting, topography, geothermal heat flaw,and vegetation may have a strong effect on localpermafrost conditions. This paper is a review ofpast and present climate in Alaska and the responseof permafrost to climate. Surface heat andmass transfer problems, the effect of air temperatureon MAST through the intervening snow and vegetationcover and active layer, and the effects ofprecipitation, winds, and water bodies are discussedelsewhere in this panel and will not beconsidered here.PAST AND PRESENT CLIMATEAn understanding of the present thermal regimeof permafrost and its thickness requires considerationof climate trends for many tens ofthousands of years. Figure 1 shows a composite oftrends in global and Alaskan climate. The USC/GARP (1975) curve represents the generalizedNorthern Hemisphere air temperature trend based onmid-latitude sea surface temperature, pollen records,and worldwide sea-level records. The secondcurve was selected from Brigham (1984) where theeffective diagenetic temperature (EDT) in the permafrostin the western Arctic was obtained fromamino acid geochronology. The data of Brigham andMiller (1983) require an EDT - -14'C for the past125,000 yr, which is = 4'C or more colder than thepresent MAST at Barrow and about 2°C colder thanthe MAST about a century ago (Lachenbruch et al.,1982). This suggests permafrost temperaturescolder than -14'C between the present and past interglacialperiods. The main features of the twoclimate models in Figure 1 are the two interglacialperiods separated by a period of about lo5years that was characterized by colder, oscillatorytemperatures. These models suggest that theglacial period 14,000-30,000 yr B.P. appears tohave had wan annual air temperatures (MAAT) ofabout -18'C or colder, assuming temperatures of =-9'C for the period from 8500-14,000 yr B .P. and =-12'C for the last 8500 yr (Brigham, 1984).These paleoclimate considerations suggestthat the permafrost on Alaska's North Slope wasthicker at the end of the last glacial period andthat it may still be thawing from the base in responseto the present, warmer MAST. This is avery simplified assessment, and a number of assumptions(e.g. the initial permafrost thicknessat the starting point of the calculations) areI I I I II I I I 1-24 ;cl io :5 1;o 2 5THOUSANDS OF YEARS B.P.FIGURE 1 (A) Generalized Northern Hemisphere airtemperaturetrends based on mid-latitude sea-surfacetemperature, pollen records, and worldwidesea-level records. Modified from USC/GARp (1975).(B) A possible model for the effective diagenetictemperature in permafrost (EDT) on the westernArctic Alaska coastal plain based on amino acidgeochronology. Modified from Brigham (1984).critical for determining the present state of thepermafrost. Obviously much more research on paleoclimatesand the effect of climate on permafrostis required. However, it should be noted that,given the unknowns of paleoclimate models and permafrost/climateinteractions, it may never be poosibleto do more than to arrive at general constraintson the paleoclimate models or a generalassessment of the present state of the permafrost,particularly for time periods extending back tothe last glacial period and beyond.The above statements apply to the thick permafroston Alaska's North Slope. The discontinuouspermafrost south of the Brooks Range is muchthinner and has much shorter response times tocliwte changes. Brown and Andrews (1982) havereviewed recent research on climate and permafrostin the North American Arctic, and Greenland andAlaskan weather records have been examined by Hamilton(1965) and Juday (1984). Hamilton (1965)suggests that the absence of pronounced regionaltrend differences indicates that a composite ofthe Alaskan data would be fairly representativefor the state as a whole. Figure 2 shows his compositeMhAT (mean annual air temperature) €orAlaska based on 8-yr running mans. Juday (1984)constructed the 5-yr running MAAT €or Barrow and145

146the University Experiment Station near Fairbanks(Fig. 3). These graphs are open to interpretation;however, one interpretation is that therehas been a general warming trend in Alaska sincethe late 1800s until the early 1940s amounting to= 1-2% This warming trend was followed by asharp cooling trend amounting to = l'C, whichlasted for about three decades until the mid-1970s. Since the mid-19708, there has been asharp increase in MAAT amounting to = 1-2°C. Anexamination of recent Alaskan weather records suggeststhat the climate warming since the mid-1970shas been statewide (Hoffman and Osterkamp, unpublishedresearch).While the interpretation of Alaskan weatherrecords is far from complete, it seem clear that,during the past century, Alaskan climate has experienceda warming trend followed by a shortcooler period and then a very recent sharp warming.Qualitatively, the Alaskan trend is similarto global climate trends. A key question is, whathas been the response of Alaskan permafrost tothese climate changes?I 1 I I1040 1880YEAR1880 1000 1020FIGURE 2 An Alaska composite of 8-yr runningmeans for the man annual air temperatures. Modifiedfrom Hamilton (1965).THERMAL REGIME OF AL ASK AN PERMAFROSTThere is little information available on thethermal regime of Alaskan permafrost. The mostextensive and long-term data are from holes loggedin the last three decades by the U.S. GeologicalSurvey, mostly near Alaska's arctic coasts (Lachenbruchet al., 1982; Gold and Lachenbruch, 1973;Lachenbruch and Marshall, 1969; Lachenbruch etal., 1966; Lachenbruch et al., 1962; Brewer,1958). Figure 4 shows four temperature profilesthat illustrate the main features of the thermalregime of the permafrost in these coastal areas.These are a strong curvature towards warmer temperaturesin the upper 100-160 m of the profiles,similar past MAST, similar and near-normal continentalheat flows, differing gradients (and permafrostthicknesses) that appear to be related tolarge variations in the local thermal conductivityand small variations in MAST, gradient contrastsacross the base of the ice-bearing permafrost forthe porous formations near Prudhoe Bay, and whatappear to be near-steady-state conditions (exceptfor the top 100-160 rn)?Osterkamp et al. (unpublished research) haverecently established 15 drill hole6 in permafroston a north-south transect of Alaska along thetrans-Alaska oil pipeline for the purpose of investigatingpermafrost/climate questions. Figure5 shows a preliminary temperature profile from ahole near Deadhorse Airport compared to a nearbyhole of Lachenbruch et al. (1982). The straightline is an extrapolation of the deeper thermalgradient to the surface and represents averagetemperatures a century in the past. The presentMAST -7'C or slightly colder, and the variationfrom past temperatures at the 50- depth was --14-74-6 -1000 1820 1040 1960 lS80YEAR4FIGURE 3 Five-year running means for the mean annualair temperatures at Barrow (upper graph) andthe University Experiment Station, Fairbanks (lowergraph). Modified from Juday (1982).FIGURE 4 Generalized temperature profiles in permafrostalong the arctic coasts of Alaska. Hodifiedfrom Lachenbruch et al. (1982).

147TEMPERATURE ('e)file shows a strong curvature toward warmer temperaturesin the upper 25 m. It is suggested thatthis curvature is a result of recent warmer MAST.Similar curvatures also occur in sow of the temperatureprofiles from other drill holes in bothcontinuous and discontinuous permafrost areas.20 DISCUSSION*- E30-in40 -A. Hole C60 -AT (sOm)-o.a FFIGURE 5 Recently measured temperature protile(B) in permafrost near Deadhorse. These data maybe compared to the profile extrapolated from depth(A) of Lachenbruch et al. (1982). AT (50 m)represents the temperature difference between theprofile extrapolated from depth and the measuredprofiles at the 503 depth.-5 10150 'IITEMPERATURE ('e)-0.5 0 0.5 1 .oHole t 2I IFIGURE 6 Recently easured temperature profile(June 1983) in permafrost on the University ofAlaska, Fairbanks campus.IThe Alaskan climate, as reflected in theU T , has had a very complex history over the pastcentury with an initial. oscillatory warming trendfollowed by a cooler period and then a very recent,sharp warming trend. Global climate changesappear to be similar to this pattern. Analysis ofthe weather data at Barrow, Fairbanks, and othersites in Alaska suggests that most, if not all, ofthe state was subject to this climate history(Hamllton, 1965; Juday, 1984; Hoffnvln and Osterkamp,unpublished research). Hamilton (1965) alsonoted that there was a minor latitudinal and longitudinallag in BOW of the oscillations associatedwith the warming trend prior to 1940. UndoubtedlyLocal variations from this general climatebehavior must exist; however, their extentand magnitude are unknown. The response of thepermafrost to these climate changes is containedIn its thermal regime (temperature profiles andthickness). This response is buffered by thyinterveningsnow and vegetation cover and the activelayer so that MAAT cannot be directly converted toMAST. In addition, climate changes, as reflectedby changes in MAAT, may be accompanied by changesin precipitation, wind, or snow cover, which canreinforce or negate the effect of changes in MAATor MAST. Nevertheless, it is fruitful to investigatepermafrost temperature profiles and thicknessesfor evidence about past changes in theMAST.A relatively simple permafrost/climate modelthat illustrates the response of the permafrost tosudden changes in the MAST and the time scales forthe response when the new surface temperature doesnot exceed O'C is shown in Figure 7. It is assumdthat a steady-state temperature conditionhas prevailed until time t = 0 and that at t > 0the surface temperature changed instantaneouslyfrom To to T, where T, < Tb, the melting temperatureat the base of the ice-bonded permafrost,which IS at x = X at time t = 0. A surface warmingof 3OC is assumed. The response of the permafrostto the new boundary condition is describedby the heat conduction equation3/4'C, which may be compared to the recent values where K is the thermal diffuslvlty of the permaof-8'C and - 1/2OC reported by Lachenbruch et frost.al. (1982). These differences could represent localvariations in the MAST and/or the effects of a The boundary conditions requirevery recent accelerated warming.Figure 6 shows a preliminary temperature T(O,t) = Tsprofile that was obtained in June 1983 as part ofthe permafrost/climate studies, noted from above,T(X,t) - Tbdiscontinuous permafrost at a site located on theUniversity of Alaska, Fairbanks campus. This pro- with the initial conditions given by

148TEMPERATURE PC)TABLE 1 Values of T, in yr, for fine-grained soilswith K = 38 m*-a-' and coarse-grained soils with= 50 m2-a-l where a, annum, is the time in yr.KThickness X (m) 25 50 100 400 600Fine-grained soils 4.1 16.4 66 1053 -Coarse-Rrained soils 3.1 12.5 50 800 1800where n is an integer and thetime constantT"X24Kdepends only on the permafrost thickness and itsthermal diffusivity.A full description of this type of approach,applied to the problem of thawing subsea permafrost,is given by Lachenbruch and Marshall(1977). T(x,t) is graphed for several elapsedtimes in Figure 7. Table 1 shows values for Tcalculated using eq. 8 for several permafrostthicknesses. The time constant T is associatedwith the time required for permafrost with fixedthickness X and fixed basal temperature Tb torespond to an instantaneous surface temperaturechange from To to T,.The heat balance at the permafrost base isFIGURE 7 Thermal warming model for the con inu uspermafrost zone (e.g. Prudhoe Bay, K = 50 m'-a-').The assumed initial equilibrium temperature profile(t = 0) and the final equilibrium temperatureprofile at t = t, with a permafrost depth ofX, are shown with the approximate temperatureprofiles for t = 10, 100, 600, and 1800 yr. Meltingat the base of the permafrost amounts to -3.5m during the first 1800 yr and is ignored in thisgraph.T(x,O) = (To-Ts) (1 - s, Xwhere L is the volumetric latent heat of the permafrost,+ is the porosity, q is the geothermalheat flux, Kf is the thermal conductivity of thepermafrost, and a constant heat flow, q, to thebase has been assumed.Substitution of eqs. 5, 6, and 7 in eq. 9gives the rate of melting of the permafrost base:Equation 1 can be solvedwhereby superposition withThe remining ti--dependent part of the solutioncan be obtained by separation of variablesand calculation of the Fourier coefficients consistentwith the boundary condirions so thatFigure 8 is a graph of eq. 10 for conditions similarto those at Prudh e Bay with q p 1.72~10~J(m2a)-' L+ = 1.2~10' J-m-3, Kf = 10.6x107J(ma'C)-', X 600 m, Tb = -l0C, Ts = -8"C,To = -ll°C, and T 9 1800 yr. This graph showsthat melting at the permafrost base (x = X) doesnot begin until the surface thermal dieturbancehas propagated to X, which requires a time periodon the order of 0.1~ or more. The melting rateincreases rapidly for 0.1~ < t < T. For t > T,the smutation of the right-hand side of eq. 10 approacheszero and, for times nuch longer than T,-dX/dt = 0.43 cm*a-l. For t < T the total lneltingamounts to about 3-4 my which justifies using thisapproach. The new equilibrium thickness,nnxsin -X

149-IPL 5 'wt0.4t /-ASVYrnTE 0.4s m-0-FIGLIRE 8 Melting rate -dX/dt at the ice-bondedFIGURE 9 Thermal warming model for the discontinpermafrostbase for the model and thermal parame-U~US permafrost zone (e.g. Fairbanks, K = 50ters shown in Figure 7.m -a- , X = 25 m). It is assumed that the warmingoccurs in two stages where the ground surfacewarm from -0.4' to O°C in the first stage andwould be reached in about 30,000-40,000 yr, assum- from 0 to 2.6OC in the second, where the firsting no further changes in surface temperature dur- stage lasts for T - 3-4 yr. The temperature proingthis period.file8 are shown for time t = 0, O.~T, 'I, ~ O T , andThis thermal analysis shows that the major t,.changes expected in the 600-m-thick permafrost atPrudhoe Bay, as a result of a ground surface temperatureincrease, are a general warming of the (1969) note that this surface warming was greaterpermafrost at all depths and melting at the base at Barrow than at Prudhoe Bay and also that aof the permafrost until it thine to a new equili- slight cooling occurred at Barrow in the decadebrium thickness. The warming of the permafrost prior to 1962.would begin immediately, the temperature profileA model for permafrost warming at sites inwould be nearly linear after a time t * T, and the the discontinuous zone, in which the new surfacetime required to reach a new equilibrium thickness temperature exceeds the melting temperature of thewould be several tens of thousands of years.permfrost, is shown in Figure 9. The warming isThis analysis is not very realistic in that considered to occur in two stages. In the firstit assumes a constant heat flow to the permafrost stage, the surface temperature warm instantanebaseand a sudden change in surface temperature.ously from To to T, - O"C, with the permafrostLachenbruch et al. (1982) used a more realistic base at Tb - O"C, and remains there for a time tmodel that accounts for the possible time varia-= r followed by a second warming from T, = 0°Ction in surface temperature. If the temperature to T, > O'C, which occurs for the time t > T. Achange at the surface of the permafrost can betotal surface warming of 3°C is assumed. Duringrepresented by a power law of the formthe first stage, the temperature profiles in thepermafrost can be obtained by solving the heatT(0,t) - AtnI2 n * 0,1,2 ...conduction equation as before. The solution(12)where A is a constant and t is the time since the 2To 1 -n2 r2 nnxT(x,t) = 1 ;- exp (7 t) sin x (14)start of the warming, then the temperature disn-1turbance at depth x and time t isis graphed in Figure 9 for several tiws duringthe first warming stage for conditions characteristicof coarse-grained soils in interior Alaska.Except for surface thawing, the value of r, andother tineand length scales, the results for thinwhere r (a) is the gamma function of argument B and thick permafrost are qualitatively similar.and in erfc (8) is the repeated integral of the Table 1 shows that, for thin permafrost in intererrorfunction of 8. Application of this type of ior Alaska (X = 25 m), the time scale required toapproach to permafrost temperature profiles alongbring the permafrost to temperatures very near itsAlaska's arctic coasts (Lachenbruch et al., 1982; melting point is t - T - 3-4 yr.Lachenbruch and Marshall, 1983) sug8ests that theThe rate at which the permafrost is thinnedcurvature found in the upper portion of the pro- from below can be obtained from the heat balancefiles represents a surface warming of 1.5-3'C dur- at the permafrost base (eq. 9). Substitution ofing the past century. Lachenbruch and Marshall eq. 14 into eq. 9 yields

1501.5 -TIME (a)ASYMPTOTE 1.46 Cm -0'FIGURE 10 Pielting rate -dX/dt at the ice-bondedpermafrost base for the model and thermal parametersshown in Figure 9.Figure 10 is a graph of eq. 15 €or coarse-grainedsoils and conditione appropriate to om interiorAlaska 7ites (1.e. LC$ - 1.2~10' J m-I, Kf =10.6~10 J (ma0c)-l, X = 25 m, Tb = OOC, andTo - -0.4'C). It is assumed that the heat flwq is the same as at Prudhoe Bay. Apparently only4-5 cm of the permafrost may be expected to meltat its base during the time period 0 < t < T. Fortimes much greater than T,- 81 9- 1.46 cm a-ldt L$During the second stage, t > T, it is assumedthat the surface temperature warms instantaneouslyto T, > O'C. The depth of thaw during thisstage can be calculated using the Stefan fomlawhich reduces toX' = 1.64 6 (18)for Kt = 6.2~10~ J (ma°C)-', T, = +2.6"C, andTo = O'C, and the conditions assumed above,where X' is in m and t is in yr. Equation 17 describesthawing from the ground surface downwardswhen the MAST exceeds O'C. The model assumes constantsurface temperatures during both stages andlinear temperature profiles near the surface (0 5x X) during the second stage; however, in reality,variable surface temperatures and the presenceof an active layer would make near-surface temperatureprofiles highly nonlinear.The thickness of the remaining permafrost atany time can be obtained by combining eqs. 15 and18. Apparently 185 yr or about two centuries.I would be required to thaw completely 25 m ofcoarse-grained permafrost under the assumed conditions.The final temperature profile would bethat shown for t- in Figure 9, which would beparallel to the subpermafrost temperature profileat t - 0. This assumes no further modificationsof surface temperatures during that period.The above analyses show that the permafrostresponse to climate variations includes changes inthe temperature profile, melting at the base, and,if the *ST > O"C, melting at the table. For timeperiods t 5 r,information on the changes in theMAST is contained in the temperature profile. Thethickest permafrost in Alaska, 629 m at Mikkelsen- Bay (Osterkamp and Payne, 198l), would have a r =2000 yr assuming thermal parameters similar toPrudhoe Bay. For time periods t > T, climate informationis available in the thermal gradients inthe permafrost and in its thickness. These relativelysimple models suggest that climate informationfor time periods of several tens of thousandsof years may be available in the thermal gradientsand thicknesses of the permafrost in the PrudhoeBay area. Harrison and Bowling (1983) have begunto analyze the data of Lachenbruch et al. (1982)in an effort to extract paleoclimate information.Preliminary analysis of temperature prof ileafrom interior Alaska such as that shown in Figure6 suggests that this warm, thin, discontinuouspermafrost is responding to warmer MAST. Curvaturein the top portions of the profiles appearsto be a result of a very recent warming (withinthe last decade). This permafrost (Fig. 6) is extremelywarm, within 0.4'C of thawing, with an approximatepast MAST near -1% If the surfacewarming shown in Figure 6 is characteristic ofother sites in interior Alaska then, given therange of permafrost conditions, somewhat warmerand thinner permafrost is presently thawing atboth the permafrost table and the base.The quantitative nature of these tentativeconclusions is difficult to ascertain, partly becauseof the non-uniqueness of the solutions andthe accuracy of the data, but primarily due to thesparsity of data. For example, with the MAST variationof eq. 12, Gold and Lachenbruch (1973) shwthat each of the cases n 0,1,2,3 reproduces thetemperature observations with a standard error ofO.0loC. Therefore, while all the models indicatea warming of the MAST during the last century, itis not possible to select between them. While theaccuracy of the available temperature data is verygood, the determination of therm1 conductivityand thermal gradients leads to relatively largeuncertainities in the heat flow data. For example,Lachenbruch et al. (1982) fouqd that the heatflow at Prudhoe Bay is 55 r8 mW m- . The correspondinguncertainty in the equilibrium thicknessof the ice-bonded permafrost is = 80 m.The precise relationships between changes inclimate and in the thermal regime of Alaskan permafrosthave not been established. However, theforegoing suggests that the permafrost is respondingtochanges in the W T during the last centuryand may still be responding to earlier climates.In addition, changes in the MAST over the past

151century, as determined by analyses of the permafrosttemperature profiles, are of the same magnitudeas the MAAT changes determined from Alaskaweather records.SUMMARYThe implications of climate change for permafrosthave already been noted by Brown and Andrews(1982), Goodwin et al. (1984), and Osterkamp(1984). Washburn (1980) has summarized most ofthe recent information on the use of fossil permafrostfeatures as temperature indicators. If thewarming trend of the past century and particularlyof the past decade continues, then substantialchanges noted by the above authors may occur inpermafrost areas.The data obtained from amino acid geochronologystudies show that the effective diagenetictemperature of Alaskan permafrost was = -14°C forthe past 125,000 years. Present and past interglacialperiods have been warmer, suggesting thatthe intervening glacial period was colder, with amean annual air temperature of - -18'C or colder.Alaskan weather records suggest an oscillatingwarming trend in air temperatures from the late1800s until the early 1940s of - 1-2'C, followedby three decades of cooler temperatures (= 1'C)until the mid-19708, when a sharp warming of1-2'C occurred. This accelerated warming trendis still under way.Temperature profiles from thick permafrostalong Alaska's arctic coasts all show a strongcurvature in the upper 100-160 m and near steadystateconditions otherwise. This curvature suggestsa mean annual surface temperature warming of1.5-3°C during the last century. A cooling of theMAST occurred in the decade prior to 1962. Recenttemperature profiles obtained in areas of discontinuouspermafrost in interior Alaska suggest thatthere has been a warming in the MAST since themid-1970s. The discontinuous permafrost may bemelting or freezing at the base, depending on itsthickness and thermal parameters. The main featuresof the climate trends of the past centuryappear to be reflected in the thermal regime ofthe permafrost.First-order estimates of the tine scales andmagnitudes of past changes in the mean annual surfacetemperature of permafrost areas can be madewith relatively simple models. These models showthat the permafrost response consists of curvaturein the temperature profile progressing downwardwith time, followed by slow melting at the permafrostbase and establishment of a new thermalgradient. If the MAST exceeds O'C, then meltingat the permfrost table would also occur. The resultsof applying these models to Alaskan permfrostshow that the time scales for curvaturein the permafrost temperature profiles range froma Eew years up to about 2000 yr. Melting at thepermafrost base proceeds very slowly, and the timescales required to establish an equilibrium thicknessof permfrost in response to surface temperaturechanges range from a century or less to manytens of thousands of years. When the MAST exceedsDOC, melting at the permafrost table also proceedsvery slowly, and a time scale of about a centuryis required to melt 10-20 m. These considerationsshow that a record of past climate is contained inthe temperature profiles and thickness of the permafrost.An understanding of the exact nature (magnitude,timing, regional trends) of past climatechanges and their effect on mean annual surfacetemperatures, permafrost features, and the thermalregime and thickness of the permafrost requiresmuch more detailed data, analyses, models, and interpretation.This understanding of permafrostclimateproblems is needed to assess the influenceof the present climate warming trend on permafrostand to anticipate changes in the permafrost thatwill have an impact on the environment and on humanactivities.ACKNOWLEDGMENTSI wish to thank J. Gosink, K. Kawasaki, andG. Weller for reviewing a draft of this manuscript.This research was supported by the AlaskaCouncil on Science and Technology, Grant No.W-81-03.REFERENCESBrown, J., and Andrews, J.T., 1982, Influence ofshort-term climatic fluctuations on permafrostterrain, & Carbon Dioxide Effects Researchand Assessment Program, Environmentaland Societal Consequences of Possible COP-InducedClimate Changes, DOE/EV/10019-02, V. 2,pt. 3: Washington, D.C., U.S. Department ofEnergy.Brewer, M.C., 1958, Some results of geothermal investigationsof permafrost in northern Alaska:Transactions of the American GeophysicalUnion, V. 39, no. 1, p. 19-26.Brigham, J.K., 1984, Marine stratigraphy and aminoacid geochronology of the Gubik formation,western Arctic Coastal Plain, Alaska: Universityof Colorado, Boulder, Colorado, Ph.D.dissertation.Brigham, J.K., and Miller, G.H., 1983, Paleotemperatureestimates of the Alaskan Arcticcoastal plain during the last 125,000 years.Paper presented at the poster session of theFourth International Conference on Permafrost,Fairbanks, Alaska.Gold, L.W., and Lachenbruch, A.H., 1973, Thermalconditions in permafrost - A review of NorthAmerican literature, & Proceedings of theSecond International Conference on Permafrost,Yakutsk: Washington, D.C., NationalAcademy of Sciences, p. 3-23.Goodwin, C.W., Brown, J., and Outcalt, S.I., 1984,Potential responses of permafrost to climticwarming, Proceedings of a Conference onthe Potential Effects of Carbon Dioxide-InducedClimatic Changes in Alaska (J.H. Mc-Beath, ed.): Fairbanks, University of Alaska,Misc. Pub. 83-1, p. 92-105.Hamilton, T.D., 1965, Alaskan temperature fluctuationsand trends: Analysis of recorded data:Arctic, V. 18, no. 2, p. 105-117.Harrison, W.D., and Bowling, S.A., 1983, Paleocli-

152mate implications for Arctic Alaska of thepermafrost at Prudhoe Bay. Paper presentedat the poster session of the Fourth InternationalConference on Permafrost, Fairbanks,Alaska.Juday, G.P., 1984, Temperature trends in the Alaskaclimate record: Problems, update, andprospects, Proceedings of a Conference onthe Potential Effects of Carbon Dioxide-Induced Climatic Changes in Alaska (J.H.McBeath, ed.): Fairbanks, University of Alaska,Misc. Pub. 83-1, p. 76-91.Lachenbruch, A.H., Brewer, M.C., Greene, G. W. , andMarshall, B.V., 1962, Temperatures in perma-frost, 11. Temperature - Its Measurement andControl in Science and Industry, V. 3, pt 1:New York, Reinhold Publishing Co., p. 791-803.Lachenbruch, A.H., Greene, G.W., and Marshall,B.V., 1966, Permafrost and the geothermal regimes,Environment of the Cape Thompson Region,Alaska, Chapter 10: Washington, D.C.,U.S. Atomic Energy Commission, Divison ofTechnical Information, p. 149-165.Lachenbruch, A.H., and Marshall, B.V., 1969, Heatflow in the Arctic: Arctic, V. 22, p. 300-311,Lachenbruch, A.H., and Marshall, B.V., 1977, Subseatemperatures and a simple tentative model

CLIMATE CHANGE AND OTHER EFFECTS ON PERMAFROSTM. SmithDepartment of Geography, Carleton UniversityOttawa, CanadaThis is not a review of climate and permafrostrelationships. Other contributors have addressedthis, but it might be useful to restate anumber of basic ideas about climate and permafrostgiven the considerable interest in the implicationsof climate change for permafrost conditions.After a brief summary of so= basic ideas, threebroad questions are posed.Obviously, the occurrence of permafrost dependson climate, since climate, in some way oranother, determines the temperature at the surfaceof the earth. Many discussions of climate andclimate change seem to focus almost exclusively onthe factor of temperature, but it must be realizedthat climate is far mote complex than this, andthat changes in precipitation and other factors ofclimate are also very important. In addition,more than just climatic conditions prescribe thesurface temperature regime, under which permafrostmay or may not be present. However, when climatedoes change as shown in Figure 1 -- the temperaturechange over roughly the last century or so --then ground temperatures can also change (Gold andLachenbruch, 1973; Osterkamp, this volume). Bowever,ground thermal conditions can change for avariety of other reasons, some of which are nonclimatic,and some of which have implications for,or Feedbacks with, climatic processes.For instance, fire can produce disruptions ofsurface cover and change ground thermal conditions.Exposure of ice-rich sediments by rivererosion can initiate spontaneous and continuingthaw of the materials. Snow banks can form eitherthrough changes in climate, including precipitationand wind, or by geomorphic or vegetationalchanges. A poster paper by Bowling (this conference)illustrates the effects of snow cover on theground thermal regime in the absence of otherkinds of climate change. Vegetation differencescan produce substantial variations in ground thermlconditions between sites. Figure 2 shows datafrom two adjacent sites, where organic material ispresent at one and not at the other. As can beseen, quite different ground thermal regimes developunder the same climtic conditions. Lastly,there is a range of human disturbances that bringabout changes in the ground thermal conditions.Jahns and Heuer (1983) have suggested how thiscould be exploited in mitigative frost heave, byutilizing the disruption in surface conditions tocounteract freezing beneath a pipeline. Thermokarstcan be initiated by surface disturbance duringconstruction and such features can then havefeedbacks to natural climatic and microclimaticprocesses that may amplify or diminish the influenceof such disturbances.There is of course considerable debate overthe possible course of the earth's climate overFIGURE 1 Mean hemispheric (0-80"N) changes in airtemperature since 1880 (from Schneider, 1976).765-0w 4K3I-2i 3I-210Organic4 8 12 16 20HOURS (Local Time)MEANFIGURE 2 Mean diurnal. 10-cm ground temperatureregirnes at adjacent sites in the Mackenzie Delta(from Smith, 1975).the next 50 to 75 years. Conventional wisdom doespoint to at least a doubling of atmospheric carbondioxide by the middle of the next century, but theimplications of this for climate are less certainand there is no unanimity on just what will happen.We do know from the past that changes inarctic climte, especially temperature, are threeto five times greater than for the northern hemi-I153

154sphere as a whole. In coastal regions of the Arctic,climate changes are complicated by simultaneouschanges in the ice regime, but the general implicationsof C02-induced climate change would bea warming in the Arctic with a likely increase inprecipitation (Harvey, 1982). If we accept thisas a hypothesis valid for the next 100 years, thenthe following questions might be posed.First, how can we assess the effects of climatechange on permafrost conditions, given thatlocal conditions exert such strong influences onground thermal regime, as discussed by Smith andRiseborough (1983). Unfortunately there is adearth of published information on ground temperatureregimes at neighboring sites over long periodsof time. There appears to be no report in theliterature of any monitoring network of shallowpermafrost temperatures that has been continued ona regular basis €or any length of time. Figure 3is based on a few years' data from Brown (1978);it illustrates that, within a small area, there isconsiderable variation in the thermal regime fromsite to site and from year to year, For example,the warmest year was 1976 at some sites, but 1975at others. Thus we cannot expect individual locations,where permafrost is present, to respond inthe same way to the same climate-forcing function;there are intervening processes that have to beunderstood before we can predict the influence ofclimate and climate variation on permafrost conditions,How can we best address this particularproblem of the complexity introduced by the variationin local conditions? Goodwin et aL. (1984)have addressed this issue, using a numerical energybalance model.Secondly, is the likely rate and magnitude ofpermafrost change due to climate likely to beless, equally, or more Important than changes dueto other natural processes, such as the spontaneousthawing of ice-rich sedient exposed by riverbankerosion or fire? A corollary to this is, howwill climate change affect the rate of such naturalprocesses? We have initiated some work in thecentral Yukon to monitor the year-by-year retreatof retrogressive thaw flow slides to see if thereis any relationship between the rate of retreatand climatic conditions. Such studies could berepeated in various places. Lastly, are changesin the permafrost regime resulting from possibleclimate change likely to be important considerationsin northern geotechnical engineering? GivenYEARS0 5 10 15 20 25double snowfall1 Rock2 Tlll3 Palsa4 DepressionV-20c- 1973 1974 ' 1975 ' 1976DATEI1FIGllRE 3 Ground temperatures at 1.06-m depth for FIGURE 4 Predicted annual maximum active layerfour sites at Churchill, Manitoba (from Smith and development for different sites under a uniformRiseborough, 1983).climatic warming trend (from Smith and Iilseborough,1983).

155that structures in such environments are designedto be in some equilibrium with the natural thermalconditions, what are the implications if the naturalbackground conditions themselves change?Figure 4 shows some attempts to predict the rateof permafrost recession under assuraed climaticwarming over the next 25 years at a number ofsites deemed to be representative of discontinuouspermafrost near Whitehorse, Yukon. As can be seenfor various kinds of site conditions, the degradationof permafrost due to natural warming may bebetween 2 and 5 m over the period, surely not aninsignificant amount for thaw-sensitive structures.REFERENCESBrawn, R.J.E., 1978, Influence of climate and terrainon ground temperatures in the continuouspermafrost zone of northern Manitoba and KeewatinDistrict, Canada, Proceedings of theThird International Conference on Permafrost,Edmonton: Ottawa, National Research Councilof Canada, V. 1, p. 15-21.Gold, L.W. and Lachenbruch, A.H., 1973, Thermalconditions in permafrost - A review of NorthAmerican literature, &Proceedings of theSecond International Conference on Permafrost,Yakutsk: Washington, D.C., NationalAcademy of Sciences, p. 3-23.Goodwin, C.W., Brown, J., and Outcalt, S.I., 1984,Potential responses of permafrost to climaticwarming, Proceedings of a Conference onthe Potential Effects of Carbon Dioxide-InducedClimatic Changes in Alaska (J.H.McBeath, ed. 1: Fairbanks, University ofAlaska, Misc. Pub. 83-1, p. 92-105.Harvey, R.C., 1982, The climate of arctic Canadain a 2% CO2 world. Canadian Climate CentreReport No. 82-5.Jahns, LO,, and Heuer, C.E., 1983, Frost heavemitigation and permafrost protection for aburied chilled-gas pipeline, Proceedingsof the Fourth International Conference onPermafrost, Fairbanks: Washington, D.C., NationalAcademy of Sciences, p. 531-536.Schneider, S.H., 1976, Is there really a food-climatecrisis? Atmospheric Quality and ClimaticChange, University of North Carolina atChapel Hill, Studies in Geography No. 9, p.106-143.Smith, M.W., 1975, Microclimatic influences onground temperatures and permafrost distribution,Mackenzie Delta, N.W.T.: CanadianJournal of Earth Sciences, V. 12, p. 1421-1438.Smith, M.W. and Riseborough, D.W., 1983, Permafrostsensitivity to climate change, fi Proceedingsof the Fourth International Conferenceon Permafrost, Fairbanks: Washington.D.C., National Academy of Sciences, p. 1178-1183.

RECONSTRUCTIONS AND FUTURE PREDICTIONS OF THE EFFECTS OF CLIMATE CHANGEJ.T.GrayDepartment of Geography, UniversityMontreal, Canadaof MDntrealThere are three main purposes for studyingthe relationships between climate change and thegeothermal regime in cold environments.In the first place, we may wish to interpret,for a given region, how documented climate changein the past ought to have affected ground temperaturesand hence permafrost distribution and thickness,ground ice content, and active layer depths.Variations in these properties may then be inferredto have played a role in the physical,chemical, and biological processes active at andimmediately below the ground surface. Thus, gooddocumentation of past climate change has the potentialof explaining fluctuations in these processeswhen interpreted by Quaternary specialistsin such fields as geomorphology, pedology, hydrology,geochemistry, and plant ecology.In the second place, we may wish to reversethe procedure and try to use fluctuations in thevarious physical, chemical, and biological processesas indicators of changes in the geothermal regimeand hence as imprints of climate oscillationsfor a given region. "ne aim would then be to tryto establish the age, trend, and amplitude ofthese oscillations.In the third place, we may wish to predictthe effects of future climate change on the thermalregime, and more specifically on the permafrostand active layer conditions. At one levelwe may wish to assess the effects of such futurechange in terms of the possible thermal disturbanceto the near surface environment of man-inducedmicro-climatic modifications, resulting fromengineering projects, on various scales. Theplanned reservoir construction in the Great WhaleRiver basin of Northern Quebec, although presentlyshelved, is an interesting example of such a projecton a very large scale. The Trans-AlaskaPipeline and the pipeline planned in the MackenzieValley in northwestern Canada are examples of suchmodification on a somewhat smaller scale. At asecond level, we may wish to assess the long-termeffects on a regional or even a continental scaleof lower atmosphere warming and cooling trends.In this regard reference may be made to a possiblewarming trend related to the very significant increasein the CO2 content of the atmosphere in recentyears (Watts, 1980).Whichever of these three goals Interests usas researchers, it is clear that a key element isthe quality and continuity of the climate dataitself. In this regard, I would like to brieflyraise a number of points about the different typesof climate data available for reconstructions ofgoethermal regiroes for the Holocene interval inperiglacial regions, and then I would like to makea few remarks concerning the kind of data we willneed to predict future climate change.The climate data can be conveniently eubdividedinto three categories. In the first place,data are available for a sparse netVFork of arcticmeteorological stations for a period rarely exceedingthe last 50 yeara. 'he most useful datafor studies of the ground thermal regime that areoften available are on air temperatures, precipitation.snowfall, snow cover, and global radiation.However, the very useful parameter of surface temperaturefor a variety of cover types is almostnever available. It rmst be derived using correctiveindices that vary according to radiation andthe snow cover characteristics of the various surfaces.hnardini's "n" factor correction (Lunardini,1978) is one such corrective index.The second type of data available to us isrecorded in temperature logs that have been obtainedfrom deep drill holes in arctic regions(Lachenbruch and Marshall, 1969; Taylor and Judge,1979; Judge et al.. 1981; Osterkamp and Payne,1981; Poitevin and Gray, 1982; Pilon, 1982). Thefluctuations in the ground temperature profilesbeyond the zone of zero annual amplitude reflectchanges in the mean annual surface temperatures atthe site, but interpretation of the amplitude andperiodicity of these temperature fluctuations isnot straightforward. A number of corrections haveto be applied to the temperature profiles to takeaccount of thermal conductivity contrasts as wellas of terrain variations in the vicinity of thedrill hole, and assumptions have to be made concerningthe geothermal flux from the interior ofthe crust (Taylor and Judge, 1979; Pilon, 1982).The third possibility is the use of proxyclimate data obtained from a series of indices ator below the ground surface. These indices arebased on geomorphologic, pedologic, geochemical,and vegetational information. They can take theclimatic record much farther back than the mteorologicaldata, generally using radiocarbon datingfor chronological control. However, use of suchproxy data results in problems of Interpretation,which necessarily imply a certain degree of subjectivityand a fairly high margin of error in derivationof the timing, direction, and amplitudeof climate fluctuations. In this regard, let usexamine one of the best established indices ofclimate change - pollen analysis.Pollen spectra from successively depositedlayers of organic material in peat bogs and lakebeds have frequently been used to reconstructformer vegetation assemblages at given sites (Faegriand Iversen, 1964; Short and Nichols, 1977;Richard, 1977, 1978). Because of the relationshipbetween vegetation associations and climate zones,it becomes possible to draw some inferences aboutformer climates from the pollen stratigraphy and,through dating of the organic material, to have156

157sow chronological control on climate transitions.A number of problems mst be taken into account,however. In the first place, the pollen spectrain arctic and subarctic regions do not only reflectthe pollen rain derived from the local vegetationcommunity, but also significant and perhapstemporally variable long-distance transport fromforest regions to the south (Nichols et al., 1978;Elliott-Fisk et al., 1982). Secondly, it is presumedthat there is a synchronism between vegetationchange as reflected in the pollen stratigraphyand climate change acting as the causalfactor. Richard (1977), in discussing climaticinterpretation of pollen diagrams, suggests thatvegetation succession towards a state of equilibriumwith the climatic milieu is relatively rapid,well within the temporal precision of thetechnique for most basins of sedimentation. Finally,although palynologically determined changesIn vegetation cover may give an index of the directionof climate change in terms of a deteriorationor amelioration of growing conditions, it isvery difficult to translate such change into meaningfulterm for geothermal studies. Andrews etal. (1980) and Andrews and Nichols (1981) have attemptedto use pollen transfer functions, usingknowledge of modern pollen rain at control sitesnear eteorological stations across a range ofvegetation zones in the Eastern Canadian Arctic,to accurately reconstruct temperature conditionsin the growing season during the Late Holocene interval.However, the geothermal regie is alsorelated to winter temperature conditions and tosnow cover, and these parameters cannot as yet bemodelled by the pollen transfer functions.Other proxy data from vegetation, such asleO/ l60 ratios in buried tree trunks or in peat,tree-ring studies in living vegetation (Cropperand Fritts, 1981) and in buried macro fossils(Gagnon and Payette, 1981), geomorphological criteriasuch as the distribution of active and inactiveperiglacial landforms (Harris, 1982), allpresent similarly serious obstacles to thestraightforward interpretation of climate changeas it influences the geothermal regime. In additionto the problem of interpretation, there areoften serious problems resulting from difficultiesin establishing a ti- scale €or the observedchanges, either due to a total lack of in situ organicmaterial for 14C dating or due to the largeerrors inherent in I4C data obtained from some organicmterials--such as soils.As a result of the various problems associatedwith proxy data, it may be appropriate to askthe following question when considering the use ofpaleoclimatic data for given sites in arctic regionsfor geothermal studies; Is it preferable touse a fragmentary record of locally derived proxydata with moderate to poor chronological control,or is it better to extrapolate to the given sitefrom a distant region, relatively continuous recordsof climate change, perhaps using so* kind oftransfer function based on present-day climaterecords? In this regard, we might mention thevery complete climate records based on the l8O/ l60cores available from Camp Century on the Greenlandice cap (Dansgaard et al., 1970) and from theDevon Island ice cap in the Eastern Canadian Arctic(Koerner and Fisher, 1981). The latter pathmight appear at first glance to be a reasonableone, but rmst be followed cautiously. Recent climaterecords for eastern and western Arctic regionsof North Anerica (Fig. 1) do not show perfectsynchronism in terms of warming and coolingtrends. I would venture to suggest that while theregionally available proxy data are undoubtedlydifficult to relate to mean annual ground surface-12--13-PointBarrow, Alaska-14 1 I 1 I1943 1955 1965 1915-21Fairbanks, Alaska11P45 1955 1965 1975I I I 11S45 1955 1985 1915'7 Nitchequon, Quebec-II I I I1845 1955 1965 1875FIGURE 1 Eight-year running mean for annual airtemperatures from 1940 to 1980 for selected stationsin arctic North America. A-1 and A-2 showdata for stations in the tundra and boreal forestzones of Alaska. B-1 and B-2 show data plottedfor corresponding vegetation zones in northernQuebec.A-IB-1B -2

158temperatures, they do offer potentially valuabletools for the reconstruction of climate change ifthey can be combined with a feu deep hole temperaturelogs. Taylor and Judge (1979) have shownthat knowledge of the general direction and age ofclimate trends can, through application to thegeothermal data, be used to reconstruct the amplitudeof such trends.One major difficulty vi11 always remain inthe use of the proxy data for paleoclimate reconstructions.The record, as regards detection ofchange in the various indices, the data of suchchange, and the derivation of paleotemperaturecurves, will always become progressively more impreciseas one goes backward through time.With regard to prediction of future effectsof climate change on permafrost and active layerconditions, it might be appropriate to suggest theestablishment of a series of monitoring stationsassociated either with arctic weather stations orwith long-term construction projects. Brown's researchin Keewatin (Brown, 1978) and the data obtainedat the McGill Subarctic Research Laboratoryat Schefferville in Northern Quebec (Adams andBarr, 1973; Nicholson, 1978, 1979) represent veryisolated examples where multi-year acquisition ofground surface temperatures through the variousseasons has been attempted. The Scheffervilledata have been obtained for a 25yr period, buteven there the record is rather broken. What isneeded for the North American Arctic is a seriesof recording stations from the eastern and westernarctic regions for both the continuous and discontinuouspermafrost zones. As wel as standard meteorologicaldata, each installation should beequipped to measure ground surface temperature,snow pack conditions, and ground temperature profiles(at least to a depth of about 5 m) for avariety of surface cover types in the vicinity ofthe installation, In this regard, long-term monitoringactivities planned in association with thefuture Mackenzie Valley pipeline in the vicinityof Norman Wells in the Northwest Territories(Pilon, pers. commun.) should provide good datarequired for future prediction of the effects ofclimate change, at least for the western arcticregions.REFERENCESAdams, W.P. and Barr, W., 1973, Annotated bibliographyof the McGill Subarctic Research Papers(1954-1970): Revue de Ggographie de Montreal,V. 27, no. 4, p. 391-412.Andrews, J.T., Mode, W.N., and Davis, P.T., 1980,Holocene climate based on pollen transferfunctions, eastern Canadian Arctic: Arcticand Alpine Research, v. 12, no. 1, p. 41-64.Andrews, J.T. and Nichols, H., 1981, Modern pollendeposition and Holocene paleo-temperature reconstructions,central northern Canada: Arcticand Alpine Research, v. 13, p. 387-408.Brown, R.J.E., 1978, Influence of climate and terrainon ground temperatures in the continuouspermafrost zone of Northern Manitoba and KeewatinDistrict, Canada, Proceedings of theThird International Conference on Permafrost,v. 1: Ottawa, National Research Council ofCanada, p. 15-21.Cropper, J.P. and Fritts. €LC., 1981, Tree-ringwidth chronologies from the North AmericanArctic: Arctic and Alpine Research, V. 13,no. 3, p. 245-260.Dansgaard, W., Johnsen, S.J., Clausen, H.B., andLangway, C.C. , Jr., 1970, Ice cores and paleoclimatology,& Radiocarbon Variations andAbsolute Chronology (I.U. Olsson, ed.),Stockholm: Almquist and Wiksell, p. 337-351.Elliott-Fist, D.L., Andrews, J.T., Short, S.K, andMode, W.N., 1982, Isopoll maps and an analysisof the distribution of the modern pollenrain, eastern and central northern Canada:Wographie Physique et Quaternaire, V. 36,no. 1-2, p. 91-108.Faegri. K. and Iversen, J., 1964, Textbook of pollenanalysis: Copenhagen, Monksgaard.Gagnon, R. and Payette, S., 1981, FluctuationsHoloches de la limite des forets de dldze(Rivieke aw Feuilles, Nouveau4)dbbec: GographiePhysique et Quaternaire, V. 35, no. 1,p. 57-72.Harris, S.A., 1982, Identification of permafrostzones using selected permafrost landforms,Proceedings of the Fourth Canadian PermafrostConference (Roger J.E. Brown Memorial Volume)(H.M. French, ed.): Ottawa, National ResearchCouncil of Canada, p. 49-58.Judge, A.S., Taylor, A.E., Burgess, M.M., andAllen, V.S., 1981, Canadian Geothermal DataCollection - Northern Wells, 1978-1980, GeothermalSeries No. 12: Ottawa, GeothermalService of Canada, Earth Physics Branch,E.M. ReKoerner, R.M. and Fisher, D.A., 1981. Studyingclimatic change from Canadian high arctic icecores: . Syllogeus (C.R. Harrlngton, ed.), no.33, Museum of Natural Science. p. 195-218.Lachenbruch, A.H. and Marshall, B.V., 1969, Heatflow in the Arctic: Arctic, v. 22, p. 300-311.Lunardini, V.J., 1978, Theory of n-factors andcorrelation of data, Proceedings of theThird International Conference on Permafrost,V. 1: Ottawa, National Research Council ofCanada, p. 40-46.Nichols, H., Kelley, P.M., and Andrews, J.T.,1978, Holocene paleowind evidence from palynologyin Baffin Island: Nature, v. 273, p.140-142.Nicholson, F.H., 1978, Permafrost distributionand characteristics near Schefferville, Qu6-bec: Recent studies, Proceedings of theThird International Conference on Permafrost,v. 1: Ottawa, National Research Council ofCanada, p. 427-433.Nicholson, F.H., 1979, Permafrost spatial and temporalvariations near Schefferville, Nouveau-Qu&ec: Gdographie Physique et Quaternaire,v. 33, no. 3-4, p. 265-278.Osterkamp, T.E. and Payne, M.W., 1981, Estimatesof permafrost thickness from well logs innorthern Alaska: Cold Regions Science andTechnology, V. 5, p. 13-27.Pilon, J.A., 1982, Etude de la couche active et dupergdlisol dans la rggion de Baie aux Feuil-

159les, Ungava. Unpublished Ph.D. dissertation,Ddpt. de Gbographie, Universitd de MontrBal.Poitevin, J. and Gray, J.T., 1982, Distribution dupergllisol dans le bassin de la Grande Rivi-Bre de la Baleine, Qugbec: Naturaliate Canadien,V. 109, p. 445-455.Richard, P., 1977, VBgetation tardiglaciaire duQudbec dridional et implications pal6oclimatiques:CIographie Physique et Quaternaire,V. 31, no. 1-2, p. 161-176.Richard, P., 1981, Paleoclimatic significance ofthe late Pleistocene and Holocene pollen recordin south central. Quebec, QuaternaryPaleoclimate (W.C. Mahaney, ed. 1, Norwich,Geo. Book, p. 335-360.Short, S.K. and Nichols, H., 1977, Holocene pollendiagram from subarctic Labrador-Ungava; Vegetationalhistory and climatic change. Arcticand Alpine Research, v. 9, p. 265-290.Taylor, A. and Judge, A,, 1979, Permafrost studiesin Northern Quebec: Gdographie Physique etQuaternaire, V. 33, no. 3-4, p. 245-251.Watts, R.G., 1980, Climate models and COP inducedclimatic changes: Climate Change, V. 2, p.387-408.

Soviet ContributionsThis section of the volume contains additional Soviet contributions to theconference. These include invited (p. 163) and contributed (p. 195) papers andtranslations of abstracts from a special conference volume of papers publishedin the Soviet Union (p. 315). (Problems of Geocryology, P.I. Melnikov, Editorin-Chief,Nauka, Moscow, 1983, 280 pp.) The translated abstracts were providedby the National Research Council of Canada. The invited papers were presentedin a special session of the conference. The present version of the invited paperswas translated by William Barr, University of Saskatchewan. As was thecase with the first proceedings volume, the camera-ready copy for the Sovietcontributed papers was prepared under the direction of the U.S. Organizing Committee,following revision by English-speaking readers. However, no attemptwas made to standardize the transliteration, terminology or quality of thetranslations. The Soviet papers were accepted for publication on the basis ofSoviet review prior to submission to the U.S. Organizing Committee.

Invited Soviet PapersMAJOR TRENDS IN THE DEVELOPMENT OF SOVIET PERMAFROST RESEARCHP. I. Mel'nikovpermafrost Institute, Siberian BranchAcademy of Sciences, Yakutsk, USSRThe author presents an overview of trends and achievements in Soviet permafrostresearch in recent years. He stresses both the progress in "pure science" areasand in practical applications of permafrost research. Within the first categorywould fall a major study (including mapping) of the geothermal heat in the fluxpermafrost zones; complex studies of energy exchange between soil, vegetation andatmosphere; and predictive studies of the possible impact on the permafrost of thewidely publicized global warming trend to due the accumulation of CO, in theatmosphere. A wide range of studies with a more practical flavor has also beenundertaken. These include a study of naled; (icings) in the mountains of SovietCentral Asia with a view to possible water supply; of mapping permafrost and predictionof the impact of development in the BAM zone; reconmendations as to environmentalprotection in the gas fields of northern West Siberia; and studies of thepotential use of underground storage chambers in permafrost, to name only a few.Geocryology, the science of frozen earth mater- At the present time the Permafrost Institute ofials, studies the composition, structure, con- the Siberian Section of the Academy of Sciences ofditions of formation and history of development of the USSR plays a leading role throughout the countryfrozen, freezing and thawing earth materials, and in this area of science. Moscow State University,also the processes and phenomena occurring in this the Institutes af the Ministry of Geology of thezone of the earth's crust, Perennially frozenUSSR, Gosstroy, and of other ministries and organimaterialsoccupy one quarter of the area of the zations have made a significant contribution to thecontinents, including half of the territories of development of this science.the USSR and Canada, three quarters of the area of Co-ordination of the geocryological researchAlaska, considerable parts of China and Mongolia, carried out by academic and departmental researchthe northern parts of the Scandinavian countries, institutions and planning organizations in USSR theand the whole of Greenland and Antarctica.is effected by the Scientific Council on TerrestrialAs a discipline geocryology emerged in the 19208, Cryology of the Academy of Sciences of the USSR.i.e. during the Soviet period. GeocryologicalIn our country geocryological research is plannedresearch in the USSR began to develop intensively on a multi-disciplinary basis; it involves thein the thirties in connection with the economic integrated combination of projects of a general,development of the northern areas where a range of thermophjrsical and engineering nature. Basicnatural resources is concentrated, includingresearch into either theoretical or regional geomineralswhich are rare, very valuable, unique or cryology embraces several problems.in wry short supply in the country as a whole. We study the thermophysical principles of theThe development of the productive capacity of formation and development of the cryolithozone.Siberia was critically complicated by the presence Investigations are under way into the relationshipbetween the earth's thermal fields and geologicalstructures, into the evolution of the thermal stateof the cryolithozone under natural conditions andunder the influence of human activities, and intofor the rational extraction of minerals, to develop the laws governing the processes of heat exchangeresearch into groundwater and to find new, effec- in the atmosphere/vegetation/soil system.tive techniques for exploiting it, and to perfect As a result of the research which has beentechniques for improving agricultural lands incarried out we have identified the conditionsterms of both water balance and temperature. controlling surface temperatures and the freezingof permafrost. It was necessary to develop basictechniques and to work out special methods forconstructing housing and industrial buildings,pipelines, roads for various purposes and airfields,163

164of the ground under the influence of the climate The method of permafro 'St-f aci es analysis hasand of heat exchange with the atmosphere under been introduced into the practical side of geovariouslandscape conditions and in various environ- cryological research. Cryogenic textures aremental zones. The thermal regime of the materials classified according to geological-genetic prinhasbeen defined for the main geostructures of ciples and a geological model of how they formed aNorthern Asia: the West Siberian plate, theterrestrial and submarine freezing proceeded hasSiberian platform and the Verhkoyansk-Chukotka fold been proposed.mountain area.On the basis of permafrost facies analysis ofFor all the permafrost zones in these regions we paleontologically dated deposits in type sectionshave compiled the first map of the magnitude of the in Yakutiya it has been shown that the age of theinternal geothermal heat flux. We have identified permafrost in the Aldan basin considerably exceedsareas with very low geothermal heat flux (the center 300,000 years and that within the boundaries of itsof the Siberian platform) and with very high geo- present distribution permafrost has never totallythermal heat flux (the Verkhoyansk mega-anticlin- disappeared. There are data to support the existorium),and also the peculiarities of the thermal ence of stable permafrost in the Kolyma lowland inregimes of depressed structures within which are the early Pleistocene, i.e. approximately 1.5 to 2deposited the deposits of oil and gas on theSiberian platform. It has been established thatdisequilibrium permafrost is widely developed; itis anomalously thick and has an anomalous temperatureregime, which does not correspond to thepresent climate and retains features of the coldperiods of the past.Theories of geothermal fields are successfullybeing worked out. We have created analytical modelsmillion years ago.The data cited on the age of permafrost representan important discovery by Soviet scientists. Wehave to expand the investigations in this directionand give them special emphasis. We have to link theevolution of the permafrost to climatic changes, andfor this we must work in collusion with the climatologists.At the present time a great deal of attention isof the geothermal fields for homogeneous and non- being paid to global climatic change. A warming ofhomogeneous environments in areas with a complex the global climate has been predicted due to therelief. We have also developed methods for inter- accumulation of CO, in the atmosphere. It ispreting geothermal data and the structure from a hypothesized that by 2100 the mean temperature oflimited amount of data.the planet will have risen 2-3' by as compared toFor the first time, either in USSR the or in the present. Such a significant warming of the planetworld, we have carried out complex regime investig- must provoke concern among us geocryologists sinceations of the process of energy exchange in the this undoubtedly would affect the thermophysicalsoil/vegetation/atmosphere system in various perma- conditions of the permafrost materials. We have tofrost and climatic zones. They have made it poss- predict what changes might occur in the permafrostible to describe quantitatively the input-output in the various regions of the country when theyprocesses of hear and moisture exchange between the occur. Will there simply be an increasetheatmosphere and the permafrost, and to establish the temperature of the frozen materials or will theyclimatic conditions for the formation of seasonally start to degrade? The geocryologists in everyand perennially frozen ground. We have achieved a country must.become involved on such predictions.number of results, new in principle, as to theMajor investigations are under way to study thephysics of heat exchange in the snow pack and the laws governing the formation and peculiarities invegetation cover. A new branch of the earth the utilization of groundwater in the permafrostsciences has emerged, namely "thermophysics ofzones. The Permafrost Institute has participatedlandscapes," the basis of which rests on the energy in the compilation of Volume 20 in the monographbalance techniques which allow one to characterize series Gidrogeolopfi SSSR [Hydrogeology of thequantitatively the heat and moisture exchange USSR] which includes three maps: one on geocryobetweenthe individual components of the landscape. logy, one on engineering geology and onehydro-Important investigations have been carried out geology,into the thermophysics of cryogenic phenomena.A multi-disciplinary study of groundwater in theTheories have been developed as to the thermal permafrost zones and the analysis and generalizationabrasion of coasts which will allow us to solve of a vast amount of hydrogeological data accumulateda number of scientific and practical problems as by various organizations have allowed us to achieveto the proper exploitation of the natural resources the mapping of the permafrost hydrology of Easternof coastal areas. Basic principles are being for- Siberia. For the first time in Soviet experiencemulated for predicting thermal abrasion processes, we have compiled for this vast region, with an areaand on this basis, for the first time in the world, in excess of 7 million km3, a map of permafrostwe are working out a universal methodology for pre- hydrology regions at a scale of 1:2,500,000 whichdicting the modification of shorelines of reser- contains a vast amount of information.voirs in the permafrost zone. This research will During the past few years at the Institute weallow us to solve urgent scientific and practical have been developing in a rational fashion geoproblemsassociated with the exploitation of the physical methods for studying the dynamics ofnatural resources of the near-shore zone of arctic physico-chemical processes. By using them one canseas and artificial water bodies.study the regime of changes in the physico-chemicalAs a result of permafrost/geological investiga- composition of the rocks in the upper layers of thetions we have taken cryolithology in a new direc- permafrost during the annual cycle. We have estabtion,focussing on the distribution in the perma- lished that intense physico-chemical processes arefrost of ground ice, depending on the genesis, going on not only in the active layer but also ataccumulation conditions and freezing of the greater depth, down to the zone of zero annualsediments.amplitude.

165The Institute's geochemists have achieved some degrees - of sen5 itivity of the surface to humaninteresting results. They have discovered the activities. Our Institute participates in theeffect of selective adsorption of organic compounds research into and construction of almost all majoron the surface of oxides and of ice. It has been projects in Siberia, the Far East and the Far Northestablished that materials possessing strictly and contributes to the development of recommendadefinedpotentials for ionization are adsorbed from tions concerning rational use of the environmentwater solutions on the surface of oxides and ice. and to the creation of progressive techniques ofA connection has been demonstrated between the construction on permafrost.electron structures of anions and their capability At the present time we have established thefor becoming integrated into the crystal lattice of permafrost conditions obtaining at all the diamondice during the freezing of electrolytic solutions. pipes which are being exploited, at all the tinIt has also been established that the rate of deposits in the Northeast of USSR, the at the coalmigration of salts in frozen sands where no temperaturegradient existsdetermined by the size ofthe charge on the surfaces of the mineral skeletonand of the ice.Geocryological conditions in the alpine regionsof Kazakhstan and Central Asia are being systematic-deposits of Southern Yakutiya and all at bedrockoccurrences of gold and non-ferrous metals.Permafrost investigations extending over a numberof years in the area of the Baykal-Amur Mainlinehave been completed. We have compiled and publishedgeocryological maps at a scale of 1:5,000,000 and aally studied. It has been established that the monograph describing this region; the latterarea of distribution of permafrost in these regions reflects current ideas on the main permafrostamounts to 170,000 km*, which is approximately six characteristics of the northern Amur oblast and oftimes greater than the total area of glacier cover Khabarovsk kray, and of the Baykal and southernin the mountains of Central Asia. Permafrostthickness in unconsolidated materials does notexceed 200 m but in bedrock it reaches 360 m inplaces. The volume of ice included in these frozenYakutiya districts. It has been proven that overa very wide area permafrost is surviving thanks tothe specific nature of the surface cover, ratherthan due to climate. Hence when these areas arematerials amounts to 687 km3. In the northern Tien developed and the surficial insulating cover isShan the lowest areas of permafrost appear atheights of 2500-2700 m above sea level and, indestroyed degradation of the permafrost, with allits negative consequences, is inevitable. Thespecial locations, sometimes even as low as 1800- Permafrost Institute has published predictions as2000 m. In the extreme south of the region, in the to changes in permafrost conditions associated withsouthern Pamirs, the lower boundary of permafrost the development of the eastern part of the BAM zone.occurrence rises to a height 3600-3800 of m.On the basis of these data a permafrost-seismicStudies are under way of the permafrost conditions map was compiled by the Institute of the Earth'sassociated with the formation of glacial mud flows Crust of the Siberian Branch of the Academy ofwhich are a constant threat to many towns in Sciences of the USSR; the data were also widelyCentral Asia and Kazakhstan. A direct connection used by planning organizations in compiling techhasbeen demonstrated between the glacial mud flow nical and working plans for the route of the BAM.activity during the last decade and the retreat of On the basis of fundamental investigations in thethe glaciers which has exposed extremely ice-rich area of engineering geocryology, major applied taskstill masses which, on thawing, are potentialsources of glacial mud flows. The Institute hasrecommended methods of stabilizing the unstablehave been solved with regard to controlling thetemperature regime of foundation materials, theimprovement of agricultural lands and the restoramoraineswith taliks by artificially freezing them. tion of disturbed landscapes. The effectivenessMethods for mapping rock glaciers have been of using a Styrofoam insulating cover to reducedeveloped; data have been gathered on their struc- the depth of thaw in frozen materials has beenture and their rate of movement is being determined. determined. Completion of these investigations hasThe role of rock glaciers in the transport of rock allowed us to begin developing an extremely promdetritusis being assessed. And finally the need ising method for controlling the depth of thaw andto take the movement of rock glaciers into account the ground temperature. This will open the way forduring construction in alpine areas has been more effectively increasing the bearing capacity ofdemonstrated.A major object of permafrost investigations isnazedi (icings); considerable volumes of waterstructural foundations and will considerably increasethe operating safety of foundations.On the basis of long-term multidisciplinaryinvestigations in the North of Western Siberia wehave developed recommendations as to the protectionof landscapes from disturbance and we have proposedaccumulate in icings in the Tien Shan and Pair theduring the cold season. The volume of ice in thelargest naLedi in the alpine areas of Tien the Shanand Pamirs in some years reaches many hundreds of methods for selecting building sites and methodsthousands and even millions of cubic meters. for restoring areas disturbed during the laying ofArtificially increasing the volume of these naZcdi northern gas pipelines. We have compiled ancould be of great practical interest since induced "Interim manual for the protection of landscapesaccelerated melting of these same icings smer in during the laying of gas pipelines in the Far North!'could increase the discharge of the mountain rivers This is essentially the first attempt at a multiduringthe growing season when there is a particu- disciplinary approach to environmental protectionlarly acute need for irrigation water in the foot- in association with land use in the Far North.hills area,We have carried out a large number of appliedInvestigations connected with the protection of investigations directed at solving the Food Program.the environment are being intensified. The first A series of projects have been completed, aimed atmap of the Yakutsk ASSR has been compiled to show optimizing methods of both channel and sprinkler

166irrigation of hay lands and areas of fodder productionin Central Yakutiya. Methods of irrigationregimes have been worked out and recommendationshave been made as to increasing soil fertility.We have been pursuing research into surfacedeformations provoked by the thawing of ground iceas a result of the breaking-in of new arable land.frost materials as an environment for engineeringstructures is of particular interest. This hasarisen from demands for rational use of resourcesand from economic expediency. One means of reducingthe negative impacts of human activities on thenatural environment is the effective use of undergroundchambers. The Permafrost Institute hasIn Central Yakutiya 20-30% of newly broken arable developed a new technology for creating underfieldsbecome uncultivable within 2-3 years due to ground reservoirs in frozen sediments. Thistheformation of the thermokarst trenches up to 1.5 technology is safer, simpler to use and considerto2 m deep along the line of ice wedges. Recom- ably more effective as compared to existing methods.mendations have been made as to the selection of The underground storage chambers in frozen sedimentsareas suitable for cultivation.are designed for storing oil products, water, andMuch attention has been paid to the problems for other purposes. In the agricultural areas ofassociated with using groundwater as a source of Yakutiya they have been effectively used for refrigwater supply. New principles for estimatingerating milk in summer and for farm water supply.reserves of groundwater and new methods for estab- I should like to emphasize the need for geocryo-lishing water-supply installations have been logical studies in the following directions: 1)proposed. Methods of protecting operating water continuation and intensification of studies intowells from freezing have been put into practice, geocryological toprocesses in the permafrost areas;great effect.2) expansion of research into the complex impact ofAlong with ~ukutniproalmag (Yakutsk Diamond natural factors on the freezing and thawing of theProspecting Research Institute) the Permafrost ground and the creation of generalized models ofInstitute has developed a new, progressive type of cryological processes; 3) development of researchfoundation for permafrost areas: reinforced con- into the theory of geocryological prediction, sincecrete piles equipped with built-in refrigeration it is very important to know of changes in permadevicesusing a naturally circulating coolant. frost conditions provoked by human activities andThey are being successfully used in building pro- to develop reliable methods of geocryologicaljects and have led to a considerable reduction in forecasting in order to exclude the possibility oflabor costs, in the cost of building materials, undesirable consequences; 4) expansion and intenandthe overall weight of structures and have in- sification of the scientific fundamentals in termscreased the operating safety of the structures. of methods to protect the environment in permafrostDrilling-and-filling piles are ready to be intro- areas, to which end we must establish reliableduced. Our studies have shown that their bearing criteria for assessing the sensitivity of the landcapacity in permafrost materials is twice that of surface to anthropogenic activities and make recomordinaryprefabricated reinforced concrete piles. mendations as to the rational use of naturalExperimental studies into increasing the efficiency resources; 5) focussing of attention on geocryoofrefrigeration devices and the freezing of foun- logical research on the arctic continental shelfdation materials by means of an insulating cover on in connection with the intensification of prospectthesurface have also been successful. It is recom- ing work in the search for minerals with and theirmended that one use seasonally operating refrigera- impending exploitation; 6) continuation of researchtion devices in building cheap, relatively easily dealing with the construction of oil gas and pipeconstructedearth dams up to 20 m high, with a lines in permafrost areas and the development offrozen, impermeable core, for impounding reservoirs models of the optimal conditions for the laying andfor drinking water and for the purposes of irrigated operation of pipelines with a view to ensuring safeagriculture. The effectiveness and reliability of operation and the maximum economy in terms of consuchstructures has been demonstrated by those struction; 7) improvement of foundation constructionbuilt for the diamond-mining industry.to achieve the most effective foundations in termsLong-term thermophysical investigations by the of both performance and cost.Institute on the dam at the Vilyuy hydropowerSoviet geocryologists are directing their effortsdevelopment have established basic laws governing to the further elaboration of basic problems inheat and mass transfer in the coarse rock material permafrost research and to the solution of practicalof the flanks of the dam and in the fissured bed- problems which are of primary significance in therock of the dam's foundation; the intensity of water development of the northern areas of our country.percolation was also determined. The valuable data Soviet geocryology has achieved major results inaccumulated have been used in planning hydroelectric fundamental and applied research which have perschemesin other permafrost regions.mitted US to assume a leading position in the worldIn view of the accelerating pace of development in this area of scientific knowledge.in the northern regions the problem of using perma-

DRILLING AND OPERATION OF GAS WELLS IN THE PRESENCE OFNATURAL GAS HYDRATESA. I. Gritsenko and Yu. F. MakogonAll-Union Scientific Research InstituteMoscow, USSRof Natural GasNatural gas hydrates have been found to occur widely where reservoirs of hydrocarbonsoccur in permafrost areas. Exploitation of hydrocarbons lying beneath the gas hydrateformations is likely to encounter serious problems, Specifically the heat transmittedfrom the hot drilling mud can result in the decomposition of the gas hydrates adjacentto the drill hole; this results in the release of large volumes of gas which can leadto a violent "gas kick" and the ejection of the drilling mud from the hole. The authordemonstrates how this problem may be overcome by increasing the density of the drillingmud, reduction of its temperature, or by a combination of these techniques.Reserves of natural gas in a solid hydrate state gas hydrates occur include: an abrupt change inLocated on land exceed 1 X lo1' m3, while those be- the specific volume of water and gas during phaseneath the ocean amount to about 1.5 x 10l6 m3changes; the extremely low permeability of gas(Makogon, 1964, 1981; Trofimik et al., 1981; Judge, hydrates and of porous rocks saturated with hy-1981). Fxploitation of the reserves located on land drates: the low thermal conductivity ofthehydrates;requires the solution of some radically new techni- the significant lowering of the strength of rockscal problems. These problems arise from the unique containing hydrates as they decompose; a sharpproperties of gas hydrates which saturate the poreincrease in pore pressure during their compositionspaces of gas bearing strata located in association within a closed system; and an increase in capilwithpermafrost in the sedimentary cover of thelary pressure as the hydrates accumulate in porousearth's crust.rocks. All these properties of gas hydrates dic-The most important of the properties of gas tate to a large extent the technology of drillinghydrates in terms of the peculiarities of exploit- and operating wells in strata where gas hydratesing the deposits of hydrocarbons in areas where theare concentrated.Brief description of the hydrate formationzone and of gas hydrate deposits-24 -10 o 10 20TEMPERATURE, "CFIGURE 1 Conditions of gas hydrate formation.Theoretical calculations, geophysical prospecting,and drilling have revealed the widespreaddistribution of gas hydrate formations and depositsin frozen sedimentary rocks in the earth's crust.The depth of occurrence of the hydrate formationzone is determined by hydrostatic pressure, rocktemperature, composition of the gas and mineralizationof the water in the reservoir. As regardsconditions on land the hydrate formation zoneextends from depths of a few tens of meters to 1-2km. Figure 1 shows the equilibrium curve of hydrateformation for some common gases; Figure 2 presentsa graph of the distribution of the hydrate formationzone for methane, CO,, H,S and natural gaswith a specific gravity of 0.6 depending on thegeothermal gradient. Figure 3 is a map of thedistribution of the hydrate formation zone withinthe USSR (Barkan and Voronov, 1982).Beneath the ocean the hydrate formation zone mayreach thicknesses of several hundred meters,depending on latitude, ocean depth, bottom watertemperature, the geothermal gradient in the sedimentarycover, hydrostatic pressure, composition ofthe gas and mineralization of the water, and in anumber of areas exceeds 2 h. Figure 4 presents anapproximate profile of the hydrate formation zonefor conditions beneath the Beaufort Sea, compiled167

168TEMPERATURE, "CFIGURE 2 Depth intervals of the hydrate formationzones €or some gases in the sedimentary cover ofthe earth's crust.from data provided by Dome Petroleum (Weaver andStewart, 1981) *Gas hydrate deposits, whose distribution may belocal in nature where secondary gas hydrate depositshave formed from free gas deposits duringcyclical changes in rock temperatures, are foundin the hydrate formatipn zone under favorable conditions.Such deposits are usually found beneathpermafrost areas of the continents or beneath youngseas where conditions do not permit the temperatureof the rocks to rise above that of hydrate decomposition,which would result in free gas formation.Initial formation of gas hydrates beneath theocean usually coincides with the upper horizons ofthe sedimentary cover. The upper boundary of suchhydrate deposits may lie a at depth of only a fewtens of centimeters and the lower boundary at depthsof several hundred meters. In some situations gashydrates accumulate in pagoda-shaped masses (Emery,1974; Makogon, 1982).Gas hydrate deposits contain vast reserves ofgas in a solid hydrate form. The problems ofexploiting these gas reserves are not discussed inthe present paper; this is a separate, major topic.At considerable depths beneath the gas hydratethere may be reserves of hydrocarbons at hightemperatures, namely oil, gas and gas condensates.Development of these deep, high temperature hydrocarbonsnecessitates the drilling and operation ofwells which extend through the hydrate zone. Welldrilling and operation in the zone of hydratesaturatedrocks involves a number of specificproblems which originate with the properties ofthe hydrates during the phase transition to waterand gas.FIGURE 3Schematic map of possible hydrate formation (H 2 400 m) in the USSR.

16968 69 71LATITUDE 72FIGURE 4 Approximate profile of methane hydrate formationalong longitude 134-132'W.The hydrates themselves act as a cementing agentin granular rocks which they saturate. With decompositionof the hydrates in some cases the rocks areconverted into high pressure unstable zones.When the phase change from water to hydrate orvice-versa occurs the specific volume varies by26-32%; by contrast, of course the water-ice (orviceversa) phase change involves a change inspecific volume of only 9%.The specific volume associated with the gashydrare(or vice versa) phase change varies by ahundred times. In this situation, if the processof hydrate decomposition occurs in a confined spacethe pressure may increase by several orders ofmagnitude. For example when methane hydrate formsat O'C, and then decomposes due to heating to atemperature of 100°C within a closed cell, themethane pressure increases from 2.6 )Pa to 2500 ma.Well Drilling ProblemsStrata saturated with hydrates are characterizedby extremely low permeability which prevents lossof fluids from the drilling muds by seepage intothe rock and the formation of a protective coatingof clay on the walls of the drill hole. The absenceof a protective film on the walls of the drillhole where one is drilling with high temperaturemuds leads to intense heating of the adjacent rockscontaining the hydrates and to decomposition of thehydrates, The latter phenomenon is accompanied bya marked weakening of the intergranular bonds andthe resultant disintegration of the rocks adjacentto the drillhole. Associated with this extensivecavity development occurs; rock slippages may leadto bits jaming. Discharge of gases under highpressure during decomposition of the hydrates maylead to intense gas kicks and to the ejection ofthe mud from the hole.Where mud temperatures, which in turn are affectedby the hydrostatic pressure in the mud column,are higher than the temperature of hydrate decomposition,intense decomposition will occur,accompanied by the release of large volumes of gas.Figure 5 presents curves which show the relationshipbetween the volume of various gases containedin a unit volume of hydrates under equilibriumconditions. For comparison it also shows curvesof the specific content of gas in a free stateunder identical temperature and pressure conditions.Comparison of the curves presentedreveals that at hydrostatic pressures within thegas hydrates of up to 13.0 MPa (i.e. at depths ofabout 1300 m) the volumes of methane and CO,released due to gas hydrate decomposition significantlyexceed the volumes of gas which could beheld in a free state under similar conditions. Forheavy gases which farm structure II hydrates thecomparable depth is about 550 m. For example inrocks at a depth of 750 m and a temperature of210°C, 1 m3 of pore space filled with methanehydrate will yield 157 nms of gas, while 1 m3 ofpore space filled with free methane will yield 85nm3 ,FIGURE 5 Gas content in a unit volume vs.pressure and temperature in a free andhydrate state for CHq and COz.

170FIGURE 7 Minimum density of drilling mud toprevent decomposition of natural gas (spec.gravity 0.6) hydrate as a function of mudtemperature and depth of hydrate deposit.FIGURE 6 Mud density required to preventmethane hydrate decomposition vs. temperatureand depth of gas-hydrate reserve.The depth at which the volumes of in gas thefree and hydrate states containeda unit volumeof rock are equal is determined by the equation:where: pH = hydrate density in gfcm'Po = atmospheric pressure in MPaT = temperature at depths H and Kz = coefficient of supercompressibilityof the gas in the reservoir conditionsTo = 273.16Ky = mean density of mud in reservoirs ing I cm3Mg = molecular density of hydrate gasn = ratio of water to gas in the hydrates.The intensity of hydrate decomposition and blowoutsof the drilling muds are dictated mainly bythe amount by which the mud temperature exceeds theequilibrium temperature of the hydrates in therocks. Released gases are discharged into thedrillhole, the drilling muds become degassed,lowering their density and resultinga violentmud blowout from the hole. In this situation thepressure of the released gas is dictated by thetemperature at which the hydrates decompose ratherthan by hydrostatic pressure.However a mud blowout is accompanied an by abruptintensification in the process of hydrate decom-position which leads to significant cooling of therock in the area where the decomposition occurs ato a dampening of the decomposition process (theprocess of hydrate decomposition is accompanied byheat absorption to an amount exceeding 400kJ kg perof the hydrate).Intense cavity formation, jamming of drill bits,degassing and blowouts of the mud as a result ofhydrate decomposition may be avoided by increasingthe density of the drilling mud, lowering its temperaturebelow the equilibrium temperature a by combinationof these measures.The appropriate density of the drilling PY mudwhich will eliminate the problem of hydrate decompositionin strata which are being drilled may bedetermined by the equation:102 PpryPy = - g/cm3where Ppty is the equilibrium pressure correspondingto mud temperature tyH is the depth of the gas hydrate depositin metersPp may be determined from the equation:log Pp = 1.415+0.0417(ty+0.01the case of methanetY2) inlog Pp = l-fO.497 (t +0.005ty2) in thecase of natural gas with aspecific gravity of 0.6.Figures 6 and 7 show the curves of drilling muddensities necessary to ensure hydrostatic pressureswhich will exceed the decomposition pressures ofhydrates of methane and of natural gas with aspecific gravity of 0.65, depending on the depthand on the mud temperature.By applying Figures 6 and 7 to the examples ofdrilling into methane hydrate under the following

171conditions:depth of gas hydrate deposit (N) = 500 and1200 m;temperature of gas hydrate = 2" and 18°C;Under certain conditions the gas pressure proequilibriumtemperature t = 6.5' and 19'C;voked by hydrate decomposition in a closed cavernhydrostatic pressure in tRe hydrate Ph = 5 and12 MPa;around a drillhole may considerably exceed the rockpressure and may result in the collapse of theand mud temperature ty = O", 5", lo", 15' and drillhole with all the resulting consequences.2O0C;Increases in pressure and temperature follow theequilibrium curve to the point where the hydrateswe can determine the density of the drilling mud are either totally decomposed or where the stressnecessary to prevent hydrate decomposition.In the case of the upper hydrate deposit whereproduced in the surrounding rock and in the sidesof the drillhole reaches a critical value andtY = Oo, 5", lo", 15" and 20°C equilibrium pressures failure occurs.wlll be 2.6, 4.5, 7.5, 13.0 and 23 MPa respectively. Figure 8 presents curves of the relationshipThe mud density necessary to prevent decomposition between pressure and gas temperatures associatedof the hydrates will be 0.52, 0.9, 1.5, 2.6 and with decomposition of methane hydrate in a confined4.6 g/cm3 respectively. As can be seen from the space, with various levels of dynamic collapse ofvalues just quoted if the mud temperature is main- that space in which the hydrare decomposition istained between 0' and 5°C this will totally elim- occurring.inate hydrate decomposition in the reservoir andPrevention of the collapse of drillholes beingwill ensure safe drilling conditions. If the mud operated through hydrate-saturated rocks be maytemperature is maintained between 10' and 15'C it achieved by reinforcing the well, by using casingis necessary to increase its density to 1.5 to 2.6 with a high thermal resistivity through the hydrateg/cm$; and at a mud temperature of 20'C it isdeposit which would eliminate the heating of theeffectively impossible to prevent hydrate decom- adjacent rocks above the equilibrium temperature ofposition by increasing the mud density (a muddensity of at least 4.6 g/cm3 would be necessary).One can ensure normal, trouble-free drilling inthis latter situation by using a combination oftechniques, namely by lowering the mud temperatureto 12.5'C and by increasing its density to 2 g/cm3.In addition I would recommend a closed system ofdrilling whereby high wellhead pressures are maintained.For example when Py = 2 g/cm3 and tY =20°C it is necessary to maintain a wellhead pressureof 36 "a, although this will greatly complicatethe drilling operation.In the case of a gas hydrate deposit lying a atdepth of 1200 m and with mud temperatures of 0".5", lo", 15" and 20°C the equilibrium pressure willbe similar to those of the upper part of thedeposit (with identical gas composition) i.e. 2.6,4.5, 7.5, 13,O and 23 MPa. The mud pressure necessaryto prevent hydrate decomposition will 0.22, be0.38, 0.63, 1.1 and 1.92 g/cm3 respectively.Where one is estimating permissible temperaturesand the requisite densities of drilling mud fordrilling in gas hydrates one has to know the compositionof the hydrate-forming gas and the equilibriumvalues for pressure and temperature. Ineach specific case, on the basis of technologicallimitations and economic considerations, one canthen recommend certain values for the density andtemperature of the drilling mud.Problems Arising During Well Operationdrillhole heat up, the decomposition will occur ina closed cell. It is well known that hydrate decompositionis accompanied by an abrupt increase inpressure (Makogon, 1964).the hydrate, by using either active or passiveinsulation techniques. In some cases the necessaryeffect may be achieved by lowering the temperatureof the mud at the well bottom.During the exploitation of high-temperature oilor gas deposits located beneath a gas hydrate depositthe rocks surrounding drill holes heat up.If the temperature in the hydrate deposit risesabove the equilibrium temperature, decompositionof the hydrate occurs, whereby the hydrate changes0 50 leu.TEMPERATURE, OCphase to free gas and the ice into water. If thehydrate deposits are confined top and bottom FIGURE 8 Pressure vs. gas temperature duringbetween impermeable strata and the rocks are highly methane hydrate decomposition In a limitedsaturated with hydrates, when the rocks near the volume.

172REFERENCESBarkan, E.S. and Voronov, A.N., 1982, Zones ofpossible hydrate formation on U.S.S.R. territory:Sovetskaia geologiia, no. 7, p. 37-41.Emery, K.O., 1974, Pagoda structure in marine sediments,g Marine Science, v. 3: N.Y. PlenumPress.Judge, A., 1981, Natural gas hydrates in Canada,- in Proceedings of the 4th Canadian PermafrostConference, Calgary: Ottawa, Ont., National ResearchCouncil of Canada, 1982, p. 320-328.Makogon, Yu.F., 1964, Hydrates of natural gases:MOSCOW, Nedra; (English transl.) L.C. no.M880.M3213: Tulsa, Okla., Penn Well PublishingCo., 237 p.Makogon, Yu.F., 1981, Perspectives for the developmentof gas hydrate deposits, & Proceedings ofthe 4th Canadian Permafrost Conference, Calgary:Ottawa, Ont,, National Research Council ofCanada, 1982, p. 299-304.Makogon, Yu.F., 1982, Drilling of wells opening gashydrate layers: Gazovaia promyshlennost', no. 4,p. 30-32.Trofimuk, A.A., Makogon, Yu.F. and Tolkachev, M.V.,1981, Gas hydrate deposits - a new source ofenergy: Geologiia nefti i gaza, no. 10, p. 15-21.Trofimuk, A.A., Makogon, Yu.F. and Tolkachev, M.V.,1983, Role of gas hydrates in processes of hydrocarbonaccumulation and formation of their deposits:Geologiia 1 geofizika, no. 5, p. 3-15,Weaver, J.S. and Stewart, J,M., 1981, In situhydrates under the Beaufort Sea Shelf, Proceedingsof the 4th Canadian Permafrost Conference,Calgary: Ottawa, Ont., National ResearchCouncil of Canada, 1982, p. 312-319.

THE IMPACT OF INSTALLATIONS FOB THE EXTRACTION AND TRANSPORT OF GAS ONPERMAFROST CONDITIONS IN WESTERN SIBERIA AND COMPREHENSIVE ENGINEERINGGEOLOGY FORECASTING OF RESULTANT CHANGESYu. F. Zakharov, L. D. Kosukhin, and Ye. M. NanivskiyMinistry of the Gas IndustryTyumen', USSRThe bulk of the installations associated with the extraction and transport of naturalgas represent ma jor, constant sources of heat emission. The gas fields now beingdeveloped in nor thern West Siberia are in areas of ice-rich sediments such that settlementon thawing would greatly exceed.acceptable limits. Hence the need for predictionof the possible interaction between a variety of Structures built using varioustechniques and the underlying frozen sediments is paramount. The article outlinesthe steps in developing such a forecasting model with a view to selecting the optimumdesign €or gas field structures and to developing an effective program of monitoringof their performance.The development of the gas fields of Western Western Siberia the ice content of the permafrostSiberia has been accompanied a by wide range of materials is such that settlement on thawing wouldintensive mechanical, hydrostatic, thermal,considerably exceed acceptable limits in the casechemical, electrical and orher forms of Operations of the overwhelming majority of the gas productionon frozen, thawing and freezing materials. The installations. This has led to widespread use oftypes of operations listed lead to severe and preliminary thawing of the frozen sediments, andirreversible man-induced changes in the geobotanical ubiquitous use of pile foundations and gravel padsenvironment, some of which may be anticipated in during construction on the gas fields. Thus conplanningdecisions, but many of which have turned struction and operation of the installationsout to be unforeseeable. Evaluation of changes in associated with gas extraction and transport simulthegeological environment, and especially in taneously lead to fundamental changes in the hydropermafrostconditions, represents the basis for geological, geodynamic and geochemical conditions,selecting design options in terms of engineering the parameters of which depend entirely on thepreparation of a site, minimizing temperature geological and geocryological peculiarities of theoscillations, and the choice of many aspects of gas-bearing region.design and technological aspects of buildings, Present designs of installations for extractioninstallations and communications, and even interms of plans for exploitation of the gas deposits.An essential element in the evaluation of changesin the permafrost environment is long-term quantitativeprediction of such changes. Interactionsbetween the producing installations associated withgas extraction and distribution and the geologicalenvironment occur at many levels; moreover they maypredicting and taking into account at the planningstages changes in all elements of the geologicalconditions, without exception. The omission oroccur only once, or may be ongoing. As a result it underestimation of any change, even in an apparentlyis extremely difficult to isolate the results of secondary element, may lead to the prediction beingeach impact, its component parts, and the geological less reliable and to its being ignored during theprocesses which it provokes. It is equally diffi- design process. Hence the design for the construccultto make specific forecasts, either general or tion and operation of gas fields in the permafrostlocal, of these impacts and processes, taken zone must rest on the basis of comprehensive enginseparately.But without such specific forecasts, eering and geological forecasts. Kost importantlygeneral or local, it is impossible to achieve com- the gas field design must be seen a single asplex predictions of the consequences of the aggre- dynamic system, which we may refer to as a geogateof all the interactions between the gas technical system. Such a system possesses a wholeindustry and the geological environment during the range of specific and latent properties whichdesign stage for gas field operations.effectively combine to reflect the entire aggregateThe overwhelming majority of structures associ- of interactions (on various timescales and atated with gas extraction and transport represent various levels) between the geological environmentmajor and constant sources of heat emission, andhence critically alter the thermal balance of thegeological environment, leading to significantthawing of the permafrost materials and to loss ofbearing strength.Throughout the gas fields now being developed inand transport of gas on frozen, thawing and freezingsediments which take into account only their thermaland mechanical interactions are inadequate. It ispossible to increase the reliability of gas producingand gas transport systems by identifying,and the production facilities of the gas industryduring the entire designed lifetime of the gas field.For the purpose of comprehensive engineeringgeologicalpredictions the functioning of thisgeotechnical system must be examined as an aggregateof various ongoing changes in the geological envir-173

174OnmenK along with, in particular detail, all the geotechnical system. The methodological basis forelements of the original engineering-geological predicting changes in conditions affecting theconditions existing at the time when the design engineering geology is the comparative geologicalfor the operation of the gas field was first for- approach based on analysis of formations, faciesmulated. During the process of this examination it and paleogeographical and paleo-geomorphologicalis essential to obtain and analyze various of types conditions and on other methods of studying theinf0n”KiOn and, on the basis of an acceptable geological environment, and based on constant andscheme for extraction, and of acceptable recoverable widespread use of spatial and time analogs. Inreserves of gas and gas condensates, to carry out studying the elements of the engineering-geologythe necessary predictive calculations of the follow- conditions and the technology of the gas industrying parameters: 1) the drop in reservoir pressures a qualitative and quantitative evaluation is madeand dehydration of the strata being exploited; 2) of the parameters of both aspects with view a toextraction of mineral particles from the producing determining the limits of possible acceptable andstrata along with the gas, condensates and water; optimal changes in both. Special attention is paid3) compaction of the producing strata; 4) warping to studying the mobility and stability of linksof the overlying strata; 5) surface subsidence; betwe,en elements and to the identification of the6) raising of the groundwater table to due surface roles of individual factors affecting those elementssubsidence and development of the field; 7) accumu- The study proceeds by identifying the character andlation of surface drainage in depressions due to form of the functional relationship between thesurface subsidence; 8) changes in the temperature, obligatory structures of geotechnical functions.nature and properties of the surface sediments due At the same time studies also focus on the capacitto waterlogging and changes in other engineering- for resisting the altered engineering geology congeologicalprocesses; 9) changes in any otherditions and restoration of the equilibrium, upsetelements in the engineering-geology conditions due as a result of human activities. One of the tasksto the planned construction and to disruptive human of planning investigations is to establish theactivities in terms of the specific planned instal- symptoms for the changes occurring in the engineeringgeology conditions and any portents of criticallations for gas extraction and transport.The complexity of such forecasts is further paramerers in order to provide a monitoring servicincreased by the need to take into consideration to engineering geologists which will give accuratescientific and technical advances in the gasand reliable signals and diagnostic signs of theindustry which are not yet common property and have onset of any developing defects or failures innot been included in operational designs but have installations associated with gas extraction andalready proved their effectiveness in industrial distribution. All information on engineeringexperiments, and hence can and must be brought into geology conditions and on changes in those conoperationaluse during the designed lifetime of the ditions, correlated with potential planninggas field. In addition to those parameters derived decisions re development and construction of a gasby the process of traditional engineering explora- field, is examined from the point of view of systemstion, the attainment of such long-term, comprehen- and factor analysis during the process of compresivequantitative engineering geology forecasts hensive engineering geology predictions.demands the identification and evaluation of aThe algorithm of such predictions may be dividedwhole range of parameters concerning geological into seven steps, each of which may in turn beconditions: 1) the coefficient of linear tempera- divided into a number of stages. Comprehensiveture-related deformation of mineral and organic engineering geology predictions begin with thesoils and peat; 2) maximum sustained strength of following: 1) a scientific hypothesis as tothe frozen materials; 3) coefficients of thermal possible changes in engineering geology conditionsconductivity and apparent electrical resistivity of and the consequences associated with the implemenfrozenand thawed materials; 4) specific electrical tation of specific activities during the developmentconductivity and dielectrical penetrability of of gas resources in a specific area; 2) the creationfrozen and thawed materials; 5) thixotropic and of a working hypothesis, a plan for the operationrheological properties of thawed materials; 6 ) the the designed geotechnical system, and a sequence ofphase composition of H,O in the materials at various geological processes in association with implementemperatures;7) composition of organic materials, tation of potential design decisions.soluble salts and exchangeable cations in thawed The second step involves the process of studyingmaterials; 8) content of ferrous oxides, aluminum the structure and clarifying the limits of the geotechnicalsystem being forecast and the testing ofoxides, oxides and protoxides of iron, amorphousacids and carbonates in thawing sediments; 9)the working hypothesis as to how it functions. Thiscapillary vacuum, capillary moisture capacity, water stage ends with the translation of the hypothesesloss and the coefficient of filtration anisotropy into a conceptual, graphic information model of tin thawing and freezing materials; 10) flow linesin bog water, and other parameters.To provide comprehensive engineering geologypredictions using both traditional sources andthese additional sources of information it isessential to carry out comprehensive long-termgeological investigations at many levels, Thefocus, content, time frame and scale of theseinvestigations can be determined by using a flowchart of objectives, closely related to a geodynamicmodel of the functioning of a predictivesystem and the execution of a qualitative comprehensiveforecast.On the basis of such prediction, a program ofinvestigations, experiments and of practical andanalog modelling is implemented; a geodynamiccause-and-effect model of the functioning of thegeotechnical system with all the anticipatedvariants is built and a corresponding computerprogram is created. The geodynamic model representsa hierarchical system of models: imitative andoptimizational, balanced and dynamic, graphic and

175matrix-type, reflecting the structure of the system in different landscapes, of the formation, distribubeingmodelled and its interrelations with other tion and melting of the snow cover, and of a widesystems, and describing the interaction of instal- spectrum of climatic parameters in order to identifylations for the extraction and distribution of gas the extremes and annual mean values.with frozen, thawing and freezing sediments and all The operations listed above comprise the thirdthe other components of the geological environment. and fourth steps in comprehensive forecasting. AtThe analytical expression of such a system of models the same rime one has to undertake an analysis ofis synthesized by a number of determined, stochastic, the current state and trends in the development ofeuristic and dialogic algorithms and is aimed at the gas industry and of the associated branches ofachieving a predictive evaluation of the develop- construction and of the economy. In the case ofment and operation of the gas field.long-range forecasting it is essential to take intoThe geocryological components of such a model consideration social/political factors which nor areinclude the possible, anticipated and inevitable conducive to easy prediction but which have anquantitative changes in temperature, ice content of impact both on the entire process of operating thethe sediments, depth of seasonal freezing and thaw- geotechnical system and on the development of itsing, and the cryogenic processes (rhermokarst, individual elements. In the first instance it isfrost-heave, frost cracking, thermal erosion, necessary to predict specific policies of statesolifluction, naZed (icing) formation, etc.) which limitations on utilization of the environment,develop in association with well drilling or with allocation of resources, and on rigorous applicatheerection and operation of buildings, installa- tion of the norms for environmental protection.tions and communications, in association with re- Such predictions of the development of the technopairand maintenance work, or in association with logical environment represent the fifth step invarious forms of economic or non-productive human comprehensive engineering-geology forecasting.activities in the cryolithozone of Western Siberia. The penultimate step involves morphologicalThe incompleteness of our knowledge as to the nature analysis of the data, utilization of techniques ofof complex thermophysical processes and of heat and "matrix interaction" (which the authors of themass exchange in sediments in association with their method, Gordon and Helmer (1969) consider to be "ainteraction with heat-emitting installations does method of analysis which allows systematic investinotallow us to formulate adequately the dynamics gation of the results of the potential interactionor the results of cryogenic processes in mathema- of elements in an aggregate of events"), organizaticalexpressions. Analytical relationships used tion of the data in a form suitable for computerat present describe these processes only very and graphic handling, analysis of the comprehensivesketchily and require a large number of assumptions qualitative forecast and a synthesis of specific andand considerable generalization of the information local forecasts into a unified forecast, and finallybeing predicted. Hence it is impossible to make the predictive calculations themselves. The seventhgeocryological predictions without field studies of and concluding step in a comprehensive engineeringthedynamics of heat and moisture exchange and the geology forecast encompasses forecasting expertise,changes they provoke in the sediments, in order to the development of recommendations as to its applicobtainmany numerical parameters in predicting the ation, and also the injection of the results intointeraction of specific planned installations for planning any engineering-geology monitoring of thethe extraction and distribution of gas with frozen, geotechnical system for which the forecast is beingthawing and freezing sediments. Owing to theprepared.exceptionally high mobility of the elements of the For comprehensive engineering geology purposesgeocryological component in the model, evaluation three types of methods of scientific-technicalof the magnitude of the changes occurring when one prediction may be applied: that of technical inbuildsand operates gas field installations a is dicators and expert evaluation; extrapolation andlabor-consuming task which can be handled only by analogy; and modelling, whether analytical analog.means of a prolonged program of regular observa- or natural. Analytical methods are the most widelytions at various levels and by large-scale field used, both in constructing the geodynamic model andexperiments. These investigations are carried out in the predictions themselves. They are based onin both artificial and natural sediments and also calculations selected from geomechanics, geodynamics,in materials lying beneath covers, installations, hydrodynamics, thermodynamics, whether applied ingravel pads, soil or vegetation covers and under that sequence or concurrently, which occur in thepeat accumulations. A study of the dynamics of course of man-induced changes in engineering geologyseasonal freeze-thaw in sediments of and theconditions. The procedures of comprehensive enginpeculiaritiesof the details of their temperature eering geology prediction consist of multi-stepregime is carried out under natural conditions and integration of the selected schemes of calculationwhere the conditions have been disturbed by man, which make up the aggregate of discrete and differandalso during the course of the associated cryo- ential equations in a single forecast, based ongenic processes as they occur, namely frost heave, such cybernetic methods of prediction as the consolifluction,thermokarst, frost cracking, naled struction of predictive flow diagrams, morphological(icing) formation, thermal erosion, etc. In the analysis and "matrices of interconnections."process evaluations are made of the impact on theThe results of comprehensive engineering geologynature and magnitude of such processes of soil, forecasting may be stated in four ways: graphicvegetationand artificial coverings and of engin- ally, in tabular form, verbally, or cartographiceeringoperations associated with planned instal- ally. The most effective method of presenting alations for the extraction and distribution of gas. forecast is as a scenario. I have suggested pre-At the same time detailed observations must be made senting a forecast in the form of such a scenarioof the heat balance of the atmosphere/soil system where the results of the forecast are expressed

176along with the technology for implementing the compile technical designs for the operation andaccepted design solutions and with the development building of gas pipelines, and also formulate aplans for the technical components of the system. program for engineering-geology monitoring of theOn being compared with the characteristics ofoperation of gas extraction and distributiondevelopment of the technical components, the results systems.of the forecast are translated into a dynamic means One may ensure the reliability of installationsof determining the most effective possibilities for for the extraction and distribution of gas oneliminaring the negative consequences of intense frozen, thawing and freezing sediments by means of:human activities in the area of environmental1) changes in the content and technology of designs,modification in the permafrost zone, Using Chis whereby nor only the technical designs of indivscenarioone can easily formulate alternarive idual installations and communications must bevariants of the forecast, constrained by non- the developed, but also integrated designs for entiresimultaneity of the intended design solutions at geotechnical systems (gas well installations; mainthe early stages of planning and the ambiguity of gas pipelines, etc.) on the basis of comprehensivethe forecast data.engineering-geology forecasts; 2) purposeful andOn the basis of the results of both specific and effective operation of such systems; 3) and engingeneralgeocryological forecasts and of comprehen- eering-geology monitoring of the building andsive engineering-geology forecasts one may specify operation of such systems.the technical design for exploiting gas fields,

ENGINEERING GEOCRYOLOGY IN THE USSR:A REVIEWS. S. Vyalov*Research Institute of Foundations and Underground StructuresMoscow, USSRIn this review of engineering strategies in permafrost areas the author stresses thatin view of the rapidly expanding scale of developments in the North, the engineercommonly is unable to select the most favorable site, in of terms permafrost conditionsand hence must be prepared to deal with any permafrost conditions. From this premisethe article proceeds to a study of building techniques involving either the preservationof permafrost or its elimination. In each case a variety of techniques andexamples of their adoption are presented, along with a discussion of methods of calculationof the forces and bearing capacities involved. Examples of the more innovativetechniques discussed are the use of artificially refrigerated piles in the case oftechniques aimed at preserving the permafrost, and the use of localized prior thawing,specifically around the supporting piles, in an of area "warm" permafrost with a highice content.Engineering geocryology, as an applied branch ofthe science of geocryology, arose in response topractical needs, especially in connection with thebuilding of the Transsiberian Railway in the latenineteenth-early twentieth centuries. In itsmodern form engineering geocryology embraces thestudy of the interactions between various types ofengineering structures and permafrost, whether inthe role of foundation, environment or buildingmaterial, and also the developmenr of methods forcontrolling these interactions. The theoreticalfundamentals of engineering geocryology are thephysics, thermophysics and mechanics ofrozen (ormore accurately frozen, freezing and thawing)sediments. The physics of frozen sediments examinesthe physical and chemical relationships betweenprocesses operating within the sediments are incontestable.In fact temperature is one of the mainfactors determining both the mechanical propertiesof frozen ground and its behavior under load. Butthe temperature regime of frozen ground experiencesconstant change both as a result of changes in airtemperature and as a result of the thermal impact ofinstallations. The properties of the ground willaccordingly change with time and these changes canbe identified only by examining the thermal andmechanical processes together.It is evident that an integrated examination ofthis type can best be effected on the basis of thethermodynamics of irreversible processes inasmuchit is precisely the thermodynamic equations thatembrace expenditures of both thermal and mechanicalthe sediments as a multi-component system andenergy. At the same time equations of thermostudiesthe mechanics of the freeze-thaw processes, dynamics derive from phenomenological relationshipsThermophysics embraces the conditions of heat and without examining the physical essentials. Hence,mass exchange in the system comprising environment! with a view to achieving greater generalization itstructurefground and describes the process mathe- is convenient to produce baseline laws governingmatically. Mechanics examines the laws governing the deformation and destruction of frozen materialsthe behavior of €rozen/freezing/thawing sediments on the basis of examining physical concepts perunderload and establishes the relationships, taining to the mechanics of the process. Such anexpressed mathematically, between stress, strain, attempt has been made by the author (Vyalov 1978a)temperature and time. Inclusion of the time factor and by others. On the basis of an experimentalis dictated by the fact that the processes of the study of the microprocesses occurring in theimpact of heat and load on the sediments change materials during deformation and protracted deswithtime, while the frozen ground itself possesses truction, peculiarities and laws governing changesclearly expressed rheological properties (creep and in the structure were identified, The changeslong-term strength); accordingly its stress-strain included the displacement and reorientation ofcondition changes with time. Hence the modernparticles and the development of structural faults,mechanics of frozen ground is based on the theory while on the basis of kinetic theory they wereof rheology.considered to be thermally activated processes. ByEach of the abovernentioned aspects of engineer- using Boltzmann's equation, which relates theing geocryology has become quite well developed and displacement of particles to the activating force,has attained a number of major achievements. But a strain equation was derived which established thethe development of each aspect has proceeded autono- relationship between the strain rate and itsmously without proper consideration of the inter- magnitude and the stress, temperature and time.dependences which exist, although the connections With certain simplifications this equation may bebetween the physical, therrnophysical and mechanical converted into the well-known phenomenological*Not present; summary presented by N.A. Grave.177

178exponential equation of deformation, although withphysical parameters.On the basis of laws governing the accumulationof structural defects revealed by micro-structuralinvestigations, an equation of long-term failurewas derived and was subsequently generalized onthe basis of thermodynamics. It was assumed thatground failure begins when the influx of entropyreaches some critical value dependent on reachingsome degree of structural damage to the ground(intensity of accumulation of faults). As a resulta physically based equation of long-term strengthwas derived which relates the magnitude of thestate (Principle l), or whether they are allowed tothaw (Principle 2). This distinction appearedspontaneously during the early period of constructionon permafrost and was incorporated in theBuiZding Standards and Rules fur Design uf Foundationson Permafrost (1976) and the Manu2 for thesestandards (19781, both of which apply throughoutthe USSR. In the following discussion I shallexamine the use of permafrost materials a as foundationfor buildings and installationsaccordancewith the above-mentioned documents.In the case of construction based on Principle1, the main problem is to maintain the sediments indestructive load to the time to failure and to the a frozen state throughout the operating life of ttemperature.structure. The simplest way involves building aThe resultant equations of strain and long-term naturally ventilated foundation. This method hasfailure, based on physics, allow one to make calcu- been used by Russian engineers since early in thelations as to strain and strength in frozen ground century and was described by Stotsenko (1912). Theat any given moment; this includes predictions for theoretical basis of the method was presented inthe entire operating life of the installation. The the 30's by N, A. Tsitovich. The first major conabove-mentionedequations allow one to take into crete building to use this method was a thermalaccount the variability in time of both thermal and power station built in Yakutsk in 30's; the it isforce components,still operating quite successfully.In discussing the simultaneous examination ofSubsequently the method of construction wherebyboth thermal and force components one may note the the permafrost is preserved has been widely adopted,following. At the present time the thermophysical especially in the northern areas of permafrostand mechanical problems are being solved separately, occurrence. The buildings in cities such asand in the solution of the mechanical problems Yakutsk, Mirnyy, Noril'sk, etc. have all been builtparameters determined by the solution of the ther- using this method.mophysical problems on the same site are being The method of construction whereby the permasubstitutedin solving the mechanical problems. frost is first thawed also emerged early thisThus the mechanical state of materials is being century, with reference to construction in thedetermined on the basis of some field temperature southern areas of permafrost occurrence, in cities(e.g. the annual maximum temperature). Howeversuch as Chita, Petrovsk-Zabaykal'skiy, etc. Theground temperatures vary with time, both a as main problem connected with the use of this methodresult of variations in air temperature and a as was to prevent major damage to buildings a result asresult of the thermal impact of the installation. of ground settlement during thawing. Hence theMechanical processes in the materials (creep, long- buildings were reinforced with rigid girders, strapsterm strength changes) are also proceeding with etc. and attempts were made to select buildingtime. Hence it is essential to be able to describe sites where thaw settlement of the ground would bethe synchronous operation of these processes. minimal.Unfortunately such a combined equation has not yet But in recent years, in the light of the largebeen achieved. But once one has solved thetheoretical thermophysical equation (and this hasscale of the operations, conditions affectingconstruction in the North have become substantiallybeen achieved both in the USSR, by G. V. Porkhayev more complicated. In the North we have begun toet al. and abroad) it is possible to regard this build multi-storey (9-12 storey) buildings, tosolution as the starting point for solving the erect industrial installations with large spans andmechanical problem. However to do this it ishence with heavy foundation loadings. Hence thenecessary to derive the strain and long-termneed for strength and durability in these structuresstrength equations with parameters which with vary has increased proportionally, yet on the other handtime and which determine the dependence of the the need for economic effectiveness has also inmechanicalprocess on temperature. As mentioned creased. But the main thing is that nowadays weearlier the author has achieved these solutions; cannot select the most favorable site in of termsthey can also take into consideration a load which the permafrost conditions. We have to build onvaries with time.sites dictated by the needs of technology or design;It is extremely important to take the above- this is especially important in terms of buildingmentioned circumstances into account in makingtransport installations (railroads, highways, pipepracticalcalculations, as will be demonstrated lines, electricity transmission lines, etc.). Hencefurther.one has to be able to with deal any permafrostconditions, including the least favorable conditions.Control of the Interactions betweenIn particular, in terms of construction in areasStructures and Permafrostnear the southern limits of permafrost one invariablyencounters plastic-frozen "warm" permafrostThe marked differences in the properties and sediments (very close to O"C>, which at the samebehavior under load of sediments in the frozen and time possess very high ice contents. In many cases,thawed states have dictated that one identify two in addition, the permafrost here is discontinuousseparate principles for using these sediments in in terms of both vertical and horizontal distributermsof their interaction with structures, i.e. tion. It has also become necessary to build onwhether the sediments axe maintained in the frozen sites with massive ground ice bodies, whereas

1 19previously such sites were generally avoided, andalso on mineralized frozen ground, whose bearingstrength is sharply reduced, but whose susceptibilityto deformation is increased, on and frozenpeat deposits. Finally, we have had to build onpermafrost in areas with high seismicity.All of this has called for new a approach toconstruction on permafrost. While earlier weattempted to adapt our construction techniques tothe behavior of the permafrost this method is nowfound to be ineffective. In fact we are now everywhereencountering situations where due to permafrostconditions ("warm" permafrost with an unstableregime) or due to technological or constructionpeculiarities of the structure (large spans, heavyloadings on the floor, or a "wet" technologicalprocess) it is difficult to maintain the sedimentsbuildings have been built using this method, conina frozen state by the simplest methods (i.e. the struction has begun on the headquarters of thenormal ventilated foundation), and where it is building industry, a structure whose main floorimpossible to allow the sediments to thaw while the area occupies 160x 200 m. It turned out to bestructure is in use, since this would lead toimpossible to provide natural ventilation to theserious settlement, which would be inadmissible subfloor of such a structure and hence they hadeven if the structure were reinforced. Hencerecourse to building a system of air extractioninstead of adapting the construction techniques shafts inside the building, along its centralto the behavior of the permafrost beneath the longitudinal axis. In other cases (garages, etc.)structure by one means or another, we to have pro- the supply of cold air to the sub-foundation sedividethe frozen materials with specific geotechnical ments is achieved by using ventilation ducts placedproperties which will ensure the conditions neces- in a sand-and-gravel pad beneath the floor, eithersary for the operation of the installation. In extending below the entire building or just adjacentother words it is essential to be able to control to the foundations. This method has been usedthe interaction of the permafrost and the structure effectively (both in the USSR and abroad) for quiteerected upon it.a long time. More promising in the long term is aWhere one uses the technique of preserving the new method of refrigerating the ground using hollowsediments in the frozen state, control of those ventilated foundations. They are constructed in theproperties is achieved by regulating the thermal form of hollow, corrugated pallets and are on laidregime of the foundation materials and especially sand-and-gravel pads beneath the floor of the buildbyeffecting supplemental refrigeration where these ing, whereby the cold external air circulatessediments are "warm" plastic-frozen materials. The through the hollow ducts of this foundation (Figurecooling is usually achieved by means of the external I). Hence these foundations combine the functionswinter air, i.e. by utilizing the severity of thenorthern climate. The principle on which thismethod is based involved the difference in meanannual temperature between the air and the frozenground, the air temperature being a few degreeslower. For example, cooling of the ground from-0.5"C to -2.5"C will triple its strength.Where materials in the thawing condition areutilized, control of the properties involves regulatingthe thaw regime. Once the structure is inoperation unregulated thawing is permitted only inrare cases where the permafrost materials possessonly a low ice content and hence the settlement onthawing will be only minor. But in the majority ofcases one encounters ice-rich materials which resultin drastic subsidence on thawing, If one uses thethawing technique in this situation one can reducethe magnitude and variability of the subsidence bymeans of prior thawing of the sub-foundation sedi-ments, in which case the bulk of the settlementwill have occurred prior to erection of the structure.One should note that in order to control theforces involved in frost heave, which affectsfoundations during seasonal freezing of the ground,physical-chemical methods have been used quitesuccessfully; in particular, treatment of thesurfaces of the foundations or of the sedimentsthemselves with special greases and additives.Design formula derived on the basis of the ideaspresented above were presented by the author in areview article at the Third International Conferenceon Permafrost (Vyalov 1979). Here I shalldiscuss examples of construction where these techniqueshave been applied.Construction with Preservation of thePermafrostThe traditional method of preserving the permafrostby means of a naturally ventilated subfloor(which represents the simplest technique of controllingthe temperature regime) is quite efficientwhen the sediments are solidly frozen (i.e. verycold) and where the building is not very wide. Butright now in Yakutsk, where almost all the modernXXtI I I 1FIGURE 1 Corrugated ventilated foundations combiningche functions of a load bearing mit and arefrigeration device.

180of both load-bearing design and a of coolingdevice.One should note that while in the of casesolidly frozen "cold" permafrost it is sufficientjust to maintain its natural temperature, in thecase of plastic-frozen "warm" permafrost is it nec-used for this. They include clearance of snowfrom the building site prior to the start of conessaryto lower its temperature in order to convert struction, the blowing of cold air into holesthe sediments from the plastic-frozen to the solidly drilled for subsequent emplacement of piles, andfrozen condition. Accordingly, when making thermal- the refrigeration of those piles with CO,. But thetechnological calculations of the system embracing use of thermal piles is particularly effective.a building and its foundations the required tempera- In the Soviet Union use has been made of thermalture of the foundation is predetermined and on thebasis of that temperature the construction andpiles, both with a liquid cooling agent-namelykerosene (this type of pile was first proposed bythermal regime for the operation of the subfloor is the Leningrad engineer, S. I. Gapeyev) and with adictated. The method of calculation developed by gaslliquid cooling agent-namely freon. In someG. V. Porkhayev is specified in the Standards and in cases the thermal piles are built into the structurthe associated MaanuaZ. A similar approach is also of the foundation. This method, i.e. installationused for cooling frozen sediments using ventilated of reinforced concrete piles with liquid refrigeraducts,hollow foundations, etc,ting devices (thermal siphons) built into them, wasIt has been demonstrated in practice that by used in the construction of nine-story buildingsusing various cooling devices, including ventilated in one of the subdivisions of Mirnyy at the sugsubfloors,it is possible to lower the mean annual gestion of the Permafrost Institute of the Academytemperature of sub-foundation permafrost by several of Sciences of the USSR. A paper presented bydegrees. But it will take several years (1-3) after Mel'nikov (1979) at the Third International Permaerectionof the structure to achieve this lowering frost Conference was devoted to this topic.of the temperature. Hence in calculating the bearingstrength of a foundation this lowering ofIn other cases the thermal piles are installedindependently of the foundation and operate simplytemperature cannot be taken into account and enters as cooling devices. This type of thermal pilethe calculations only as a safety margin. In order (using freon as a cooling agent) has been widelythat the bearing strength of the foundation has been used in Vorkuta in particular. The practical-e+naxntadequately increased by the time the full load ofthe structure has been placed upon it, it is necessaryto lower the temperature of the ground priorto or during construction. Various methods areproblems of using thermal piles in the North, theirdesign and methods of relevatn calculations are consideredin Vyalov (1983) and in Buchko et al. (1978).Taking into Account Variations inTemperature and LoadingIn examining the problem of regulating thetemperature regime of foundations in permafrost itP * constis necessary to proceed from the following statements.In general the temperature regime of the refrigpk I = I +erated sediments is dictated by the initial coolingprior to construction, cooling during the course ofoperation of the building by means of a ventilatedcrawlspace (or ducts) and additional cooling bymeans of special devices such as thermal piles.All of this cooling proceeds against the background"tof the natural regime of the ground temperature,which is variable over time and is dictated by air+d.temperature fluctuations. Thus the resultant meanannual temperature of the frozen ground for anypoinr in the foundation can be expressed as a curvewhich will reflect the lowering of the mean temperatureand subsequent attainment of a minimum constantvalue; this curve will also reflect seasonal fluctuationsdictated by variations in the natural airFIGURE 2 Processes, varying with time, which should temperature (Figure 2). Both the strength characbetaken into account in calculating the bearing teristics and mechanical properties of the subcapacityand strain on frozen sediments forming the foundation materials will also vary accordinglyfoundation of a structure:with time.a) changes in temperature of frozen sediments $Under the influence of an external load the prowithtime;cesses of creep deformation and reduction of theb) variations in load P with time;strength of the materials will develop simultanec)reduction, with time, of the long-term strength ously with time. At the same time the externalof sediments R where R = constant and TI is also load itself may change with time, both during theconstant;construction period and while the structure is ind) development over time of creep srrain S where 0 operation (Figure 2). The challenge is to designis constant and P is also constant.a method of calculating the bearing strength and

181the settlement of the foundation which will takeall these processes into account. The method describedwas worked out by the author and presentedin his work Temosvai V strotez'stvc nu Severe[Thermal piles in construction in the North] (1983)on the basis of equations of long-term strength andof creep deformation of frozen sdeiments with temperaturevariations and load variations over time,which he had derived earlier. These equations werepresented at the Third International PermafrostConference (Vyalov 1978a, 1978b).Figure 3 presents the results of determinationsof the bearing capacity of piles in permafrost undervarious temperature regimes. If one regards themaximum mean monthly temperature of the sediments394 kN8 = 0,3"C as being a calculated one, the value for 3.the bearing capacity P will be least and we willassume it to be unity (Diagram 1). If one takesinto consideration the sinusoidal change in themean monthly temperature along with a simultaneouslowering of the temperature due to the provision ofa ventilated crawl-space and installation of thermalpiles, then the value o€ P will increase by 1.51times (Diagram 2). One should note that if in orderto simplify the calculation one substitutes maximumvalues, changing in step-wise fashion (Diagram 3)or linearly (Diagram 4) for the sinusoidal oscillationsin temperature, the value of P will increase1.18 or 1.48 times. If at the same time the loadis taken to be increasing throughout the constructionperiod rather than constant, the value of Pt0 t,will increase 1.78 times (Diagram 5). And finally,0, ,Iif the sediments are pre-cooled from -0.3" to -1.2"Cand one also takes into consideration subsequentcooling then the value of P increases by a factorof 4.2.Thus the proposed method.of taking into considerationthe temperature variations in the sediments FIGURE 3 Bearing capacity of pile P with variousallows one ro determine the bearing capacity of the temperature regimes in permafrost.foundations under a wide range of temperatureregimes in the subfoundation materials and toincrease substantially (by a factor of from 1.5 to4) the designed bearing capacity of the foundation.One should note the great significance of taking maximum, but rather is close to its minimum value.into account the variability of the load on theAn analogous situation may be observed when onefoundations. Even if one considers only the in- considers snow and wind-induced loads. Thus Figurecrease in load during the construction period (as 4 presents graphs (in relative units) of the changeoccurs in reality) then the designed value of the over time in the wind load (N) acting on an elecbearingcapacity increases by a factor of 1.64 (see tricity transmission pylon in the Vorkuta areadiagrams 4 and 5).(curve 2) and changes over time in the bearingBut an even greater effect is achieved when one capacity $ of its foundations, which involvetakes into account the short-term impact of climatic thermal piles (curve 1). The maximum value of Nloads, namely snow, wind, or the forces of frost is reached in March, whereas the minimum value ofheave. This is particularly imporrant for light the bearing capacity ($) is reached in July-August.structures, e.g. pipelines, electricity transmis- The curve of variation in the ratio N:$ Over time,sion lines, and also for buildings constructed of which dictates the necessary designed area of thelight materials, in that €or such installations thermal piles supporting the transmission pylon (F)these loads are critical. At the present time the (curve 3) reveals thar the lowest value for thisshort-term impacts of loads are not taken into ratio occurs in August. This ratio is half what itconsideration and the strength characteristics of would have been had one taken a maximum value forthe sediments built into the design are calculated N and a minimum value for b.on the basis of the maximum mean monthly temperaturein summer. In fact the maximum climaticFoundationsloading as a rule does not coincide in/time withthe maximum ground temperature, which in factcoincides with the minimum bearing capacity of thematerials. Thus, for instance, the maximum forcesassociated with frost heave develop winter, whenthe ground temperature is certainly not at its2.t. Time (hr)1max OH= - 0.YC P = 346kNTemperature OOC0-t-I509 kNWithout dwelling in detail on the type of Eoundationsused where the method of preserving thepermafrost has been adopted in construction, inthat this question will be discussed a panel atsession at this conference, I wish to focus only

FIGURE 4 Changes over time in wind loading N on anelectricity transmission pylon (2) and in the bearingcapacity @ of a thermal pile (1) and thedesigned value for the area of a thermal pile F (3).182increasing its frost-resistance. These topics arediscussed by Poluektov (1983) eConstruction where the Permafrost hasBeen Allowed to ThawWhere one uses the method whereby the frozensediments beneath a foundation have been encouragedto thaw, this introduces the need to solve theproblems: 1) of determining the shape of the thawzone beneath the structure and its evolution overtime; 2) of determining the strain and strengthcharacteristics of the thawed sediments; 3) ofdeveloping methods of reducing the magnirude andvariability of settlement in the thawed foundationmaterials; and 4) of developing methods of calculatingthe combination of forces involved in theinteraction between the structure , its foundationand the supporting thawed sediments.The methods for making the thermal-technicalcalculations involved in thawing foundations arepresented in the Building Standards and Rules andin the Manual to them, as well as in the books byG. V. Porkhayev and V. V. Dikuchayev. Values forthe thermophysical properties (e.g. thermal conductivity,heat capacity) for various types ofsediments in both frozen and thawed conditions andsupplementary monograms for calculating such valuesare also presented in these works. To obtain moreaccurate results a computer was used and programsfor such calculations have been developed.A coefficient of thawing, A, which determinessettlement due to thaw and is independent ofon the following aspects. The major type of foun- load So, and a coefficient of compaction a = Sp/p,dation used in construction according to the first describing the settlement due to compaction beneathprinciple involves the use of piles. Perfection the load and the weight of the sediment itself, areof the technique has been achieved by the composi- used as the calculated deformation characteristicstion of the slurry grouted into the bore hole; the of the thawing sediments, i.e. S = So + Sp = h(ASslurry composition now selected (a sand-limeap) where h is the thaw depth a at given point.mixture) is designed to achieve optimal adfreezing Laboratory determinations of the coefficients A andstrength and to ensure conditions of equal shear a were made by means of testing sediment samples asstrength between the slurry and rhe surface of the they thawed under pressure, but without any possipileand at the contact with the surrounding frozensediments. In order to increase the bearing capacbilityof lateral expansion. But these experimentswere of a supplementary nature. The major experiityof the pile we have begun using (e.g. at Norill- ments were field tests using a heated press.sk) gravel pads are placed beneath the butt end ofThe methodologies of both laboratory and fieldthe pile and tamped down as the pile is installed. tests complied with the appropriate standards.In the case of soft materials (saline or plastically Strength characteristics (adhesion, angle of interfrozen)concrete expansions of the foot of the pile nal friction) were determined for the usual shearare being used (e.g. at Yakutsk). Methods of test- tests although the physical characteristics (density,ing pile performance in permafrost have been con- moisture content) which the sediments assumed aftersiderably improved by means of test loadings; thawing were also taken into account.standards for such tests have been developed.Reduction in the amount of settlement isMethods of calculating and installing founda- achieved by controlling the thawing process. Thetions in saline, peaty or ice-rich sediments and most effective method involves prior thawing. As aeven in ground ice have been developed in fair result of this thawing the bulk of the settlement,detail. These tooics are discussed in the follow- i.e. settlement due to thaw (S = Ah) and part ofing works: Vyalov et al. (1976, 1980), LenZNIEPP the settlement due to compaction under the sedi-(1977), Gaydayenko (19781, and Roman (1981).ments' own weight (Sg = ayh'), occurs prior to erec-One should note that where ferro-concrete pile tion of the building. Subsequent settlement,foundations have been used, cases of frost-damage occurring during operation, is reduced a to minimum.to the concrete of the pile within the active layer The prior thawing may involve only part of the totahave been found. This can be explained by the depth of the potential depth of thaw, the amountextreme temperature and moisture conditions affect- being determined by calculation (Figure 5). Theing the upper part of the emplaced pile during thawing is usually achieved using by either hotseasonal freeze-thaw in the active layer, Measures water or electrical heating. A number of buildingshave been developed to prevent this phenomenon; has been erected using this method in Vorkuta,they mainly involve prevention of the penetration Magadan oblast, and elsewhere, but sometimes solarof soil moisture into the concrete of the pile, and heat alone is sufficient.

I ...............................................a.183tolerate any remaining settlement and any seismicactivity. All of this was calculated using a computerprogram which modelled the system encompassingthe building, its foundation and the sedimentsbeneath.In the example cited the volume of sediments tobe thawed was minor, and hence it could be achievedby natural processes, In the majority of casesprior thawing requires a great deal of expensiveand protracted work. Hence a method of local priorthawing has been developed whereby the thawing islimited only to where the foundations are to beemplaced. In this case sill or pile foundationsare used (see Figure 5).bThe design of the foundations in one of the newtowns of Western Siberia may serve an as example,3The sediments beneath the building site consist ofice-rich silty sands. Just as in the previousexample the permafrost here is unstable, with atemperature close to 0". Construction using thetechnique of preserving the permafrost was technicallyand economically inexpedient. But it wouldbe impermissible to let the sediments thaw outduring the operation of the structures, since thiswould lead to major settlement, The solution wasprior thawing, but in view of the great thicknessof the permafrost, thawing the sediments beneaththe site of every building in town would be extremelylabor-intensive. Hence the technique of localthawing was adopted, the foundations used beingFIGURE 5 Prior thawing of sub-foundation perma- single piles or groupings of piles. When the pilesfrost sediments:were being emplaced the thawed sediments beneatha) thawing beneath the entire building using a them were compacted, thus increasing the bearingstrip foundation;capacity of the sub-foundation sediments, Thusb) local thawing on sites where piles are to be piles are being widely used in construction notemplaced.only where the permafrost is preserved, but also1. previously thawed sediments.where it is allowed to thaw.2. designed zone of thaw throughout operational A description of this and other methods of conlifeof the building.struction on thawed sediments is presented in3. permafrost.Mel'nikov and Vyalov (1961).4. local zones of thawing.Combined Operation of the System Encompassinga Building, its Poundatio_n and the UnderlyingAn interesting example is provided by the design Thawed Sedimentsof the foundations of buildings in Severobaykal'skwhere the permafrost conditions in the construction The erection of buildings on permafrost sedimentssite were unfavorable, The permafrost here is which have been allowed to thaw, when even thisunstable, with a temperature close to O"C, Although thawing has occurred prior to construction, isthe sediment consists of gravel, it is distinguished always associated with the possible incidence ofby a high content o€ ice inclusions and on thawing increased settlement. Eence along with measuresit subsides drastically. But once thawed and com- to reduce settlement it is also essential to takepacted the gravel can serve asgood foundation. measures to ensure that the design of buildings canThese sediments are 10-14 m thick, underlain by absorb such settlement. One method sometimes usedgood, ice-free gravel. In such a situation it was for buildings of frame construction involves adifficult to maintain the frozen condition of the design which provides great flexibility, e.g. byfoundation materials since this would require means of an arrangement of hinged joints, pliablespecialized, expensive methods, and it was impos- connections, etc. In such cases uneven settlementsible to allow thawing during the course of opeta- will not provoke excessive strains.tion of the buildings in that this would lead to Another, more common method, involves theexcessive settlement. Moreover the situation was opposite approach, namely increased structuralcomplicated by the high seismicity of the area. rigidity so that the structure can absorb the ex-It was decided to excavate a deep pit, leave it cess stresses from uneven settlement. This isopen for a summer, thereby encouraging the thawing achieved by reinforcement of all structural comofpart of the underlying sediments by solar heat, ponents of the building, the introduction ofon the assumption that subsequent settlement of the additional reinforcing members, and the breaking upentire sedimentary stratum would not exceed accept- of the structurb's stress components into individual,able values, The foundation used took the form of rigid blocks. The foundations are also usuallya rigid, boxlike system which would only notbuilt with extra rigidity, in the form of transversesupport the above-ground structure but would also girders, a boxlike construction system, rigid slabs,

184etc. But where one uses prior thawing it is alsopossible to use foundations, including pile foundations,which stand separately from each other.Foundations involving girders, slabs, etc. mustbe built in conjunction with the design of theabove-ground structure. Calculation of the detailsof the total system embracing the building, itsfoundations and the sediments beneath, involvesboth determining the degree of settlement and itsprogress through time, and determining the forcesinvoked by that settlement in the foundation itselfand in the above-ground structure, whereby thefoundations are seen as a component part of thestructural system of the building. The method ofcomputer calculation of rhese aspects has beendeveloped for civil buildings by the Leningradinstitute LenZNIIAP and has been presented inarticles by L. E. Neymark, V. V. Dokuchayev, etc.When one examines the interaction betweenthawed sub-foundation sediments and the foundationof a building the following initial assumptions aremade. Taking into consideration the curvilinearoutline of the zone of thaw beneath the buildingthe settlement in the sediments beneath the stripfoundation will be variable along its length. Inkeeping with this the reactive forces transferredby the sediments to rhe underside of the foundationwill also vary. In the marginal parts of the foundationstrip, where the depths of thaw and theamount of sediment settlement are least. a concentrationof pressure will occur and the reactiveforces will reach maximum values P = P$. In thecentral part of the foundation strip where thawingb. spand settlement are at a maximum the reactive forcesare minimal and may even equal zero if the thawsettlement in the sediments (So) is greater thanthe flexure of the foundation strip and the sediments"pull away" from it (Figure 6). The curvedoutline of ?he surface is determined by the changein the amount of settlement (So) along the lengthof the foundation beams (where prior thawing hasbeen effected this value is close to zero). Theamount of reactive pressure can be determined bysolving the equation for the flexure of beams onan elastic foundation. In this connection thedesign model used for thawed sediments is theelastic-plastic model, the elastic strains which inare described by Winckler's theory ol local strains.The bed coefficient in this model is determined asthe ratio of load to the amount of compactionsettlement (C = P/sp) at any given point.ConclusionsIn concluding this review article I should liketo mention that the development of engineeringpermafrost studies has allowed us to erect a widevariety of structures on permafrost materials,including multi-storey buildings and large industrialinstallations, under any permafrost conditions.But of course this demands a thoroughpreliminary engineering-geology reconnaissance andcareful design decisions which observe all therequirements of building standards and regulationsand which are based on technological and economiccomparisons of possible variants; and naturallyconstruction must be carried out so that all therequirements of this type of industrial work aremet, One should also note that despite theachievements I have listed there are still a numberof questions which require further investigation.We hope that the solutions of these problems willbe achieved through the joint efforts of academicgeocryologists and construction engineers in allthe countries where permafrost occurs. The organizationof international conferencespermafrostsuch as this will undoubtedly facilitate such jointefforts.REFERENCESBuchko, N. A. et al., 1978, Isskustvennoye zamorazhivaniyegruntov [Artificial freezing of sediments].Gaydayenko, Ye. I., 1978, Ispol'zovaniye l'dov vkachestve osnovaniy sooruzheniy [Use of as icea structural foundation].LenZNIIEP, 1977, Fundamenty na sil'nol'distykh izasolennykh vechnomerzlykh gruntakh [Foundationsin ice-rich and saline permafrost materials],Mel'nikov, P. I., and Vyalov, S. S.,PQ s=s,+s,e, 1981,Ottaivayushchiye grunty kak osnovaniya sooruzheniy[Thawing sediments as foundations forFIGURE ti Diagram of foundation design.structures].a) elastic-plastic model of sub-foundation sediments Poluektov, V. Ye., 1983, Ustroystvo fundamenrov vshowing relationship of settlement compaction vechnomerzlykh gruntakh [Construction of foun-Sp to load;dations in permafrost materials].b) diagram of interaction between the foundation Roman, L. T., 1981, Fiziko-mekhanicheskiye svoysrvastrip and the sub-foundation sediments;merzlykh torfyanykh gruntov [Physico-mechanicalc) diagram of reactive pressures in the sediments. properties of frozen peat].

185Stotsenko, V., 1912, Chasti zdaniy [Parts ofbuildings].Vyalov, S, S., 1978a, Reologicheskiye osnovy mekhanikigruntov [The rheological basis of themechanics of sediments] : Yoscow, "Vysshayashkola," 448 p.Vyalov, S. S,, 1978b, Long-term settlement of foundationsin permafrost, &Proceedings of theThird International Conference on Permafrost,v. 1: Ottawa, National Research Council ofCanada, p. 399-903.Vyalov, S. S., 1979, The interaction between permafrostand buildings, fi Proceedings of the ThirdInternational Conference on Permafrost, v. 2:Ottawa, National Research Council of Canada,p. 117-129.Vyalov, S. S., ea., 1983, Termosvai v stroitel'stvena Severe [Thermal piles in construction in theNorth].Vyalov, S. S. KaL., 1976, Podsemnye l'dy i sil'nol'distye grunty kak osnovaniya sooruzheniy[Ground ice and ice-rich materials as foundations€or structures].Vyalov, S . S. etal., 1980, Stroitel'stvo promyslovykhsooruzheniy na merzlorn torfe [Constructionof industrial installations on frozen pear].

THE CONSTRUCTION OF DEEP PILE FOUNDATIONS INPERMAFROST I N THE USSR - A SUMMARYA.V.SadovskiyResearch Instituteof Foundations and Underground StructuresMoscow, USSRThe results of scientific research and experiencerelated to the construction of pile foundationsin the U.S.S.R. have been put forth in theU.S. S.R. Building Codes and Regulations under theheadings "Building Fads and Foundations in Permafrost"(1977) and "Design Guidelines for ConstructionPads and Foundations in Permafrost Soils"(1980).There are a number of different types ofpiles and techniques for driving them. Some ofthese different types of piles are: reinforcedconcrete, metal, mod, combined, casing, and columnpiles.The basic principles for pile selection arebased on calculations of load-bearing capacity andpile deformation (i.e. settling in compliant frozenand icy soils).Calculations of frozen piles with respect toload-bearing capacity are based on long-term shearresistance along the lateral surface of the piles(1.e. adfreeze resistance) and long-term resisfanceto pressure under the lower end of the pile.The recommended design values €or these strengthcharacteristics are given in the constructioncodes, Deformation calculations are derived fromconsideration of nonlinear settling creep. Theproblem is solved using computer-generated finiteelements and is subsequently reduced Eo the simplestformulas with auxiliary nomograms. In addition,it is also solved for a general formula thatincludes equations for settling creep and longtermintegrity. The use of a generalized formulamakes it possible to determine, simultaneously,both deformation and integrity over time.Horizontal load is calculated by looking atthe lateral fixation of the pile in permafrost undervarying conditions, such as depth of seasonalthaw and the temperature of the frozen soils.Calculations for end-bearing piles are basedon the pressure resistance of the underlying rockand the integrity of pile materials with regard tolongitudinal bend. Additional negative frictionloads are also taken into consideration.The physical nature of adfreeze strength wasstudied with emphasis on the formation of an icefilm at the point of contact of the pile with thefrozen soil. The frozen soil's shear resistancewas taken as the sum of the adfreeze strength atpoint of contact and the friction forces occurringdue to radial soil compression, An equation €orlong-term frozen soil shear resistance was derived.A method of pile calculation in weak Soils(i.e. those having high saline or ice content) wasdeveloped for a condition during which the resistancestrength of the ground solution is equal a-long the lateral surface of the pile and along theperimeter of the borehole.Temperature-dependent values for maximumshear resistance along the surface of the piles(reinforced concrete, metal, wood) were calculatedfor various types of frozen soils.Increased load-bearing capacity of piles andcost-effectiveness are the result of:- the use of composite wood/reinforcedconcrete and wood/metal piles;- the use of pebble or gravel fill in a wellwith piles that have expanded concretebases;- selection of the optimal soil solutionthat is poured into the well;- artificial cooling of high-temperaturepermafrost soils, including the use ofthermo piles;- the use of drilling piles in which concretecomes into contact with the frozensoil;- the improvment of calculation methods,beginning with variable temperature andloads.Existing methods €or calculation of variabletemperatures and loads are baaed on considerationof the worst possible conditions (highest frozensoil temperature) and the worst combination ofloads. Actually, the soil temperature is variableover time due to fluctuations of the air temperature,underground cooling systems, and thermopiles.Pile loads are also variable over time.This is related to the pile's construction periodand to short-term forces, specifically climate(snow, wind, heave). Maximum loads, however, donot coincide with the minimum load-bearing capacity.Snow, wind loads, and heave forces, for example,attain their maximum values in the fall andwinter, while the smallest load-bearing capacityof the frozen earth coincides with the summermonths. Consideration of this factor is particularlyimportant for structures such as pipelines,ramps, transmission lines, and buildings made oflight materials.Calculation methods that allow us to accountsimultaneously €or variability of loads over time,soil temperature, long-term integrity, and settlinghave already been developed.Calculation methods for the construction ofpiles under special frozen conditions such asheave-ice .soils, underground ice, and salty frozensoils have been developed. When building on soils186

187where thawing may occur, as a rule, end load pilesare used, which look like large deep supports ordrilling piles. Suspended piles are also used inconjunction with preliminary local thawing of thefrozen soil and compression of submerged piles.During laboratory trials of pile models a relationshipbased on kinetic strength theory wasdetermined between specific adfreeze strength andmodel dimensions.Field trials of piles are conducted at largescalesites. These tests have been standardized.A new quick (approximate) test method in which theassigned pile load is attained using a dynamometerhas also been developed, The initial dynamometerstress is assigned, which then becomes weaker ascompression of the buried pile increases. Stressis determined based on stabilization of pile settling.Future research will involve the following:- Improvement of pile-driving technique8 inpermafrost and coarse-grained soils;- Improvement of pile construction;- Improved usage of piles in frozen soils;- Increased longevity of concrete piles;- Improvement of calculations, tables, andnomograms ;- Standardization of international testingprocedures;- Collection of data related to adfreezestrength and load-bearing capacity in awide range of conditions, which can thenbe compared in order to establish recommendedcharacteristics.

CRYOGENIC PROCESSES ASSOCIATED WITH DEVELOPMENTSIN THE PERMAFROST ZONEN. A. GravePermafrost Institute, Siberian BranchAcademy of Sciences, Yakutsk, USSRThe article first reviews the type of cryogenic processes (thermokarst, thermalerosion, thermal abrasion, frost heave, frost cracking and solifluction) likely tobe induced by disturbance of the surface in permafrost areas, focussing on theprobable variations in intensity under different conditions of climate, vegetationand ice content. The impact of the abandoned Salekhard-Igarka railway on the environment,and the degree of recovery achieved after 22 years are presented in a casestudy from near the southern limit of continuous permafrost, and are compared withthe results of a study of the Fish Creek drilling sites (Alaska), 28 years afterabandonment. Finally the author presents maps of surface sensitivity to disruptionby human activities (with four classes of sensitivity) for both the USSR and NorthAmerica. Using these he compares the areas with varying sensitivities in the twocases, and concludes that while some 7% of the total permafrost area in the USSR isextremely sensitive to disruption, rhe equivalent percentage in North America isless than 2%.Human activities in the permafrost regionsinevitably lead to the disturbance of the vegetation,soil and snow cover and even of the underlyingsediments and bedrock. Cryogenic geomorphologicalprocesses such a5 thermokarst, thermalerosion, thermal abrasion, solifluction, frostheave and frost-cracking of the ground are therebyactivated, dampened, or reactivated ar sites wherethey had not occurred previously.The primary prerequisite €or the development ofcryogenic geomorphological processes is the presenceof H,O which may be converted from the solidto the liquid phase or vice-versa under the influenceof changing external conditions. The physicsof the processes of ice formation, water migration,and of the phase changes in frozen, freezing andthawing materials has still not been adequatelystudied, although some theories as to rhese processesdo exist (Kudryavtsev 1978). At the sametime generally accepted explanations of the cryogenicprocesses which produce specific landformshave been established.Cryogenic geomorphological processes usuallyoperate together rather than separately, althoughone main process will be dominant in shaping therelief. The lead role will be assumed by differentprocesses under different environmental conditions.The major factors determining the leading processare the ice content and grain-size of the materialand the local topography. The water content of thesoil and the depth to the permafrost table play amajor role in frost heave. Climatic conditionsexert a major impact on the intensity of trhe geomorphologicalprocesses.These processes operate according to the samelaws whether under natural conditions or in areasdisturbed by human activities, although the ratesat which they operate may vary substantially.Removal of vegetation and soil cover in areas withice-rich sediments will provoke active developmentof thermokarst, thermal erosion, thermal abrasionand cryogenic slope processes, and this active stagemay last from 2-3 to 10 years. Thereafter theprocesses will gradually die away and as materialaccumulates from the slopes and becomes vegetatedthe surface will stabilize. If no further disturbanceof the surface occurs, over the subsequent10-20 years the cryogenic processes will cease orwill continue to operate at a rate comparable tothat in an undisturbed area. Frost heave or frostcracking will be activated where snow cover isremoved (Sukhodrovskiy 1979; Grechishchev et al.1983).Processes resulting in the disturbance of thesurface and of the topography, namely thermokarst,thermal erosion, thermal abrasion and, in certaincases, solifluction (in the widest sense of theterm) are the most hazardous in terms of humanactivities in permafrost areas. Thermokarstdevelops in areas with low relief. The immediatecause is an increase in the depth of the activelayer as a consequence of the removal of the vegetationand soil cover, or of the waterlogging ofthe surface as a result of the ponding of waterwhere surface flow has been intercepted.The probability of thermokarst increases withincreasing ice conrent in the soil. But the appearanceof thermokasst also depends on the nature ofthe vegetation which was removed since this willdictate differences in the depth of the activelayer a5 between the natural and the disturbedconditions. Thus, for example, this difference isgreater in areas with a moss tundra than in thosewith non-sorted circles; or in areas with a larchtayga with a moss ground cover as compared tomeadow areas. As a result the probability ofthermokarst will be greater where larch forest ora moss tundra cover is removed than in areas withcovers which are Less effective insulators,although the ice content of the soil is the same in188

189both cases (Grechishchev et al. 1983; Turbina 1982).The probability of thermokarst and the intensitythe surface, and the seepage of water from waterlines.Where these flows were eliminated or reduced,of its development will vary under different environmentalconditions even in areas with extremely the gullies partially filled with deposits whichice-rich sediments. The outer coast and interior had crept down from the side slopes and theirlowlands of Northern Siberia and Alaska may serve growth was checked; but when the flows were renewedas examples, A considerable proportion of their or intensified they began growing again. Nonethesurfacesis underlain with old clay-silt hamsless 10-20 years after the active phase of developwhichinclude very large Pleistocene and Holocene ment, the gullies stabilize and become vegetated.ice wedges and massive ground ice bodies. Extreme- Typically these forms reach dimensions 1 of km inly intense thermokarst develops with the removal of length, several tens of meters width, in and up tothe vegetation and soil cover in the tundra and 20-30 m deep. They commonly have a dendriticforest-tundra where the summers are relatively warm partern in plan view.and the surface is sufficiently moist. In polarThermal abrasion due to human activities mostdeserts, which embrace the arctic islands of both often reveals itself in the destruction of theAmerica and Eurasia and the extreme northern areas shores of reservoirs developed in ice-rich sediofthe Siberian mainland and are characterized by ments a in permafrost. Cases are known where intensebrief, cool summer and a discontinuous lichen cover, destruction of sections of the sea coast has occurremovalof the latter usually does not provoke deep red due to human activities; here thermal abrasionthawing of the ground ice masses. But in Central was generally accompanied by thermal erosion,Yakutiya when, in connection with agricultural thermokarst and solifluction. Thermal abrasionactivities, the taiga vegetation is removed from induced by human activities has been investigatedthe surface of ancient terraces which are also along the shores of the Vilyuy Reservoir, producedunderlain with clay-silt loam with massive ice by the damming of the Vilyuy River (Sukhodrovskiyinclusions, thermokarst develops only weakly anddies away at a very early stage. This is associatedwith the aridiry of the relatively long, hot into blocks and underlain by plastic rocks. Heresummers, during which evaporation exceeds precipi- thermal abrasion assumes a peculiar character. The1979). The shores of the reservoir are developedin trap rocks, broken by verrical tectonic fissurestation (Grave 1983). Evidently an identical pat- plastic rocks beneath the blocks of trap rock begantern may be observed in Central Alaska.to absorb water once the level of the water hadIn areas where ground ice masses have developed, risen and began to be compressed when loaded. Theeither as wedges or sheets, the development ofwater entering the cracks between the blocks wouldthermokarst usually reflects the shape of these freeze in winter, wedging the sides of the fissuresmasses, especially the most widespread form, namely apart even more. In sumer, as a result of thermalice wedges associated with tundra polygons. In the abrasion, the ice in the cracks melts, the blocksinitial stages this leads to a lowering of the sur- slide into the water, are broken up, and areface and the production of a hummocky microrelief, carried away into the reservoir in the of formi.e. baydzharakhy (cemetery mounds) separated bywater-filled trenches. The greatest amount ofthawing, resulting in small ponds, is observed atthe intersection of ice wedges. More acute stagesgravel. Deep clefts in the shoreline result.Where the vegetation and soil are disturbed byhuman activities on the sea coast or on the shoresof lakes or rivers in the Arctic, and where thoseof thermokarst development are represented by thaw shores are developed on ice-rich materials, thelakes. On the tundra such lakes commonly migrate;young ice wedges develop in the exposed areas ofresultant rhermokarst significantly exacerbatesthermal abrasion processes. Shores such as thesetheir beds and then, without any human inrerference, break up into blocks which collapse into the watersoon begin to melt. As a result a micro-relief offrost-heave polygons will emerge (Tomirdiaro 1980).and the shoreline retreats relatively rapidly,threatening any structures built on it. Concurrent-Thermokarst assumes different forms in areas ly with this retreat ground ice masses forming thewhere segregation ice has formed thin ice streaks coastal cliffs gradually become covered with slumpin the frozen sediments. Here the depressions deposits which ultimately put a halt to the actionwhich develop after the removal of the vegetation of the waves by forming thermally eroded terracesand snow cover take the form of small, flat-and an extensive beach. Further destruction of thebottomed pits. Thermokarst pits and ponds also coast occurs due to thermokarst and thermal erosion.€om where peat and earth hummocks are sliced off In the case of slope processes, removal of theduring the levelling of a construction site.vegetation and soil from gentle slopes developed onThe necessary conditions for the development of ice-rich sediments leads to an increasethethermal erosion are a surface gradient and the con- depth of the active layer and an increase in itscentration of drainage. In ice-rich sedimentsmoisture content. The slow processes of soliflucthermalerosion is closely related to thermokarst tion accelerate into mud flows. Observations haveand thermal abrasion. The slopes of thermal eros- shown that this process may attain velocities ofional forms are further complicated by solifluction. 1 m per minute. Flat-bottomed troughs and areasThermal-erosional gullies of man-induced origin where the surface has been lowered by thermallyhave been investigated in detail on the tundra in induced mass movement, up to 50 m in width form onthe northern parts of Krasnoyarsk kray (Sukhodrov- slopes as a result of these processes. The proskiy1979). The direct cause of the appearance and cesses do not persist actively for long. Thus ongrowth of thermal-erosional gullies in a construc- the slopes in cuttings on the Tayshet-Lena railwaytion site was the increased surface runoff due to developed in ice-rich sediments this process ceasedthe melting of snowdrifts near buildings, the dis- after 5-6 years (Sukhodrovskiy 1979).charge of industrial and domestic waste water onto Frost heave occurs during the freezing of the

190In areas without permafrost where the forest wasactive layer or during the formation of a season- removed and where snow was removed in the buildingally frozen layer in areas where no permafrostof winter or corduroy roads, the depth of seasonalexists. Human activities in areas with heave-prone freezing initially increased and frost heave wasmaterials, the associated destruction of the vege- observed; this led to the destruction of the cortationand soil covers and the compaction ox remov- duroy roads. After a few years these sectionsal of the snow cover, in general lead to differen- began to become overgrown and after 22 years atial heaving of affected areas. Pipelines, whether sparse birch forest with ground a cover of grassesburied or above ground, may experience differential and mosses had developed on the surface, while bogsheave where geocryological conditions are particu- had developed in cuttings. The seasonal freezinglarly variable; to prevent this thorough prelimin- depth had decreased to values comparable to thoseary predictive investigations are essential.under natural, undisturbed Conditions.Frost-cracking of the ground, sometimes called Elimination of the vegetation and destruction ofcryogenic cracking, is widespread in areas where the microrelief during the laying of temporary roadsdevelopments are being undertaken, as investiga- across flat, boggy areas and peat plateau areastions in Western Siberia have shown (Grechishchev where permafrost was present led to an increase inet al. 1983). Where the snow cover is removed the depth of summer rhaw, sometimes to depths ofcryogenic cracks may occur in areas where they had 4-5 m, and in these areas thermokarst pondsnot developed beneath snow a cover. The depth of appeared. Later, however, the topography becamecryogenic cracks increases with decreasing ground covered with vegetation and 22 years after thesurface temperatures and decreases as the tempera- disturbance the depth of summer thaw had decreasedture at the depth of zero annual amplitude in-again and thermokarst had almost totally ceased.creases. The depth of the cracks also increases These observations allow one to predict the resultswith a decrease in the moisture content of theof man-induced disturbances of the surface in areasfrozen ground. Thus, for example, in northernwhere industrial developments are taking place.Western Siberia the depth of cracks in sandy-loamysoils with a moisture content 20-25% of reaches9 m but where the moisture content 25-30% is itComparable investigations have been pursuedalong the routes of operating gas pipelines and ondrilling sites. Similar investigations of the conreachesonly 6.5 m. The dimensions of the poly- sequences of disrupting the vegetation and soilgonal crack-bound blocks decrease as the groundsurface temperature decreases, and vary between 10and 20 m in northern Western Siberia. Calculationshave shown (Grechishchev et al. 1983) that thehighest stresses in pipelines as a result of cryogeniccracking in areas where snow has beenremoved can be expected in clayey materials.Predictions of changes in geocryological concoverswhile drilling oil wells in the area of Fish \Creek in Northern Alaska have been carried out byAmerican specialists, 28 years after disturbancesoccurred (Lawson et al. 1975). The wells were locatedon the tundra in the continuous permafrost in zone anarea with widely developed ice wedge polygons. Thedisturbance to the surface here was due to the samecauses as in the case of the route of the railroadditions and of the development of geomorphological mentioned earlier, with the addition of spillage theprocesses as a result of man-induced disturbances of diesel fuel. The surface disruption provokedof the vegetation, soil cover and sediments may be thermokarst and thermal erosion, which are still perarrivedat either by calculation (Fel'dman 1977) orby the recently developed method of geocryologicalsisting at the present time.These examples cited from the continuous permaengineeringanalogy (Grechishchev et al. 1983).frost zone with ice-rich sediments (Alaska) andThis latter method is of particular interest since from a zone of sporadic permafrost near its southernit is based on investigations of developed areascontinued over many years. By selecting landscapeslimit (Salekhard-Igarka) demonstrate that the"healing" of man-induced thermokarst and restorationundisturbed by human activities, but otherwise of the vegetation occurs considerably more slowly inidentical to the developed. areas, one an has oppor- the Far North than in the more southerly parts oftunity to follow and predict the probable changes the permafrost zone.which will result from various kinds of development.As an example the work cited above presentsthe results of investigations along a section ofthe route of the now abandoned Salekhard-Igarkarailroad. This section is located in the sporadicpermafrost zone, the permafrost islands coincidingwith hummocky peatlands and bogs. Large-scale airphotos of this section of the line, flown prior tothe start of construction (19491, and 15 years laterafter work on the line had been abandoned (1966)On the basis of both experimental data and calculations,predictive maps showing the distributionof the parameters of frost cracks which will resultfrom removal of the snow covet have been compiledfor the northern part of Western Siberia (Grechishchevet al. 1983). The distribution zones delineatedillustrated both the depths of the cracks andthe dimensions of the polygons, both of theseparameters being related to the distribution ofaverage January air temperatures in the area. Thuswere studied, and data from engineering site in- the dimensions of the polygons increase from 10 tovestigations were analyzed. Control studies weremade in the summers 1973 of and 1974.20 m from northeast to southwest, while the depthof the cracks increases in the opposite directionDuring construction of the railroad the forest from 3 to 9 m.was cut down, both winter roads and permanentcorduroy roads were built, the vegetation was coverCryogenic geomorphic processes initiated byhuman activities within the permafrost region areremoved, and the soils were stripped off to depths conditioned by the sensitivity of the surface toof 0.2 to 0.3 m. Trenches and ditches were dug,temporary buildings and installations were erected,drainage was blocked and lakes lowered, whiletechnogenic operations. Analysis of the data inthe literature on ice contents, thermal settling,grain sizes of the frozen materials and physicalindividual areas were either drained or became boggy. geographical conditions in the permafrost zone

19 1LLegend :1-4: Regions with different degrees of 5: Regions with pennafrosr islands andsurface stability predominating:1A - very unstablesporadic permafrost6: Southern boundary of the permafrost1B - very unstableregion2 - unstable 7: Southern boundary of the region of3 - slightly stable continuous permafrost and massive4 - relatively stable permafrost islands.FIGURE 1 Map of the permafrost zone in the USSR illustrating sensitivity of the surface to removalof the vegetation and soil covers during developmentwithin the USSR has permitted me to delimit fourclasses of surface sensitivity to removal of thevegetation and soil covers during industrial developments,and to illustrate their distribution interms of a schematic map (Grave 1983). A comparablemap has also been developed for North America. Thetwo maps are presented a5 Figures 1 and 2.To a certain degree these maps also illustratethe dominant cryogenic geomorphological processesoperating on the surface, which would be activatedor reactivated by man-induced disturbances.In regions 1A and 1B with highly sensitive surfaces,the dominant process would be thermokarst,with the addition of thermal erosion and thermalabrasion in the north. In region 1A this wouldinvolve deep thermokarst associated with the meltingof massive ice wedges, whereas in region 1B thethermokarsr would be limited only to the earlystages of development.In zone 2, also with an unstable surface, thedominant process would again be thermokarst, butoperating on less massive ice wedges and on segregationice to produce primarily shallow, flatdepressions in the surface. The role of solifluctionand creep would be more significantIn region 3, with only a mildly unstable surface,solifluction and mass movement phenomena, includingrock glaciers, assume a more important role. Inregion 4, with relatively stable surfaces, a majorrole is played by slope processes, includingcatastrophic processes such as rock slides, mudflows,etc.The geographical distribution of the predominantsurface types, in terms of their sensitivity to theremoval of vegetation and soil covers, is shown in ageneralized, schematic fashion on the regionalizedmaps of the permafrost zones of the USSR and NorthAmerica presented a6 Figures 1 and 2.It is interesting to calculate the areas occupiedby the surfaces with various degrees of susceptibilityto thermokarst; this has been done by S. P.Gribanova using a planimeter for the zones of continuousand massive-insular permafrost in the USSRand North America (Table 1).The accuracy of the figures presented is relative,and corresponds to the accuracy of the chosenzone boundaries delimited on the maps. At the sametime the interrelationships of the areas of thedelimited zones are fairly obvious.

192Legend1-4: Regions with different degrees ofsurface stability predominating:1A - very unstable1B - very unstable2 - unstable3 - slightly stable4 - relatively stable5: Regions with permafrost islands andsporadic permafrost6: Southern boundary of the permafrostregion7: Southern boundary of the region ofcontinuous permafrost and massivepermafrost islands.FIGURE 2 Map of the permafrost zone of North America illustrating sensitivity of the surface to theremoval of the vegetation and oil covers during developmentTABLE 1 Approximate areas of varying degrees ofsurface susceptibility to man-induced thermokarst(thousands of km2)Degree of surfacesusceptibilityAreaUSSR North America1A Extremely susceptible 559 40lB Extremely susceptible 161 552 Susceptible 2,800 7503 Slightly susceptible 1,600 2,6004 Relatively stable I, 900 1,410Total area of continuousand massive-insularpermafrost 7,020 4, a64

193In the USSR widespread extremely sensitive sur- my of Sciences, p. 367-373.faces occupy an area in the order of 720,000 km2, Grechishchev, S. Ye., N. G. Moskalenko, Yu. P. Shur,representing about 7% of the entire permafrost zone et al. 1983, Ceokriologicheskiy prognoz dlua(including the discontinuous and sporadic zones), Zapadno-Si-birskoy gazonosnoy provintsii [Geocryoorabout 10% of the continuous and massive-insular logical prediction for the West Siberian gaspermafrostzones. In North America extremely sen- bearing province]: Novosibirsk, Nauka, 180 pp.sitive surfaces occupy approximately one seventh of Kudryavtsev, V. A., ea., 1978, obshchee merzZotovethisamount (about 100,000 knP), representing less deniye (geokrioZogiyal [General permafrostthan 2% of the area with continuous and massive- studies (geocryology], second edition, revisedinsular permafrost. It is obvious that only some and enlarged: Moscow, Izdatel'stvo MGU, 464 pp.parrs of the total. area of the permafrost zone is Lawson, D. E., J. Brown, K. N. Everett, A. W.susceptible, if developed, to catastrophic settle- Johnson, V. Komarkova, B. N. Murray, D. F.ment and disruption of the surface and to irrever- Murray and P. S. Webber, 1978, Tundra distrubancesible changes in the landscape a in direction whichis undesirable from the human viewpoint.and recovery following the 1949 exploratorydrilling, Fish Creek, Northern Alaska: CRRELFurther investigations should be directed to pin- Repork 78-28, Hanover, NH, 91 pp.pointing the consequences of human activities in the Sukhodrovskiy, V. P., 1979, Eksogennoye re2 'yefobrapermafrostzone and to perfecting the mapping ofareas which are particularly hazardous in thiszovaniye v kriolitozone [Exogenic relief formationin the cryolithozone]: Moscow, Nauka,respect, both with regard to the environment and to 277 PP*society.Tomkrdiaro , S. V., 1980, Lessovo-Zedovaya fomatsiyaVoostoahnay Sibiri -11 paadnm pZ@lstotsene iLITERATUREgolotsene [The icy-loess formation in EasternSiberia in the late-Pleistocene and Holocene]:Fel'dman, G. M., 1977, Prognoz tcmperaturnogoMOSCOW, Nauka, 184 pp.rezhima gruntov .i razv.it.iya kriogennykh protses- Turbina, M. I., 1982, Evaluation of geocryologicalsou [Prediction of soil temperature regimes and conditions in the valley of the middle Amga, inof the development of cryogenic processes]:Connection with the agricultural development ofNovosibirsk, Nauka, 191 pp.the area (based on the example of the Betyun'Grave, N., 1983, A geocryological aspect of thearea, in: Termiku pochv .i gornykh porod V kholodproblemof environmental protection, &: Pro-ngkh rzonakh, [Thermal aspects of soils and bedceedingsof the Fourth International Conferencerock in cold regions]: Yakutsk, Permafroston Permafrust: Washington, D.C., National Acad- Institute, SO AN SSSR, p, 135-141.

Contributed Soviet PapersTHE PHYSICOCHEMICAL NATURF. OF THE FORMATION OF UNFKZENWATER IN FROZEN SOILSYu. P. Akimov, E. D. Yershov, and V. G. CheveryovGeology Department, Moscow State UniversityMoscow, USSRThe paper examines how the liquid phase of H,O is influenced by the basic physicochemicalfactors in permafrost: average size of particles and pore-spaces, polydispersityand heteroporosity, specific surface, surface energy, structural bonds,composition of the solutions in pore-spaces, temperature, etc. The trend of thecurve showing the relationship between the unfrozen water content and temperatureis described theoretically; physics-based constants are an integral part of theformula used in calculating this relationship. The surface energy of the mineralskeleton of the soil is found to be dominantdictating the presence of H,O inthe liquid phase; the contribution made by the quasi-liquid on the film ice surfacewas proved to be non-critical. As one proceeds from macro to microporous soils andfrom coarse to fine ones, the percentage of capillary water increases and that offilm water decreases. It was shown that the relaxation time of unfrozen water doesnot exceed one hour. The correlation between typical soil moisture contents and theamount of unfrozen water was explained on a physicochemical basis; the thermodynamiccharacteristics of the unfrozen water are also discussed. fie relationships betweenthe physicochemical and petrographic parameters of frozen soils were demonstratedand on this basis the rules governing the formation of liquid B,O in soils ofdiffering genesis, age and granulometric, chemical and mineralogical compositionsare demonstrated and explained.The present-day physics, chemistry, and rnechanicsof frozen soils are impossible withoutstudying the interaction between soil skeletonparticles and water. Many aspects of this interactionare the same as or similar to the interactionof water with mineral particles at positivetemperatures.It was a great achievement for soil physicalchemistry when changes in the properties and structureof bound water were proved to be influenced bymineral particles. The reverse influence of wateron structural parameters of the particle surface,for example, on parameter "b" of their crystallattice (Osipov 1979) also has an important effect.Minerals, having great surface energy, make waterdifferentiation between the surface structure andthat of associates and more surface energy at thedisposal of the mineral particles (Saveljev 1971).This is well-illustrated by the quantitative increaseof loosely and tightly bound water thatoccurs as the temperature drops (Yershov al. et1974) *Lowering the temperature below O°C leads to anew water phase-ice. It is acknowledged now thatice in frozen soil is not an inert body. Havingconsiderable surface energy and water-absorbingcapacity, ice itself causes the formation, close toits surface, of a thin layer of intermediate-phasewater at both the ice-air and ice-liquid waterinterfaces. Likewise, the structuring activity ofmolecules nearest to their particles reorient in unfrozen water also has an impact on ice since itssuch a way that the StrucKure of the nearest water 0-0 atomic gaps get larger (Kurzayev et 1977). al.layers most fully corresponds to the location of Thus, it turns out that unfrozen water has multipleactive surface centres of particles, i.e. to the layers; the water close to the surface of soilsurface structure of the mineral. Naturally, lower particles is bound mostly by them and water close towater temperatures result in further transmission the ice surface is bound mostly ice, by while itsof this type of structuring to water at greater interstitial portion is under the orienting effectdistances from the surface (since an increase in of both surfaces. This explains the nonmonotonictemperature promotes diffusion of the orientedwater structure due to thermal motion), increasedrelationship between unfrozen water density andaqueous film thickness (Anderson and Morgenstern195

1961973) and the minimal heat of the ice water phase interval may last from several to 24 hours. Thetransition at the initial freezing temperature of total moisture content in the initially dry platestightly bound water (about -7"C), where enthalpy corresponds to the equilibrium content of unfrozenvariation at ice-water transition varies fromtabular values by a factor 6 of (Anisimov andTankaev 1981).Absence of an orienting ice surface causesmonotonic change in the orientation of watermolecules as they move away from the particlesurface and a monotonic decrease of water-icetransition heat to zero when the moisture in unwaterat a given temperature (Yershov et 1979). al.The importance of structural and adsorptive characteristicsin the formation of the liquid phasecontent in frozen soils depends on a synthesizedinterdependent relationship between pore spacestructure and the specific active surface of soils.The results of experiments carried on out frozensoils having different moisture and size of icefrozen water is close to hygroscopic and the temp- crystals allows us to conclude that the quasi-liquiderature is about -7O'C.film on the ice-air interface in the total unfrozenA series of interesting publications, dedicated water content is nonessential.to the -liquid phase content in frozen soils, has It has also been proved experimentally that theappeared in the last five years. The use of methods surface energy of the mineral skeleton can besuch as the NMR-spin echo permits us to deduce that reduced by using water repellants, resulting in aunfrozen water may have at least two categories, sharp drop in the soil's liquid phase contentwhich differ sharply in their molecular mobility (Yershov et al. 1979).(Ananyan et al. 1977). The mobile liquid phaseThis indicates that the unfrozen water Content iscontent is not permanent and decreases as the temp- almost entirely dependent on the liquid phase oferature drops according to the relationship between water in small-diameter nonfreezing capillaries andthe unfrozen water content (\Iu) and temperature (t). on film water close to the surface of mineralThe amount of water in the liquid phase showing very particles.low mobility varies little with temperature and isclose to maximum hygroscopic moisture.One of the new research trends in this fieldrelates to the relaxation time of unfrozen water(Danielyan and Yanitsky 1979, Yershov et al. 1979).The non-equilibrium of water transitions is causedby three major factors: delay in water transitions(discounting the effect of soil minerals), delay intransformation of soil texture and structure, anddelay in mineral skeleton-water interaction. ItAs macroporous soils are gradually replaced bymicroporous ones, the specific surface becomes lessimportant, while the pore space structure acquiresgreater significance. Thus, the pore space structureis the most important factor in formation ofunfrozen water and ice in microporous soils, especiallyat high temperatures.To estimate the content of water not freezing insmall-diameter capillaries we can consider the factthat the distribution of pole volumes by radii canhas been shown that after the temperature has beenwell-described by lognormal law (Yershov et al.set, it takes unfrozen water an hour to reach an 1979):equilibrium value, with the relaxation time dependingon the mineralogical composition, texture, andstructure of the soil.Using soils of different genesis, composition,texture, structure, and properties a series of comprehensivestudies has revealed the physicochemicalcontent of the liquid phase in frozen soils. Forthe first time in world practice the structure ofsoil pore spaces has been studied using mercuryporosimetry; the unfrozen water content has also Here, Vo is total pore volume; V is the volumebeen determined by the contact method and others. of pores having a radius smaller than rl; or, mrThe contact method for determining the liquidphase content is simple, reliable, applicable to aare root-mean-square deviation and mode, respectively.wide range of temperatures and accurate to apptoxi- We can then use the relationship between themately f0.3%. This method does not require special absolute drop of freezing temperature (AT) of waterequipment-the only thing needed is a refrigerating in capillaries and their radius (r):cabinet with a temperature control device to maintainisotropic distribution and to record tempera- 2wwa To w - wtures with an accuracy of *0.loC. For investiga- lgr=lg sa-a sw - lgAT,tion purposes, 3 ~4~0.5 cm cooled plates, made ofPLw wadried-up soil, are covered on the two largest faceswith plates of ice or the same soil, which has beenwater-saturated and frozen. Using polyethylene film where: Us,, wsw are specific interfacialthey are made waterproof, pressed on top and put energies (water-air, soil-air, and soil-waterinto the refrigerating cabinet at the required respectively); To is a normal freezing temperature;temperature. When the dry plates come into contact p. L are density and specific heat Water of tranwiththe ice, liquid exchange and saturation of the sitions, respectively.dry soil with water take place due to intensive On substituting lgAT for y, lg r for x andair, film, and capillary water transfer. The ther- 2WwaTo (rl - wmodynamic equilibrium of three liquid phases and thefor b, equations (1) and (2)discontinuation of water exchange occur some timelg PL sa wwa swlater; depending on mineraological composition, the may be combined to give the volume of water nottexture of the soil, and the temperature, this time frozen at AT1:

197wu.%24 -WU,%20 -16 -/312 -tu -E --t,CU 2 d 60 2IY 6-t: cFIGURE 1 Influence of heteroporosity (a) and average pore radius (b) on unfrozenwater content-temperature relationship in frozen soils: 1 - kaolin (ur = 0.18,7 = LO2 nm; s = 15 m2/g); 2 - Cambrian illite clay (ur = 0.41, ? = lo2 nm; 6 = 16: t J~ = 0.58) ; 4 - heavy sandy loam (P = 2 -These experiments have shown that when soilsare mixed, the proportional summation of pore spacestructures and specific active surfaces leads toadditivity of the unfrozen water content (Yershovet al. 1979), i.e. Wu is equal to the mean-weighedwith my = b - mr. Assuming that unfrozen Watercontent of unfrozen water produced by calculatingdensity is a tabular value, Wu can be set equal tothe sum of all its components (capillary and filmthe Wi values for the i-th soil composing thewater)mixture::soils characterized by more uniform pore space,small average radius of pares and larger specificactive surface (Figure 1). In addition, the unwheresi and s are specific ice-air and mineral-air frozen water content at low temperatures is largerinterfaces; uia, uiW are specific ice-air and icewaterinterfaclal energies; K i s the minimum sizein nonuniformly porous soils and smaller at hightemperatures, when compared to monoporous onesof a drop at which one can begin to detect liquid (Figure 1). The nature of pore volume distributionproperties,by radii probably accounts for the S-shapedThe second term of the right member determining relationship between the unfrozen water content andthe share of the quasi-liquid film on the ice surfaceis of minor importance in the formation ofunfrozen water. The first term determining the Wuporespace relationship of the structure may betemperature obtained in the experiments of variousauthors. These conclusions made it possible todetermine the physicochemical nature of unfrozenwater formation in soils of different mineralogicalreplaced by an approximate linear form: Wu vscomposition, texture and structure.1gAT. Actually, the W,-temperature relationshipsTo make a pure assessment of the influence ofin these coordinates are linear, which indicates soil dispersity on the Wu value, two cases shouldthe particular importance of pore space structurein unfrozen water. The specific surface size,therefore, does not exert direct influence on theliquid phase content. The reason is that, even atlow moisture contents, ultracapillary pores, whichdetermine the specific surface size, turn out tobe full of water. This immediately reduces (by1-3 orders) the specific surface size, i.e. thebe considered. In the first case polydispersity isthe same (estimated by the root-mean-square deviation(Ud) of the pzrticle size) while the averagesize of particles (dl differs. This allows for amore precise analysis of the effect of particlesize. Representative soils are heavy silty loam(d = 10 mcm), light silty loam (d-= 30 mcm), andcoarse-grained light sandy loam (d = 100 mcm).size of the surface that is capable of furtherwater binding,where ai is a share of the i-th soil in the mixture.The material presented above helps in under-standing the physicochemical peculiarities of Wutemperaturerelationship. The range of intensivephase transitions is observed to be broader inThe ud value is equal'to 0.65 in all soils. Thereduction of particle size can first be detected by

1986'6FIGURE: 2 Relationship between average pore radius(7) and root-mean-square deviation (Dd) of particlesize distribution at different average sizes ofparticles (dl: 1 - 3 = 1 * lo4 nm; 2 - d = 2 * 10' nm.a reduction of the average pore radius (approximately10 times), as seen in Figure 2, and secondly,by an increase in specific surface. The sharpestincrease in the unfrozen water content occurs whenthe particle size changes from 100 to 30 mcm, andin heavy loam the liquid water phase content is3-4 times greater (depending on temperature) thanin sandy loam. It should be noted that due toavailability of montmorillonite in light loam, itsspecific surface is larger than that of a heavy one.In the second case, the influence of polydispersityis determined by selecting soils similarin d value and different in polydispersity ("d).Increased polydispersity makes the pore spacestructure much thinner (Figure 2) while thespecific surface expands at a slower rate. Therefore,in heavy sandy loam, fairly uniform in grade,the unfrozen water content is 1.5 times smallerthan in light loam. The greater importance of unfrozenpellicular water and the smaller, comparedto loam, importance of the capillary component ofunfrozen water results in a more even Wu(t) relationshipin sandy loam, since the content ofunfrozen film water varies slowly at t < -hoc(Figure 1).With a decrease in average particle size and anincrease in polydispersity (these being the mainfeatures of sand-clay transition) the unfrozenwater content grows larger and the range of intensivephase transitions wider due to proportionalreduction of the average pore size (Figure 2) andthe specific active surface of soils. During sandclaytransition, the capillary water increases,while unfrozen pellicular water decreases. In thiscase, the film thickness decreases by approximatelyone order, which is caused by a decrease in thespecific surface energy (Rusanov 1967), and by amore rapid, compared to large particles, loweringof the force field stress as the mineral soilparticle moves away from the surface (Andrianov1946). Nevertheless, Wu increases as the transitionto soils having small average size particles takesplace, due to reduction in the size of the porespaces and a rapid increase in the specific activesurface of soils.It is known that the unfrozen water content at atemperature lower than -1'C is maximum in montmorilloniteclay, minimum in kaolinite clay, and mediumin illite clay, although the specific waterabsorbingcapacity of montmorillonite clays islower than that of kaolinite clays (Osipov 1979).The given soils are characterized by small specificsurface energy and plasticity of the montmorillonitecrystal lattice, which promotes high particle dispersityand an additional, in contrast to mineralswith a nonplastic lattice, mode of pore volumedistribution by radii in the area of r < 10 nm;this, in turn, increases the content of unfrozenwater in montmorillonite clays. The small particlesize and high polydispersity of montmorilloniteclays, in which the high unfrozen water contentresults from a small average radius (about 30 nm)of intra-aggregate pores, facilitate this effect.Despite its large particle size, high polydispersityof illite clay resulting from its mineralogicalcomposition, as well as the smaller averagesize of pores and very nonuniform pore space, makeits unfrozen water content much larger than inkaolinite clay, even though their specific surfacesare practically the same (Figure 1).A typical feature of the capillary mechanism ofunfrozen water formation is its behavior attemperatures close to 0°C. In this case the GJurate of change attains hundreds of percent perdegree. Yareover, in soils with different mineralogicalcomposition high initial rates of changeoccur in the water-phase content at varioustemperatures. For kaolinite clay it comprisesapproximately -0.6"C, for montmorillonite clayapproximately-0.3"C. This attests to the importanceof the second (the third for bentonite) modeof pore volume distribution by radii, which dependson the size of interaggregate pores. The averagesize of bentonite microaggregates is twice that ofkaolin despite very disperse grading. Accordingly,the size of interaggregate pores in bentonite isgreater. This explains the rapid increase in theunfrozen water content in kaolin which at a temperaturehigher than -0.5'C becomes considerablylarger than in bentonite (Figure 1).Interaction of salts with the mineral skeletonsurface and water governs the relationship betweenthe unfrozen water content and soil salinity. Soilswith a relatively small specific surface (bothsands and clayey soils) are characterized by greatdependence of the water phase content on salinitybecause particles of the diffusion layer of ionsare but slightly suppressed by the diffusion layerclose to the surface. At the same time suppressionof the diffusion layer of ions is quite noticeablein soils having well-developed specific surface.This results in three ranges of the W,-salinityrelationship (Yershov et al. 1979). The lower thecryoscopic constant of this salt solution, thebroader the range of weak salinity impact. Whenthe diffusion layer of soil particles is completelysuppressed by the diffusion layer of ions, anincrease in Wu from salinity is in line with thetheoretical relationship. The influence of poresolution concentration on the water phase contentin frozen soils can be presented as a tangent variationof the slope angle of the straight line showingthe relationship between the unfrozen watercontent and temperature and plotted according to a

19932wu, %unimodal in opokas, where the pore radius less isthan 10 nm. Thus, the volume of pores with thisradius increases from zero in .diatomites20% intripolites and to 80% or greater in opokas, whilethe total pore volume decreases in all these sailsAccordingly, the unfrozen water content decreasesat high temperatures (t > -1.5'C) and increases atlow ones. In opokas, however, the change in Wuvalues is less noticeable (Figure 3).24i68FIGURE 3fRelationship between unfrozen watercontent and temperature in siliceous soils:1-diatomite; 2 -diatom clay; 3-tripolite;4 - opoka .logarithmic dependence. This influence can beestimated using cryoscopic constant of the solution,which is dependant upon the ionogenic capacity ofsalts and the interaction of ions with each otherand with water molecules.Thus, there exist complex inter-relationshipsbetween the unfrozen water content, structural andadsorptive parameters of soils, their grading andchemical and mineralogical compositions. Theserelationships are dictated by the conditions offormation and lithogenesis of dispersed deposits.Research into these relations should us help toexplain the behavior of the unfrozen water contentin soils of different geogenetic types (Yershovet al. 1979).The explanation of the nature of unfrozen waterformation is applicable not only to loose soils butalso to tightly bound ones-sandstones, argillites,aleurolites, and siliceous soils (diatom clays,diatomites, tripolites, and opokas). Siliceoussoils clearly show how their age influences theirunfrozen water content. In the course of gradualtransition from diatomites to tripolites, resultingLrom diagenesis and catagenesis, the volume ofr = 4.102 nm pores decreases and, accordingly, thevolume of those with a radius smaller than 10 nmincreases. The next stage of lithogenesis resultsin disappearance of = 4*102 nm pores typical fordiatomites and the formation of distinct bimodaldistribution of pores by radii that changes forREFERENCESAnanyan, A. A., Golovanova, E. F., and Volkova,E. V., 1977, Issledovanija sistemy kaolin-vodametodom spinovogo eha. Transactions "Svyazannajavoda v dispersnyh sistemah," issue 4:Vmscow, Moscow University Publications, p. 172-177 aAnderson, D., and Morgenstern, N., 1973, Physics,Chemistry and Yichanics of Frozen Ground, Proceedingsof the Second International PermafrostConference: Yakutsk: Washington, D.C., NationalAcademy of Sciences.Andrianov, P. I., 1946, Svyazannaja voda pochv igruntov: Moscow-Leningrad, USSR Academy ofScience Publications.Anisimov, It. A., and Tankaev, Kt U., 1981, Plavlenijel'da vblizi ghidrofil'noi poverhnosti.Journal of Experimental and Theoretical Physics,v. el, issue l(7) , p. 217-225.Danielyan, Yu. S., and Panitsky, P. A., 1979,Neravnovesnye effekty v protsessah promerzanijavlazhnyh gruntov. Transactions of the SiberianResearch Institute of Petroleum Industry, issue47, p. 171-182.Kurzayev, A.B., Qulividze, V.I., and Ananyan,A. A., 1977, Spetsifika fazovogo perehoda vodyna poverhnosti biologhicheskih i neorganicheskihdispersnyh tel pri nizkih temperaturah. Transactions"Svyazannaja voda v dispersnyh sistemah,"issue 4: SCOW, Moscow University Publications,p. 156-166.Osipov, V. I., 1979, Priroda prochnostnyh ideformatsionnyh svoistv glinistyh porod: MOSCOW,Moscow University Publications.Xusanov, A. I., 1967, Fazovyje ravnovesija i poverh-nostnyje yavlenija: Leningrad, "Himija" Publications.Saveljev, B. A., 1971, Fizika, himija i strojenijeprirodnyh l'dov i myorzlyh gornyh porod: Moscow,Moscow University Publications.Yershov, E. D., Akimov, Pu. P., Cheveryov, V. G.,and Kuchukov, E. Z., 1979, Fazovyi sosravvlaghi v myorzlyh porodah: Moscow, I4oscowUniversity Publications.Yershov, E. D., Shevchenko, L. V., and Yershova,G. E., 1974, Vlijanie temperatury na energhijusvyazi gruntovoi slaghi. Transactions "Merzlotnyjeissledovanija," issue XIV: Moscow, MOSCOWUniversity Publications, p. 151-160.

EFFECTS OF VARIATIONS IN THE LATENT HEAT OF ICE FUSION INSOILS ON INTERACTION OF BOREHOLES WITH PERMAFROSTM. A. Anisimov, R. U. Tankayev, and A. D. UlantsevResearch Institute of Petrochemical and Gas Industry21oscow, USSRExperimentally derived values of varying latent heats of fusion of ice (Ab) insamples simulating permafrost over a temperature range -30°C of to 0°C are cited.The value AH , was shown to be heavily temperature-dependent and -5'C at it is morethan six times less than the heat of fusion of homogeneous ice. Calculations of thethermal interaction of boreholes with permafrost have demonstrated that for clayeymaterials adjustments in the calculated radii of warming due to in changes A% mayreach 150-300%.Thermal calculation is a foundation for predictcpling the interaction of boreholes with permafrost.In computer calculations of thermal interaction ofboreholes with permafrost one should take intoaccount that at temperatures below zero, heat conductionof frozen rocks is complicated by watermigration to the frozen front and that heat capacityis complicated by heat of ice fusion being absorbedin the temperature range between 70°C O°C. andSimple estimations show that for the actual frozensoils and rocks in temperature range between -1O'Cand 0°C. 80-99% of heat capacity is determined bythe heat of ice fusion occurringthe rock pores.The heat of ice fusion in the frozen rocks is oneof the most important physical properties thatgoverns, in the final analysis, the choice ofmethods for protecting the structures against harmfuleffects of permafrost.Litvan (1966) was the first to demonstrate experimentallythe possibility of change of icefusion heat in permafrost rocks. Plooster andGitlin (1971), Brun et al. (1973), Berezin et al.(1977) and Mrevlishvili (1979) investigated theintegral heat of ice fusion in disperse systems ofdifferent origins. Their papers show that as themoisture content in the samples decreases, theintegral molal heat of fusion is reduced. When thesamples have a water content corresponding to 1-2effective monolayers the heat becomes equal to zero,However, as far as know, we the data obtained bythese authors were not used for thermal calculationssince it was impossible to relate the integralheat of ice fusion to 'bean" fusion temperature.Figure 1 schematically illustrates a heatcapacity anomaly stemming from the fusion of icemass unity in permafrost rocks. The integral molalhear of fusion is equal to the shaded area boundedabove by the relation curve of molal heat capacityof water in the sample and temperature and below bythe consistent part of this relationship. Accord-7;'ing to more precise calorimetric (Mrevlishvili1979, Anisimov and Tankayev 1981) and dilatometric(Litvan 1978) data the temperature at which fusionstarts is about -70°C for different samples. Gen- FIGURE 1 Schematic relationships between heaterally, a low-temperature branch of the heat capacity (Cp) and liquid water content ($) andcapacity anomaly curve is not a smooth function of temperature (T) in a sample of frozen rock.200

201temperature and may be complicated by the peaks,which are due to either characteristic features ofthe crystalline structure of the mineral rockskeleton (Anderson and Tice 1971) or eutectics ofsalts dissolved in water (Mrevlishvili 1979).Evidently, integral molal heat of fusion is toocrude a characteristic for such a complicated processto take place within a range of some tens ofdegrees.To describe ice fusion in disperse systems theauthors have introduced the concept of differentialmolal heat of fusion (Anisimov and Tankayev 1981)and developed a method of experimental determination.Thermodynamic definition of this value isexpressed as follows:at constant pressure:where (A&)p is the isobaric molal differentialheat of ice fusion in rocks; AH, is variation ofthe soil sample enthalpy due to fusion; T and P aretemperature and pressure; ACp and A~L are respectivelythe excess isobaric heat capacity of thesample due to fusion and the variation of moisturecontent in the sample at AT.Figure 1 schematically illustrates the method ofdeLermination of initial data for the calculationaccording to formula (1) from experimentallyderived relationships between Cp(T) and mL(T),When determining AHm the following conditionsshould be observed:1. Both initial relationships should correspondto the equilibrium state of a sample.2. The condition AT

202///-/ \/ \IaIII 1e-I/III I I 1 I 1 I" I-30 -25 -20 -45 -40 -5 0 TdTJXI LFIGURE 2 Relationship between differential heat of ice fusion (A%), and temperatureT: t-, 0, A represent samples 1, 2, 3 containing 31.6i 4.8; 6.2 grams of water per gramof aerosil respectively (our data). The values for A% have been calculated from formula(2) -ED. Relationship between integral molal heat of ice fusion (am) and temperature ofice fusion completion (T,): o - porous glass (Litvan 1966); a - aerosil (Plooster andGitlin 1971, a - in A1203 (Brun et al. 1973); 0 - DNA (Mrevlishvili 1979).there is only a comparatively narrow temperature essential for engineering calculations. Such rocksrange but the initial temperature of permafrost is include sand and sandstone. For the rocks with therarely -10°C. Besides, mineralization of formation specific surface 10 d/g, however, the thawing zonewater has not yet been taken into account. This is radii, where changes of heat of ice fusion in thea matter for future study.Computers have been used-in the calculation ofthermal interaction of .the borehole with permafrost.The following initial data were taken into accountin the two-dimensional solution for heat conductivity:the borehole is surrounded by a homogeneousstratum of frozen rocks. Density of themineral skeleton is 2.5 g/cm3. Complete water andice content in the rock varies between 30% (byvol.) at the surface to 20% at a depth of 300 m.The initial temperature of permafrost variesbetween -4'C at a depth of 25 m to O°C at a depthof 300 rn. Temperature on the hole wall showslinear variation from 20°C at the well head up to3OoC at a depth of 300 m. In addition, variousseasonal temperature variations at the surface andthe heat flow from the formation have been examinedwith rock specific surface varied.The computations have shown that a correctionto the size of the thawing zones in case of rockswhose specific surface is less than 5 m2/g is notrock have not been considered, are underestimatedby 1.5 times. With an increase in specific surfacethe difference in calculation results increased and,in the case of rocks wirh high clay content and aspecific surface of 30 m2 /g, the thawing zone radiidiffered by 3 times. The calculation program hasallowed computation of both the temperature profilein the vicinity of the borehole and the position ofthe ice fusion front. In the case of particularlyclayey rocks with low moisture content the icefusion front and 0°C temperature profile did notcoincide,Figure 3 illustrates the calculation results ofthe position of the O°C isotherm 1,245 days afterstart-up of the borehole "operation" for a rockspecific surface of 20 mz/g.It is common knowledge that the specific surfaceof clays may attain several hundred square metersper gram of soil. Calculations of thermal interactionsof structures wirh permafrost soils androcks made without considering the actual physical

203\\The conclusion may be drawn that a detailedstudy of ice-water phase transitions in frozenrocks made by modern techniques of experimentalphysics would provide a considerable increase inthe precision and reliability of thermal calculationsin permafrost.REFERENCESL\\\\\\L\\FIGURE 3 Positlon of the computed O°C isotherm1,245 days after the beginning of permafrost rockwarm-up. Solid and dotted lines respectively showthe position of the isotherm with allowance for(A&),(T) and without such an allowance. 2 is theborehole depth (meters); r is the distance from theborehole centerline (meters).pattern of ice fusion in frozen rocks are unrealistic,However, since layers of pure montmorilloniticclays rarely occur, such a case is atypical.atypical.Anderson, D. M., and Tice, A. R., 1971, Low temperaturephases of interfacial water in clay-watersystems, Soil Science Society her. Proc., v.35, p 47-54.Anisimov, M. A., and Tankayev, R. U., 1981, Icefusion near a hydrophilic surface: Zh. Eksp.Teor. Fis. v. 7, p 217-225 (SOV. Phys. JETP,v. 45, p. 110).Berezin, G. I., Kozlov, A. A., Kooznetsova, L. V.,1972, Calorimetric study of capillary condensatephase transition, Surface forces in thinfilms and disperse systems. Moskva, "Nauka"Publishers, p 202-209.Brun, M. M., Lallemand, A., Lorett, G ., Quinson,I. F., Richard, M., Eyrand, L., Eyrand, C.,1973, Chengement d'etat liquidsolid dans lesmilteux poreux: Journal d'Chimie Physique, V.70, no. 6, p 973-978.Kvlividze, V. I., Kurzayev, A. E., 1979, Propertiesof thin water layers according NMR to method.-In Surface forces in thin films: "Nauka"Publishers, p 211-215.Litvan, G. C., 1966, Phase transition of adsorbates,I Specific heat and dimensional changer of theporous glass-water system: Canadian Journal ofChemistry, v. 44, p 2617-2622.Litvan, G . G., 1978, Adsorption systems at temperaturesbelow the freezing point of the adsorptive:Advances in Colloid and Interface Science, v. 9,no. 4, p 253-302.Mrevlishvili, G. M., 1979, Low temperature calorimetryin biological macromolecules: UspekhiFisicheskich Nauk (Sov.), v. 128, no. 2, p. 273-312.Plooster, M. N., and Gitlin, S. N., 1971, Phasetransitions in water adsorbed on silica surfaces:The Journal of Phys. Chem., V. 75, no. 21,p. 3322-3326.Yegorova, T. S., Kvlividze, V. I., Kiseliev, V. F.,Iyevskaya, N. M., Sokolov, N. D., 1963, On natureof silica surface and water bond. &Modernviews on bound water in rocks: Moscow, The USSRAcademy of Sci. Pub., p 35-54.

MASS TRANSFER IN THE SNOW COVEROF CENTRAL YAKUTIAA. L. ArePermafrost Institute, Siberian BranchAcademy of Sciences, Yakutsk, USSROn the basis of ten years of experimental research it has been established that theintensity of mass transfer in the snow pack is temperature-dependent and reaches itsmaximum at snow temperature above -2O'C. The mean rate of vapor diffusion in snowlayers near the base of the pack varies between (2.0-2.5) x g/cm2 per day. The"norms" were obtained for snow sublimation for all types of landscape in CentralYakutia, e.g. 12 mm on meadows; 5.5 mm in pine forest; 6.2 mm in larch forest; and8.5 m on lake ice. The value for mean daily sublimation of snow is determined onthe basis of the air humidity deficit and the wind velocity. Ten-day sublimationtotals were determined on the basis of the absorbed radiation.During the last decade, mass transfer in the the snow Layers at the base of the pack and asnow cover of Central Yakutia has been explored by deep-hoarfrost horizon with a well-definedthe Permafrost Institute of the Siberian Branch of "fibrous" structure develops,the USSR Academy of Sciences in studies of the snow The investigations carried out by Kuvaeva (1972)cover effect in the permafrost thermal regime. Themethods and first results of these investigationsin the Caucasus have shown that the formation anddevelopment of deep-hoarfrost crystals occur a atare reported in Pavlov (1965) and Are (1972, 1978a, rare of aqueous vapor diffusion in excess of 1.3-1978b). The snow cover is regarded as an independ- 1,5~10-~ g/(24 hr.cm2) and a mean air temperatureent natural component in conjunction with the below -10°C. Such conditions are characteristicentire variety of wintertime natural conditions. A of the formation period of the snow cover in thestudy is made of the aqueous vapor diffusion within regions of Yakutia, where only one event a 10- ofthe snow cover thickness, of its surface evapora- day-average air temperature was observed to betion and snow recrystallization processes, result- well above -1O'C in the past decade.ing from mass transfer under naturally occurringconditions.Vapor diffusion measurements have indicatedthat the mean diffusion rate snow in layers at theThere are presently very few in-situ measure- base of the pack varies from (2.0-2.5)g/(24ments o€ the aqueous vapor diffusion rate in thesnow cover: in the European part of the USSR thesehave been made in the Caucasus (Kuvaeva 1961, 1972)hr.cm2) to (3.0-4.0) g/(24 hr.cm2), dependingon soil moisture and weather conditions during thecold season. The mean diffusion rate, as measuredand in localities near Moscow (Pavlov 1965), where- in Western Siberia (Kolomyts 19771, is of the sameas for continental regions which are characterized order of magnitude, but varies over a wider rangeby longer snow cover, only data obtained in Trans- from (1.5-2.5) to (3.5-5.0) g/24 hr cmz),baikalia (areas south of Lake Baikal) and WesternSiberia are available (Kolomyts 1966, 1971)Near Mt. Elbrus the mass transfer rate is significantlylower (Kuvaeva 1972), and its maximum, equalExperimental measurements of snow sublimation to 3.0 g/(24 hr-cm2) was observed only duringare considerably more numerous. These have beencarried out in various physiographical regions.Empirical formulae have been derived for sublimationassessment. But as far as Siberia and theNorth-East of rhe USSR are concerned, the data arestill very meager. However, in such drought-riddenone of five winter seasons during the period low- ofest air temperatures.It is known that when the snow's temperature iscomparatively high, a thin quasi-liquid layer isformed on the surface of its crystals, whosemolecules have considerable mobility (Ushakova etareas as Central Yakutia the determination of snow al. 1968). By increasing the snow's temperaturesublimation losses is of vital importance forcalculating water resources.Years of stationary observations have revealedthat in Yakutia the shallow snow cover is characterizedby a high degree of recrystallization,the thickness of this layer increases and themolecular mobility intensifies; under such conditionsthe rate of sublimation-induced growth ofcrystals also increases. The maximum rate of sublimationrecrystallization is probably a in tempduringwhich in a very short time the greater part erature range of from -5 to -15°C. The temperaofthe snow depth (up to 70-90%) assumes a deephoarfroststructure (Are 1972). Deep-hoarfrostcrystal formation begins in the early days of theformation of a stable snow cover, whose densitydoes not exceed 0.09-0.13 g/cm3. It assumes acontinuous course and within 3 or 4 weeks therure-dependence of the snow cover recrystallizationrate was confirmed through experimental observationsin Khibiny Mountains (Savelyev et al. 1967).A relationship between the vapor diffusion rate anthe snow cover temperature was found also a instudy of mass transfer in the snow cover of Westernoriginal snow structure disappears completely in Siberia, where at snow temperatures below -1O'C the204

205TABLE 1 Intensity of Water Vapor Diffusion i * g/(24 hr * cm2) and Thermal Properties ofthe Snow Cover in the Winter of 1976-1977PeriodtAtIAzh=5cmAti t i tAzIn a larch forest (near a lake)23-29 Dec -31.2 1.4 2.0 -35.1 0.s 3.4 -33.6 1.0 2.622 Dec-2 Jan -33.4 - 1.9 -33.2 0.6 1.6 -33.6 0.7 1.32 Jan-10 Feb -28.0 0.9 1.9 -31.3 0.7 1.7 -30.2 0.7 1.610-20 Feb -26.2 0.5 2.5 -26.8 0.4 2.0 -27.2 0.3 1.920 Feb-1 Mar -26.8 0.5 2.0 -27.1 0.5 2.3 -30.2 0.5 0.81-10 Mar -27.4 0.4 2.7 -26.0 0.4 2.0 -27.0 0.4 2.0-AtInzih=lOOn ice ofa lake23-29 Dec -18.7 2.0 14.1 -19.4 2.2 19.0 -27.8 1.8 8,329 Dec-2 Jan -25.2 2.2 7.4 -26.2 0.9 6.9 -29.6 1.4 4.22 Jan-10 Feb -22.6 1.6 7.2 -18.9 1.5 7.3 -22.5 1.2 5.310-20 Feb -14.6 0.9 18.3 -16.8 1.2 18.2 -1E.6 1.4 12.620 Feb-1 Mar -15.7 0.8 18.3 -14.9 1.1 21.4 -17.6 0.9 13,O1-10 Mar -17.3 1.4 12.9 -14.3 1,4 5.6 -20.3 0.9 8.0Note: t is the mean temperature of snow layer ("C) in which diffusion is being measured;AtIAz is the temperature gradient of this layer ("C/cm).increase in the mass transfer rate was detectedonly up to gradients of 0.55-0.60 "Clcm. Athigher differences in temperature the diffusionrate is practically independent of the temperaturegradient (Kolomyts 1977).The most favorable conditions of mass transferare created within the warmest near-soil snow layer,where the vapor concentration gradient is greatest.The mass transfer rate in the snow cover decreasesboth with height and in the process of subsequentsnow cooling during the winter insofar as therecrystallization rate is determined not only bythe temperature gradient, but also by the temperatureitself.The highest rate of mass transfer in Yakutia wasmeasured in the snow cover on lacustrine ice(Table 1). The obtained data show that in the snowcover at a level of 5 cm above forest soil theaverage winter diffusion rate comprises 2.2gl(24 hr-cm2). At the same level in the snow coveron lacustrine ice it comprises 13.0 g/(24 hr.cm*), i.e. six rimes the former, In addition, thewinter-average temperature gradients in the samesnow layer are 1.4'C/cm on the lake and O.G"C/cmin the forest, i.e. they differ by a factor of 2only, Such a high rate of mass transrer is due tothe warming effect of a lake not frozen to thebottom. The temperature in the lower snow layerhere averages about 8-10°C higher than in the samelayer in the forest and on individual days thisdifference reaches 12-15°C. The relationshipbetween the water vapor flow rate and the snowcover temperature is shown in the diagram (Figurel), according to which a significant increase inthe rate takes place at snow temperatures above-20°C. Figure 2 shows vapor diffusion rate versustemperature and temperature gradients. The largestrate of diffusion flow at the same temperaturegradients, as follows from the diagram, correspondsto the range of lower snow layer temperatures from-6 to -15°C.20 ~Io -FIGURE 1 Vapor diffusion intensity as a functionof snow temperature based on depth.I - on lake iceI1 - on the shore of a lakeDuring the winter of 1976-1977 (from 4 Octoberto 14 March) 0.430 g/cm2 of material was carriedaway from the soil surface of a dry glade whilethat removed from a snow layer 10 cm high abovesoil-top amounted to 0.209 g/cm", i.e. 2 timesless.Years of observations of snow sublimation haverevealed a high annual variability in the totalamount, associated with the annual variability ofthe weather. A norm of the snow sublimation ratehas been obtained for all the basic types of landscapeof Central Yakutia. For wide-open, forestfreeregions it is about 12 mm or 16% of the amountof solid precipitation during the cold season. Insome years the evaporated amount of moisture canexceed one-quarter of the entire winter moisture

206i. 10 -344 48 1,Z 1,6 2,O & ,OC/crnAZFIGURE 2 Relationship of the water vapor diffusionintensity i iith temperature and temperaturegradient At/Az in a snow layer 0-10 cm thick.The range of negative temperatures is: I - 30-35'C,I1 - 24-29'C, I11 - 18-23"C, IV - 6-15'C.storage, i.e. it can substantially diminish, inthe overall budget, the contribution from solidprecipitation to melt flow and soil imbibition.Sublimation under the canopy of a pine forest isless than in open areas by a factor of 2.5.In a larch taiga the sublimation in closedglades averages 9.7 mm while under a forest coverwhose canopy is less dense than that in a pineforest due to the shedding of the needles, it isless by a factor of 1.5. The snow Sublimation onthe lacustrine ice surface is 36% less than thatin a glade that stems from air thermal inversionthe deep basin of the lake.The seasonal variation of snow sublimation, whihas been studied using daily measurements, demonstratesthe following features. In the coldestseason from the beginning of winter rill mid-Marchthe sublimation intensity is low which is associatedwith the low temperature of the air and, subsequently,the snow cover's surface. From thesecond half of March the air temperature risesappreciably and snow sublimation intensifies. Forthe last 10-day period of March it constitutes 60%of the monthly total, or 1.9 nun. In April thesublimation rate continues to increase and its10-day-averaged sums are 2.7, 3.7, and 5.3 mu.Figure 3 shows a plot of sublimation intensityversus ambient temperature. The rather highrelative humidity and a weak wind, which charac-terize Yakutia winters, result in the lowest sublimation(curve 1). As the ambient temperatureFIGURE 3 Relationship of snow sublimation with ambient temperature, daily mean relative humidityof air W(%) and daily mean wind speed V (m/s).1 - W = 60 - 75% V = 1 - 4 mls2 - W = 50 - 59% V = 5 - 6 m / s3 - W 50% V > 6 m/s

207increases there is an increase in snow's surfacetemperature and the humidity gradient of the airlayer closest to the surface layer rises whichleads to increasing sublimation. Within the rangeof air temperatures from -20 to O°C the sublimationrate is greater, the lower the relative humidiryand the stronger the wind (curves 2 and 3). Thefigure shows that the best conditions are createdat air temperature above -10°C.The data from 190 daily measurements of evaporationfrom the snow surface have been used to obtainthe empirical relationshipE = (193 + l8V) * * d, (1)E = 72 * - 0.927, (2)mental methods of determining the evaporationwhere E is the 10-day total of evaporation, m;from the snow cover surface. Proceedings of theQn is the 10-day total of the absorbedFifth Transcaucasian Scientific Conferenceradiation, cal.the Study of Snow Cover, Snow-Slips and GlaciersThe correlation coefficient of this relationship of the Caucasus: Leningrad, Gidrometeoizdat, p.is 0.74 kO.11, The calculation error for the 10-day 25-43 (Proceedings of the Transcaucasiantotal sublimation, as compared to the measured sum, Hydromet. Research Inst., V. 58).is k0.16 mm.Pavlov, A. V., 1965, Heat exchange of freezing andResearch results indicate that despite extremely thawing earth materials with the atmosphere:severe climatological conditions the intensity of MOSCOW, Nauka, 254 p.mass transfer is high in the snow cover of Central Savelyev, E. V., Laptev, M. N., Lapteva, N. I.,Yakutia. The temperature of the snow cover itself 1967, Structure, composition, physical-andmakes a crucial contribution to this process. Amechanical properties of snow in Khibinylong-term "normal" of sublimation from the snow Mountains and their variation in the processcover surface has been obtained for the major typesof landscape in Central Yakutia: wide-open areas,coniferous and larch forest, lacustrine ice. Anempirical relationship between the daily meanevaporation of snow and the humidity deficit of airand wind in addition to the relationship between aconnection of 10-day Sublimation totals and absorbedradiation have been established. These, then,can be used to calculate the water balance.REFERENCESAre, A. L., 1972, Evaporation and evolution of thesnow cover in localities near Yakutsk. InExperimental investigations of mass tranzerprocesses in frozen rocks: Moscow, Nauka,p. 160-167.Are, A. L., 1978a, Snow cover of Central Yakutia,properties of its radiation and hydrothermalwhere E is the sublimation rate from the snowregime. In Heat exchange in permafrost landsurface,mm/24 hr;scapes: Yakutsk, p. 30-42.V is the daily mean wind speed at 17 m Are, A. L., 1978b, Experimental investigations ofaltitude, m/s;the hydrothermal regime properties of the snowd is the daily mean deficit of air humidity, cover of Central Yakutia. GeothermalphysicalPa.investigations in Siberia: Novosibirsk, Nauka,The correlation coefficient for the relationship p. 41-47.obtained is 0.75f0.05. The error of determination Kolomyts, E. G., 1966, Snow cover of mountain-taigaof sublimation value by the formula (1) as compared landscapes of the North of Zabaikalia: Yfscowtothe measured value is iO.01 mm/24 hr.Leningrad, Nauka, 183 p,According to analysis of the existing regional Kolomyts, E. G., 1971, Structure and regime of theformulae, made by Kuzmin (1974), errors in calcu- snow cover of the West-Siberian taiga: Leninlationof the value for daily snow sublimation are grad, Nauka, 174 Q.on the average 2-3 times greater than those of its Kolomyts, E. G., 1977, Methods of crystallomorphoin-situmeasurements. However, as the time interval logical analysis of snow structure: Moscow,increases, the errors decrease. Therefore formula Nauka, 198 p.(I), like other regional formulae, may be recommend- Kuvaeva, G. M., 1961, Water vapor migration anded for calculation of the mean sublimation rate for structural changes of snow. Proceedings of theextended periods, a ten-day period, a month, and First Transcaucasian Scientific Conferencemore.the Study of Snow Cover, Snow-Slips and GlaciersDuring the typically radiant spring weather in of the Caucasus. Proceedings of the TbilisiCentral Yakutia, when because of fair weather with Hydromet. Research Insr., v. 9: Leningrad,some clouds and the high transparency of the dryGidrometeoizdat.air the solar radiation intensity is very great, Kuvaeva, G. M., 1972, The conditions and timethe absorbed solar radiation plays a decisive role required for deep hoarfrost to evolve in a snowin snow sublimation and melting, In analytic termsthis relationship can be roughly expressed as:cover. In Proceedings of the High-AltitudeGeophysizl Institute, v. 18, "Snow and snowslips":Leningrad, p. 61-70.Kuzmin, P. P., 1974, On the calculated and experi-of metamorphism. & Snow and avalanches ofKhibiny Mountains, p. 201-239.Ushakova, L. A., Kvlividze, V. I., Sklyankin, A.A..,1968, Advances in Science. Hydrology of dryland, glaciology: E~SCOW, VINITI.

POSSIBLE APPLICATIONS OF FOAM CEMENTS IN PROTECTING THEENVIRONMENT IN CONNECTION WXTH WELL DRILLINGV. BakshoutovResearch Institute of Petrochemical and Gas IndustryMoscow, USSRThe article presents the results of investigations into the application of crystallochemicalintensification of the oil-well foam cements of the "Aerotam" type (aeratedplugging material.) with densities of 800 to 1600 kg/m3 and thermal conductivities of0.35 to 0.55 W/m2 OK at temperatures from -lO°C to +160°C. It demonstrates thatcement slurries of the "Aerotam" type may find wide industrial application for protectingthe environment in well construction and as "passive" thermal insulation forcementing the casings of oil and gas wells in permafrost areas, and also a super- aslight plugging material for cementing casings under conditions of abnormally low wellpressure and intense grout absorptions. Thawing of the permafrost during drillingand operation of wells in oil and gas condensate fields leads to irreversibleecological damage. Various methods of "active" and "passive" thermal protection areused; to prevent such thawing,either case practice has shown that the bestresults have been achieved by the application of special plugging materials withhigh thermal insulating properties, namely foam cements, for well cementing.In 1974 €or the firs It time we oh ltained a pluggingfoam cement slurry with density of 800-1300kg/m3 and thermal conductivity factor 0.35 ofW/mZ0K, which normally hardened at temperatures aslow a5 -10°C with the formation of the cement stone,which after two days of consolidation had a bendingstrength of from 0.3 to 1.2 MPa (Bakshoutov 1976,1977).Further work made it possible to modify foamcement slurries of the "Aerotam" type for low andhigh temperatures. Composition, properties, andthe results of pilot studies under different conditionsare cited in the works (Bakshoutov 1977-1981)Plugging foam cement slurries consist of thefollowing components:1. Mineral viscous-commercial products orspecial oil-well cements and mixtures for specificapplications.2. Liquid for mixing the cement-calciumalkalinitysolution (K,C09 + KOH) for low temperatures,salinated water and drilling mud for hightemperatures and salt aggression.3. Liquid emulsifier (foamer)-SAA (surfaceacting agents) or surfactants of the alpha-olefinsulphonate or "Afrox-200"(USA) type, and alsosulphanol, liquid soaps, thermoresistant SAA (forexample, polymetilensulphometilen-phenolate natrium,alkylethoxylated sulphate) and others, that areselected based on the type of mixing liquid and thethermal conditions to provide the foaming of theslurry and to obtain a stable foam with high foamquality and compressive strength.4. Hard emulsifier (the foam stabi1izer)"synthetic(aerosil, butoxy-aerosil) and natural (mould,flask, tripoli) preparations of silica with highdispersion ability, and various mud powders. Inaddition, it stabilizes the bubbles air of in thecement slurry.5. The pores colmatater-the polymer silic-organic - liouid of the HSW-tvae .(used in calcium- aalkaline medium), silicate soluble or kasein (forwater and mineralized liquids for cement mixing).It colmatates the permeable capillary pores in thestructure (texture) of the cement stone.6. Air (Bakshoutov 1976-1981) or nitrogen(Montman 1982)"to decrease the density of theslurry and of the cement stone.To obtain a highly stable foam cement slurry andto optimize its composition a Box-Wilson experimentis conducted, which, with a total number of testsn=16, makes it possible to describe the mathematicalmodel of the process and to find its optimum.As the optimization parameter the Sp-stability offoam cement slurry-was used. For the lowtemperature"Aerotam" modification the adequateregression equation looks likey = 89.9~~ + 2.88xl + 1.13~2 + 4.63~3 t0.38~9 + 2.13~1~2 - 0.38~1~3 - 1.63~1~4;X1X2 = X3X4; XlXgX2X4; XlX4 = XzX3,where y = parameter of Sp in %;xo, XI. x2. xg, x4 = concentration of cement,of calcium-alkalinitysolutionforcementmixing,of liquidandof hard emulsifiers, and ofthe polymericadditive, in mass %.Planning which was done shows that to obtain afoam cement slurry with = Sp 100% its compositionmust include:5% water solution of calcium-alkalinity solution(K2C03 + KOH); 0.5% of liquid, 0.05% of hard emulsifiers,and up to 0.9% of the polymeric additive.The results of research on the relationshipbetween the strength of the foam cement stone andits density, processed with the assistance of a"Vang-2200" micromodule computer according to the"Basic" programme, showed that the curves are208

209described using an equation of the second degree:-u = a0 + alp + a2pL ,where is the compressive strength, in MPa and pis the density of the cement stone, in kg/m3, witha reliability equal to 0.93-0.99; the coefficientof correlation (correlation factor) is equal to0.96-0.99.Research on the water absorption kinetics of thefoam cement stone has shown that the samples withthe polymeric additive of the optimum compositionhave a water absorption factor about three timesless than the same samples without the colmatatingadditive, which helps the stone keep its goodthermoinsulating properties in the well both duringdrilling and while the well is in operation.The most important characteristic of the foamcement is its structural porosity, i.e. the distributionof pores in the volume of the cementstone according to their sizes, mainly influencesits strength, permeability, thermoinsulating properties,etc.The study of the structural porosity of the foamcement stone by measurement of mercury porosity atlow and high pressure shows that the increase ofhardening pressure decreases the total porosityfrom 79 to 55%.Analysis of the research results allows us todistinguish three groups of pores: oimpermeablemicropores with a radius of 50-SO0 A, medium radiusof 500-10,000 A, and the permeable micropores witha radius of more than 10,000 As the hardeningpressure increases, the volume of impermeable microporesgrows, and the volume of the medium-radiuspores and micropores drops (Table 1).will freely communicate, forming easily permeablemicropores and channels 10 to 18 urn in size. Aldrichand Mitchell (1976) define their range of useby the magnitude of foam cement porosity with theinclusion of surfactants: Highly porous withrelative porosity more than 52% are well permeablefor liquid and gas can be used for plugging thebottomhole zone of sand-drifting (sand-flowing wells;cements with Low porosity where the capacity for bubblecommunication is low may be used for cementingcasings.As the foam cement hardens, its permeable microporesbecome covered with the products of newhydrate formations, and the stone's permeabilitydrops. To provide minimum permeability in theearly stages of hardening it is necessary to addthe modified additive to the foam cement slurrythat colmatates the opened pores in their partitions.In the "Aerotam" low temperature slurry,a silicate-organic liquid is used that rapidlypolymerizes in the alkaline medium of the cementmixing liquid.The formation of the permeable macropore proceedsin such a way that after 12 hours of hardening itis 6 pm in size and may be filled with freecapillary water. Over time the pore becomes coveredwith products oi silicate-organic liquid polymerizationwith silica gel gelation and topochemicalsedimenting.To determine the nature of the interconnectionbetween the size of pores in the foam cement stoneand its main properties (Table 2) (density p,porosity &, permeability K. the bond force withmetal zc, and heat conductivity factor 1) the liparameter is used, which is a relatively mediumpore radius.TABLE 1 PorosityTABLE 2The foam cement propertiesP & r1 >(Mea) (X) 104A103br3 1O2brb104W>r2>103A >102iI >50iR 3 ?jC. 10 ~-10-l~ P x(ma) (MPa) (ma) (mZ> (kg/m3> (BT/rn*%)3.0 5s 30.22.0 58 33.61.0 64 44.20.5 6a 45.70.1 69 56.921.0 35.4 13.426.0 28.4 12.414.9 29.5 11.423.2 22.1 9.016.0 21.4 5.73.0 3.66 2.4 1.5 1380 0.592.0 3.35 2.2 3.4 1290 0.531.0 2.30 0.8 5.6 1113 0.450.5 1.58 0.6 5.5 980 0.380.1 2.70 0.5 4.9 960 0.36This provides €or the formation of a denser ce- The results of the computer data processing showment stone StrucKure with increased strength andthat changing of On-stone properties P, 8, FC, Kdecreased permeability.from R are described by means of square (y = qaThe structure of the foam cement stone was also QIX + Q2x2), and E and A - linear (Y Qg+Qlx! funccomprehensivelystudied by raster and translucent tlons; the correlation factors are correspondinglyelectron microscopy to obtain the photos of theequal to 0.98-0.99 and 0.95-0.99 (Table 3).pores with high depth and image definition.Air pores of the foam cement stone arranged inTABLE 3 The regression equationsthe volume of hardening system are separated byviscous partitions of varying thicknesses, from 1.5G: 90 Q1 42 KKpm and less, up to the thickness of the particlesof hard emulsifier and the surfactant adsorptionlayer.P -10.75 6.18 -0.79 0If the liquid film of the foamer covers theE - 0.46 0.25 - 0.99surface of an air bubble immediately after the foamKcement is mixed, then during further hydration of -23.3 -15.62.6 0.98U 19.9 34.6 -7.6 0.99mineral particles its thickness may gradually-40.9 23.2 -3.1 0.99decrease until it disappears, when the air pores ZCx 1.41 -0.25 - 0.95

210The regression equations that describe the injection of hot agents, etc.).interconnection between the given parameters are The properties listed above indicate that foamcitedin Table 3. By controlling the size of pores cement slurries are a promising substance for wellin the foam cement stone it is possible to change construction and drilling from the standpoint ofits main technological properties in order to solve environmental protection.serious tasks.The low-temperature modifications of "Aerotam"The good technological properties of foam cement foam cements were successfully applied in 1977-stone are mainly due to the phase composition of 1983 for cementing surface casings in oil and gasthe minerals that form it.wells in the permafrost rocks in the fields of thThe phase composition of "Aerotam" foam cement North of Tyumen region, and Yakutia. Highatonediffers from usual types in the following: temperature "Aerotam" modifications were success-1. Due to the potassium alkaline mixing liquid fully employed for cementing intermediate anda great number of OH- ions are introduced into the production casing stringshigh-temperature/ oilhardening system which form: stable lowbasic hydrosilicates of calcium of tobormarite group of theCSH (B) type, composed of [ CaO,. (SiO, l (H2 O),] ;potassic hydrocarbonates of the [Kr.H2fCO3), a 1 . 54Oltype;potassic-calcium hydrocarbonates [K, -Ca(COS Is ] *2 +.5H20; potassic-calcium hydrocarbosilicates[K,O~CaO*CaCO;nSiO,]*aq; potassic hydroaluminosilicates[x(K20*A1,0,)*ySi02*zH,O]; andcalcium hydrocarbonates [CaCOs6H20-2KOH], whichprovide the stone with high strength both duringthe early and latter periods of hardening,2. The presence of highly polymerized siliconoxygenradicals [Si-01 leads to Si-0-Si connectionsin the alkaline medium in the presence of organosiliconcompounds and synthetic silica agents,which are the "catalysts" for the polymerizationof the silicon-oxygen radicals of the [Si6017]10;aq, [Si12031]14-. aq and [Si6015]~-- aq types.Highly polymerized silicon-oxygen radicals arethe basic structural units of low-basic hydrosilicatesof calcium of the tobemarite type Calo[Silz0311. (OH)6'8H20 (riversideite, plombierite),ksonotlite Ca~'[Si6017]'(OH), (gyllenbraadite,phoshahyte) and gyrolite Ca~'[SisOls].(OH);4H20(ocenite, necoite, truscotitel-the main inducersof cement stone strength."Aerotam" plugging foam cement slurry and thestone derived from it are characterized by thefollowing technological properties: protection ofthe mixing liquid and of the cement slurry fromfreezing; the technologically necessary period ofcement setting and time of cement thickening; anormal schedule for cross-linking and the develop-ment of durability, high strength, adhesivenesswith permafrost rocks and low permeability of thefoam cement stone; protection of permafrost rocksfrom thaw for up 6 to months during constantdrilling and up to 3 months during well operationas compared to 1-2 months with the common pluggingcements; decreased, specifically optimum, heatrelease during cement hydration, conservation ofheat of the producing fluid and hydration prevention;improvement of the degree of mud expulsion;an increase of cold-resistant factor; absence ofcorroding effects on the casing metal; the possibilityof employment of standard cementing equipment;pumps and compressors of the usual rigequipment.The "Aerotam" foam cements can be used underconditions where other plugging materials don'tprovide quality well cementing (considerable strataabsorption, underlifting of the cement slurry tothe wellhead, plus and minus temperatures, saltaggression, zones of abnormally low pressureformations, the necessity of heat conservationduring well fluid and thermal flow and theand gas wells in Turkmenia fields under condltionsof high mineralization and abnormally low formationpressures (Bakshoutov 1976-1982).In all cases of the "Aerotam" applicatio noecological damage to environment, characteristicfor these regions, caused by human interferencewas observed.REFERENCESAldrich, C. A., and Mitchell, B. I., 1976, Strength,permeabilities and porosity of oilwell foamcement:Journal of Engineering for Industry,v. 98B, no. 3, p. 1103-1106.Bakshoutov, V. S., and Danyushevsky, V. S., eds.,1976, Possibility of application of surfactantbasefoam-cement €or well cementing, & Proceedingsof the Seventh International CongressSurfactants, Moscow, Neftianoye Khoziastvo, no.7, p. 48-50.Bakshoutov, V. S., 1977, On the possibility ofcrystallochemical intensification of the foamcement slurries hardening processes: Moscow,Neftianoye Khoziastvo, no. 11, p. 16-19.Bakshoutov, V. S. et al., 1980, Author's certificateof the USSR, N726306: Biulleten IzobreteniySSSR, no. 13.Bakshoutov, V. S. et al., 1982, Author's Certificateof the USSR, N927973: Moscow, Biulleten IzobreteniySSSR, no. 18.Bakshoutov, V. S. et al., 1978, The experience ofthe conductor casing cementing with "Aerotam"foam cement: Moscow. Neftianoye Khoziastvo,no. 6, p. 53-55.Bakshoutov, V. S. et al., 1979, The application ofstandard equipment for conductor casing cementingwith the plugging foam cement: Moscow,Neftianoye Khoziastvo, no. 1, p. 58-59.Bakshoutov, V. S. et al., 1980, The application oflightened foam cement slurry for the hightemperaturewell cementing: Moscow, NeftianoyeKhoziastvo, no. 7, p. 70-74.Bakshoutov, V. S. et al., 1981, Design andresearch of the plugging foam cements forvarious conditions of application: Moscow,Neftyanoye Khoziastvo, no. 6, p. 22-27.Montman, R. ed., 1982. Low density foam cementssolve many oil field problems: World Oil,V. 194, no. 7, p. 171-186.

INVESTIGATION OF AREAS OF ICING (NALED) FORKATION ANDSUBSURFACE WATER DISCHARGE UNDER PERMAFROSTCONDITIONS USING SURFACE GEOPHYSICALTECHNIQUESS. A. Boikov,’ V. E. Afanasenko,’ and V. H e Timofeyev’lGeology Department, Moscow State University2All Union Research Institute for Hydrology and Geology, Northern RegionsMoscow, USSRThe article identifies the major tasks by faced the permafrost hydrologist in areasof icing (naled) formation and of subsurface water discharge, using surface geophysicaltechniques. A comparative evaluation of the possibilities and potentialusefulness of various geophysical methods, both traditional and modern, is attempted.The peculiarities of geophysical procedures under varying conditions, both winter andsummer, are discussed and methods of integrating various geophysical methods areconsidered.The areas of icing (naled) formation and the Olekminsky cryohydrogeological deep freezing massif,discharge of different types of subsurface water medium and small icings are grouped near the mineralconstitute the principle object of inquirywater sources of deep subfrozen ground drainage. Apermafrost-hydrogeological investigations. These great number of large and medium-size icings occurstudies provide extensive data on the present sub- in the Dzhugdzhuro-Stanovaya hydrogeological region,surface drainage, hydrochemical characteristics of particularly in the so-called Unakhinsky hydrosubsurfacewater formation, its interaction with geological massif of spotted PFR distribution.perennial frozen rocks (PFR) and ultimately facili- The icing types and groups were classified accordtateestimation of subsurface water resources. ing to the results of aerovisual observations andDuring long-term, comprehensive, frozen ground landings on the most typical naled formations. Thehydrogeological and geological engineering studies activities of the landing parties were aimed atwithin the development zone of the central Baikal- identifying the regularities of naled formation;Amur Railway, methods of surface geophysics were typification; bstimation of thickness, areas andwidely used to study the areas of naled formation amount of ice accumulation in the ice crusts;and subsurface water discharge since they were locating subsurface water sources and hydrochemicalconsidered to be among the most informative, pro- sampling using shallow test drilling and extensiveductive and cheap means of comprehensive analysis. geophysical exploration.During preliminary analysis most icings in the Geophysical investigations in areas of naledtest territory were mapped using space and aerial formation and subsurface water discharge are aimedphoto-surveying data, and classified by genetic at solving such permafrost-hydrogeological surveytypes. The icing types were classified in greater problems as identification of talik boundaries, indetall during subsequent comprehensive field stud- which the areas of subsurface water discharge areies. The icings were differentiated according to confined; detection of concentrated subsurface waterthe sources of the subsurface water, the time of discharge areas within them, of dislocations with aformation, the size of icing glades, their shape, break in continuity or high jointing zones, to whichand the amount of ice accumulation. The icings of the water-show areas are usually confined. Thesewater in the seasonal thawing layer (STL), of ground are used to study the structure and thickness ofwater in blind subchannel and sublake taliks, of taliks the and perennial frozen rocks framing thesepressure water of subfrozen ground drainage, and taliks, etc. Icing studies also include identificafinally,ice crust of mixed recharge on account of tion of ice crust thickness, the structure andthe ground water of blind subchannel and sublake condition of the bedrock by investigation of theirtaliks and pressure water of the subfrozen ground interrelationship with taliks, etc. To solve thedrainage were distinguished.problems listed above we used various traditionalConsiderable accumulations of big and huge icing and modern methods of geophysical research. Theyfields were recorded within the Usmunskaya and Chul- included electrometry, electro-prospecting, fremanskayaMesozoic depressions, the Aldan shield and quency techniques, seismic survey, magnetometrynear the North Stanovaya overthrust zone. In the and radiometry,Baikal-Charskaya hydrogeological region, huge icing It would be useful to begin geophysical explorafieldsare concentrated in the Udokan cryohydro- tion of the test areas, using the least labourgeological,deep and superdeep freezing massif, as intensive, most productive methods capable of providwellas throughout the Imangrskaya and Tas- ing operational data about the planned distributionYurekhskaya regional fracture zones. In the Daurs- of the water discharge taliks and concentrated subkayahydrogeological region, particularly in the surface water discharge areas, to provide specific21 1

212hydrochemical samples of the subsurface watersources and information on the geological-pennafrostand hydrogeological conditions, which canlater be studied using more labour-intensiveand comprehensive geophysical techniques. Traditionalgeophysical methods such as longitudinalelectroprofiling (most frequently two-differentialsymmetrical EP) and resistivimetry are themost widely used techniques in the initial stageof investigation (Dastovalov et al. 1979).Longitudinal profiling in the areas of naledformation is conducted along available streamchannels, since experience shows that thedevelopment of through taliks is most probable.The electroprofiling is conducted along the waterline, while for shallow streams and the channels itfollows the bends, crossing the headbands of theicings or subsurface water sources discoveredearlier. Thus, in the areas of subchannel talikicings the electroprofiles are established eitheralong the primary channel or along several channels, meters are used to detect the sources of subaqueousexiting beyond the outline of the naled formation discharge under deep river and lake basins.area. In the areas of flange and slope icing ofsubfrozen ground drainage, longitudinal profilingIn order to conduct traditional electroprofilingfor permafrost-hydrogeological studies in the icingis usually done from the primary river bed up the areas, natural field (NF) electroprofiling, whichstream running along the icing area and exitingbeyond its boundaries. In studies of those icingallows more accurate interpretation of other EPtypes and supplementary information on the zones ofareas, potentially related to the drainage of water subsurface water charging, movement and discharging,from mountain lakes located in upper valleys, the has been tested. an the whole, the informationelectroprofiles are established beginning with the value of this method is not very high and it servesshallow lake waters or the water line in the direc- only an auxiliary function in the overall electrotionof suspected drainage through the icing area, prospecting operations.etc.According to the results of longitudinal profil-In addition to traditional profiling methods usedin geophysical operations, more modern methods ofing, the areas of permafrost development are suf- electroprospecting, such as DEW (dipolar electroficientlydistinguished at ice crust base, well as magnetic profiling) and HFEP (high-frequency elecasthe through and blind taliks formed under the troprofiling), have been tested. A substantialstreams (Figure 2b). Preliminary analysis of the advantage of these methods, as compared with conresultsof longitudinal profiling is followed bythe establishment of individual non-extended transventionalEP, is their higher mobility combinedwith lower labor requirements (a team of 2-3verse profiles through the discovered taliks to persons); this is important for the large-scale anddelineate the taliks in the plan. Resistivimetrydata from longitudinal profiling, which providesinformation about the planned location of subsurfacetime-limited operations carried out in the zone ofBaikal-Amur Railway. The noncontact measurementmethod, which ensures the application under specifiwater sources, are used for the efficient distribu- conditions in areas of large-block deposits (stonetion of these profiles,streams, stone taluses and polygons, etc.), onResistivimetry, one of the most productive and surfaces covered with ice bodies and particularlyinformative geophysical techniques, makes it in operations carried out in winter, is equallypossible to distinguish among numerous occurrences important.of water in the test areas the ones that are related The experience of DEW application in differentto subsurface water discharge. It allows more spe- geological-frozen conditions is on the wholecific hydrochemical sampling, significant reduction indicative of its lower information content andof hydrosamples and preliminary estimation of the resolution as compared with EP the method usingrate of subsurface water mineralization (Afanasenko direct current. Using DE" data, the position ofet al. 1974).different geological and permafrost boundaries inDuring the permafrost-hydrogeological investiga- the plan can be identified, but the qualitativetions carried out in icing and subsurface water interpretation of these data is impeded. Otherdischarge areas, resistivimetry is carried out not substantial disadvantages of the method are theonly as point measurements of individual sources high screening effect of the thawed rocks, whichand other water manifestations (as an auxiliary makes it impossible to use it for studying deepmethod of hydrochemical sampling) but also as a taliks, and the strong dependence of the measuredvariation of stream electroprofiling. In this case values on the earth's surface relief, which resultsresistivimetry, like longitudinal profiling, is in false anomalies, unrelated to the geologicaldonecontinuously along the stream channels, exit- permafrost characteristics of the section. Foring beyond the icing area. Well differentiatedcurves of resitivimetric profiling (Figures 1 and2),which distinctly fix the sites of concentrated subsurfacewater discharge against a total backgroundof depleted solutions, can be obtained. The rateof mineralization of the surface, subsurface andmixed stream waters, together with the relativeoutput of subsurface water sources and a number ofother evaluation data, can be obtained using simplecalculations derived from these curves. Resistivimetricprofiling of a series of profiles having adense river network makes it possible to trace theflooded zones of individual fractures and tectonicdisturbances. These problems are more successfullysolved by magnetometry (Figure 2).Resistivimetric observations are carried outusing special portable meters based on combinedinstruments or electrothermometers and water scoopswith built in 4-electrode units (for water resistancemeasurement) and thermometers or thermo-resistors (for temperature measurement). Theresults of temperature measurements are used forqualitative estimation of surface and subsurfacewater mineralization rate and for their moreefficient identification. Benthonic resistivi-these reasons the DEMP method has not been usedindependently, but as an auxiliary method combinedwith other methods of electroprospecting.The HFEP method, elaborated in VSEGINGEO andtested earlier in Western Siberia (Timofeyev 19771,

213IO000 ""! Ornrnp -e-..ommFIGURE 1 A comparison of the results of different geophysical operationsperformed in winter (a) and summer (b,c,d) periods in the icecrust formation area in the valley of the Kabaktan a river: - pefgraphs of HFEP electroprofiling, b - graphs of pk of symmetrical EPelectroprofiling, c - graphs of Hz/% of dipole profiling DEW,d - graph of resistivimetry, specific electric water resistancesin terms of conventional units; 1 - snow, 2 - ice, 3 - frozen rocks,4 - seasonal-frozen rocks, 5 - subsurface water sources.

214h5 1 Ghtsd501t-c40 L290n. i. I3102903:m kIPm320a7.(*wXI 14Is!PFIGURE 2 Graphs of resistivimetry, thermometry, and magnetometry ofwinter geophysical operations in the area of thermal subsurface waterdischarge in the valley of the Olekma river: a - schematic profilelayout; b - water temperature in the riverbed (1) and spring (2);c - specific electric resistances of water in the riverbed (1) andsprings (2) in terms of conventional units; - d graphs of magnetometryin terms of conventional units; 3 - subaerial subsurface waterdischarge area, 4 - subaqueous subsurface water discharge area,5 - a non-freezing air hole in ice, 6 - river ice, 8 - the line offracture strike, controlling subsurface water discharge.

~ ~ It.215has moved far more f e f icient approximatedHFEP is a very informative method, providingthe EP method, when used under various permafrost- results which are relatively simple to interpret.geological conditions of the Baikal-Amur Railway The practical application of this method on thezone, and greatly surpassed it under certain con- ice bodies of Southern Yakutiya, the Amur regionditions, particularly in winter and icing opera- etc. is indicative of its possible wide use intions. Direct pef measurements provide good corre- mapping geological and permafrost boundaries underlation of acquired data with the data from conven- the snow or ice or during seasonal freezing. Thetional electrometric investigations (EP and VEP). HFEP method can also be used for tracing largeThe variation in dimensions of the feeding and water discharge channels by naled thickness andmeasuring dipoles and the spacing between them for estimating the thickness of naled bodiesallows alteration of the test depth. A disadvan- (Figure la), particularly as a form of geometricaltage of the method is the dependence of Def on the sounding. More precise estimation of ice bodycloseness of the capacitive antenna to the ground thicknesses: and the structure of the underlyingsurface which is difficult to achieve during summer frozen rocks is done by longitudinal seismic prooperationsin well-developed brush, hurmnocky topo- filing using modern portable seismic stations.graphy, shallow hummocky-sedge bogs, Nevertheless, Geophysical methods, mainly electrometry, arethe HFEP method can be considered as promising for especially important in discovering and outliningsuch investigations, similarly to CEP (continuous the disintegration zones of cryogenic rock whichelectroprofiling), which has been elaborated on are attracted usually to the upper or lower PFRrecently in PNIIIS.boundaries (Afanasenko et al. 1980). Cliff massifsGeophysical methods, their sequence and rela- of these rocks, subjected to perennial freezing,tionship to various field operations, vary accord- gave rise to high pressure in the saturating subingto specific research objectives, the complexity surface waters, and their pressure discharge isof the permafrost and hydrogeological condirions in accompanied by icing.areas of naled formation and subsurface water dis- In the northern setting o€ the Verkhne-Zeiskayacharge, time and conditions of the operations being depression the regional weathering crusts of disconducted.continuous freezing often constitute a unique capIn studies carried out in the areas of subsur- on the subsurface waters of the Unakhinsky hydrofacewater discharge during sumer, the the geo- geological massif (Alekseyeva 19781, which isphysical methods used include, as a rule, direct characterized by considerable accumulation of icecurrent, electroprofiling, resistivimetry, VEP and body fields. The builders encountered difficultiesmagnetometry. Several specific techniques, includ- in laying track for the Baikal-Amur Railway in suching longitudinal profiling along riverbeds and areas. Many road excavations made in these rocksstream-channels with simultaneous resistivimetric in winter constitute foci of intensive ice crustand thermometric observations, provide accurate formation.solutions to a number of problems, includingThe survey of subsurface water discharge areasdetection of the areas of subaqueous discharge of and particularly of those with icing was followedsubsurface water, identification of different water by specific hydrosampling for tritium, that allowedmanifestations, etc. Additional information about evaluation of the water exchange in differentfeeding, transit and discharge of subsurface water hydrogeological structures and of the chargingcan be obtained from electroprofiling, using the level (Afanasenko 1981).natural electrical field technique.The experience gained by using geophysicalAlternating current (DEMP, NFEP, CEP) electro- methods in permafrost-hydrogeological investigationsprofiling methods, which are more productive and in areas in which icing subsurface water dischargeefficient as compared to EP, are often used as aux- occurs indicates, on the whole, their high effeciliarymethods during summer regional studies. tiveness in providing reliable information; this isThe vertical structure of taliks and frozen contingent upon the use of a comprehensive approachrocks in the summer is basically estimated from VEP,WP IP data. In cases of distinct horizontalheterogeneity of the section and steeply dippingboundary surfaces between the frozen and thawedrocks, which is typical €or areas of icing and subsurfacewater discharge, special techniques areneeded for VEP operations and the interpretationof the results obtained (Dostovalov et al. 1979).During research on subsurface water dischargeareas in the winter or early spring, the operationalconditions change substantially, well as asthe structure and parameters of the test sectionsand the problems being solved by geophysicalmethods. The limited application of electrometry,particularly EP and VEP, stems from the difficultyof achieving galvanic contact with ice or frozenrock and substantial measurement errors winter;in the spring, when contact is realizable, thescreening effect of the ice body and seasonalfrozenrocks interferes. All of this stipulates aneed for a wider use of noncontact electroprospectingmethods.in solving multi-faceted problems and strictfollow-up of the acquired results at all stages ofthe operations.REFERENCESAfanasenko, V, E., and Boikov, S. A,, 1974, Characteristicsof chemical composition development andspecific electric resistances of subsurface andsurface waters of the northern part of Chulmanskoyeplateau, + Merzlotniye issledovaniya,no. 14, Publ. Moscow State University, p. 122-131.Afanasenko, V. E., Boikov, S. A., and Bomanovsky,V. E., 1980, New data on the frozen groundhydrogeologicalstructure of Dzhagdy-Sokhtakhanblock, & Geokriologicheskiye usloviya zonyBaikalo-Amurskoi magistrali: Yakutsk, p. 141-150.Afanasenko, V. E., 1981, Alteration of tritiumconcentration in subsurface water as an indicator

216of water exchange conditions in various hydro- sublake taliks in the Extreme North for thegeological structures of Baikal Amur Railwaysolution of engineering and geological problems,development zone, Thesis of the paper at All- Papers of the I11 International Conference onUnion symposium, Isotopes in hydrosphere: Geocryology: Novosibirsk, Nauka, p. 247-257.MOSCOW, p. 56-57.Timofeyev, V. M., 1977, A new method of acceleratedAlekseyeva, Z. I., 1979, Weathering crust manifes- elec troprofiling for engineering and geocryotationsin the eastern area of Baikal Amur Rail- logical survey, Papers of a scientific seminar:way (Dzheltulaksky region), & Kory vyvetrivan- Methods of engineering and geological investiiya,no. 16: Moscow, Nauka, p. 206-212. gations and mapping of the permafrost region,Dostovalov, B. N., Boikov, S. A., and Pugach, V.B., no. 2: Yakutsk, p 19-20.1979, Electrometric studies of subchannel and

PRINCIPLES OF TERRAIN CLASSIFICATIONFOR PIPELINE CONSTRUCTIONL. M. Demidjuk, G. S. Gorskaya, and V. V. SpiridonovThe All-Union Research Institute for TransmissionPipeline Construction (VNIIST), Moscow, USSRAs a basis for designing, constructing, and operating a safe of system long-distancepipelines it is essential to compile baseline assessment maps depicting engineeringconstructionconditions. These must take into account, on the one hand, the completecomplex of environmental factors pertinent to the project and, on the other, technologicaland engineering peculiarities. Construction regionalization involves terrainclassification on the basis of the most important environmental factors based on aclassification in terms of construction and engineering geology developed by theauthors.The main characteristics of modern pipelineconstruction are as follows: the enormous lengthof pipelines (4,000 km and greater), the installationof several pipelines in one corridor, thepassage through vast territories having varyingcomplex natural conditions, and finally the hightechnical parameters of the pipelines themselves,that is, large diameters (1220-1420 mm) and highpressure (7.5-10 MPa), which define the categoryand responsibility of the installation.All these determine the basis for engineering,constructing, and operating long-distance pipelines.The methodological basis for engineering andgeological investigations, especially in permafrostfication of construction elements.regions, should be terrain classification based on The engineering-geological aspect of the classicomprehensiveenvironmental factors which affect fication includes the scale of the main environboththe construction process and selection of a mental factors (surface and frozen ground) whichmode of construction which takes into consideration define the construction process and the environfuturepipeline design-environmental interaction. mental impact of pipelines. In addition theSuch classification involves dividing the terri- classification includes permafrost and anthropotoryinto spacial regions and results in a map or genic processes and phenomena.a series of maps of engineering and constructionThe surface factors pertaining to pipeline conregionalization.struction are as follows:These maps should include the entire complex of - character and types of vegetation, whichenvironmental factors specific to the given constructionmode as well as its design, technicalfeatures, etc.As a theoretical basis for the classificationby compressive engineering and geological analysisthe relationship "geological environment-engineeringproject," we suggest a systematic approach tothe principles of regionalization.A systematic approach suggests the developmentof an industrial classification of environmentalconditions with regard to predictions of changeas well as technical standards for the given typesof installation that contain technological require-ment~, available design solutions and the productiontechnology rates. The choice of the territoryestimating elements deals with its regionalpeculiarities and specific features of its development.In view of the above stated problems, VNIISTconcludes the work on USSR the terrain classificationwith regard to pipeline construction tasks.The authors have developed and incorporated intothe design a construction and geological classificationsystem that also constitutes a classificationof engineering and geological conditionsaccording to the complexity of the constructionproject and a standardized classification of pipe-line construction modes and schedules. On the basisof this classification system, we have developedsketch maps of engineering and constructionregionalization that include climatic, engineeringgeological,and social-economic regionalization.This system of construction, engineering, andgeological classification consists of two parrs:engineering-geological classification and classi-influence movement of machines and equipment, inaddition to determining the heat-moisture exchangein Soils, their thermal state, the extent ofseasonal freezing and thawing;- hydrological factors: watercourses (rivers,channels, springs), water basins (lakes, waterstorage basins), swamps. Size and depth of waterbasins and swamps, the content and thermal conditionsof sedimentary peat affecting constructiondecisions, methods of laying pipe, feasibility ofmoving equipment and the complications in the pipelineconstruction process;- relief morphometrical Characteristics (horizontaland vertical disintegration, surface inclination)affecting construction decisions, pipelineconstruction mode technology and equipment, aswell as types and magnitude of engineering andgeoLogical processes.The surface factors of natural environments alsocomprise special climatic features with zonaldistribution. Air temperature, atmospheric precipitation,snow distribution and thawing, wind217

!18regime-all these factors define the constructionwork schedules and season. In addition, climaticconditions are taken into account in calculatingthe pipe and soil temperature behavior and thestability of the above-ground pipelines under windloading. The frozen ground factors governing thethermal and mechanical interaction of pipelineswith the ground in permafrost territories are asfollows :- type of permafrost region: continuous anddiscontinuous permafrost, massif island permafrostand permafrost islands, persistent snowbank andice-lenses, relic permafrost;- mean annual ground temperature at a depth ofits annual fluctuation;depending on slope steepness); landslides, rock- composition, cryogenic structure and physical streams (by intensity of development depending onand mechanical properties of frozen and thawing slope steepness); seismicity (by magnitude).ground (lithological features, moisture, iceAnthropogenic factors include: railways, highcontent,heaving properties, thaw settling, sal- ways, farming lands, populated areas, reservations,inity and corrosive activity of ground);animal migration routes, etc.- thickness, structure and properties of ground in Classification of structural elements includesseasonally thawed and seasonally frozen layers; factors, defining types of pipeline laying, pipe-- permafrost and physical-geological processes line design, construction technology, and operation.and phenomena (thermokarst, thermal erosion, frost Depending on where the sections are locatedfracturing, heaving, icing, solifluction, ground relative to ground surface they are differentiatedices, surface waterlogging, new formation of frozen as follows:ground, seismicity, and gravitation processes,etc,).Design and construction of long-distance pipelinesrequire detailed prediction of changes ofall engineering-geological factors, because whennatural environmental conditions are disturbed,changes in the permafrost temperature regime occur.As a result, the composition and properties of thepermafrost are altered and the intensity of engineering-geologicaland permafrost processes increases.The above-mentioned factors are assessed fromthe standpoint of pipeline installation with regardto difficulties of construction and reclamationactivities, as well as ground characteristicsaffecting the pipelines (ground content, groundthermal state, flooding, soil subsidence, developmentand intensity of permafrost processes andphenomena).A detailed engineering and geological classifi-annu .a1 soil temperature); ice content of frozengrounds (by relative thaw subsidence); frost groundheaving (by relative heaving); soil salinity (bytotal content of easily dissolved salts % in drysoils; soil corrosion activity (by specific electricalresistance of soils); soil flooding (by thedepth of the first water-bearing horizon).Permafrost processes and phenomena include:frost fracturing and underground ice (by intensityof area development); icing (by presence andpossible development of icing of different originsriveror ground); solifluction (by intensity ofdevelopment depending on the steepness of slopes);sereis crumblings (by intensity of development- underground, when the upper centerline of thepipeline is below the ground surface;- on-ground, when the lower centerline of thepipeline lays on consolidated natural or artificialfoundation, and the upper above the ground surface(either a berm or out in the open).- above-ground-when the pipeline is laid uponseparate piles or pile trestles at a height 250 ofmm above the ground surface.Depending on the operating temperatures thatcharacterize the pipe-environment interaction(ground, water, air), the pipeline sections aredifferentiated as follows (Table 2):- negative-with constant operating temperaturebelow zero;- cold-with a plus or minus temperature, butwith a mean annual temperature equal to or lowerthan -1°C;- warm-with a plus or minus temperature, burwith a mean annual temperature higher -1°C; thancation is presented in Table 1. This classifica- - positive-with a temperature higher than zero.tion may be used at the working drawing stage and,given the necessary data, at the technical project TABLE 1 Pipeline classificationsstage. For small-scale investigations it may beexpanded according to the initial data.This classification assesses engineering andTemperature Construction seasongeological conditions according to five categoriesregime(or degrees) of complexity. The following surfaceYear round Summer Winterconditions axe included:- vegetation, availability of forests, vegeta- Negative N NAY NS NWtion composition, thickness and height of tree Cold C CAY cs cwtrunks, cover, crown density;Warm W WAY ws ww- lakes and swamp cover (type of peat deposits, Positive P PAY PS PWterrain passability, extent (X) and depth oflakes) ;- watercourses (their nature, width of high and Possible technical decisions for every engineerlowwaters) ;ing-geological type of pipeline section (Table 1)- relief (morphometric properties-surfaceare selected on the basis of technical requirementsinclination, vertical and horizontal disintegration, and construction conditions (Table 2). On theslope length).Frozen ground conditions are classified accordbasisof technical decisions and standards, tentariveeconomic indices can be derived as criteriaing to the following factors: soil thermal conditionby thawing-frozen soil ratio and meanfor comparison of various routes,By using letter designations €or various classi-

219TABLE 2 Classification by construction, engineering, and geological factorsEngineeringand geologicalfactorsClassification of engineering and geological conditionsComplexity categoryI I1 I11 IV V1 2 3 4 5 6VegetationArea withoutvegetation(beaches, lowlyingfloodplains, driftingsand) orgrass-covered(CC 20"ation a< 2", L > 300 m L > 300 rn 7' < a 20' L > 300 mlength (L)L > 300 m> 300 mR1 R2 R3 R4 R5-"""""""""""""""""""""""""---GroundcontentRack Rock debris Sand, sandy Sandy loam, PeatsoilsclayGZ G3 G4 Gs

~~220TABLE 2(contlnued)1 2 3 4 5 6GroundthermalstateUnfrozen Thawing ground Thawing ground Continuous Continuous frozen(Thawing) with 20% dis- with more than frozen ground groundground continuous 20% permafrost -1" > T > -3' T < -3'T>O permafrost0 > T ? -1'"is lands"0 > T > -loM1 M2 M3 M4 MsIce content Poor ice Low ice Moderate ice Ice-rich Extremely ice-(relative content content content 0.3

22 1TABLE 2(continued)1 2 3 4 5 6Soil corrosion Slight Low Moderate High EXK remeactivity C, 100 cm 100 > C > 50 50 > C > 20 20>C> 10 cc 10(in cm)c2Soil flooding Slight LOW Moderate Heavy Ext reme ly heavyin m; minus D > -2.5 -2.5>~>-1.2 -1.2>D>-0.7 -0.7>D>+0.5 D < "0.5(-) indicatesbelow ground;plus (+) aboveground surface01 02Slope processes None Solifluction Slides, rock Screes, aval- Earth flows,(at slope streams (at anches (at avalanches (atsteepness slope steep- slope Steep- slope steepness2-7") ness 7-12'] ness 12-18'] > 18")L1 Lz L3 L4 L5""""~"""~"""""""""-"""-----"------Seismicity No seismic Earthquake Earthquake Earthquake Earthquake forcactivity force 6 and force 6-7 force 7-8 >alesss1 s2 53 54 85...........................AnthropogenicfactorsNoneRailroads, Farm land Infrequently Populated areas,highways used terri- resertories migration routes,etc.fication factors and structural elements, conditionsof varying complexity for the varioustypes of engineering and geological regions (orprovinces, districts and regions depending on thedegree of detail and the stage of design) areencoded.The construction, engineering and geologicalclassification, developed by VNIIST on the basisof the environmental factor analysis mentionedabove and pipeline construction practice, may beused as a guideline for the organization of perma- Beliy, L. D., 1964, Theoretical principles offrost geological studies on pipeline construction, engineering and geological regionalization:scientific analysis and systematization of pre-Moscow, Nauka.liminary permafrost data; it was also designed to Demidjuk, L. M., Gorskaya, G. S., and Spiridonov,assist in making well-grounded decisionstheV. V., 1982, The classification of territoriesconstruction and technological scheme of productbased on construction conditions: A basis fortransport with regard to possible environmental rational use of geology in pipeline construction,changes during construction and operation of anPapers of the Interagency Conference: Geocryoinstallation.In addition, the classification and logical prediction in developing regions of theengineering assessment and construction maps have Far North: Moscow, p. 66-67.been used by design organizations to select optimum Spiridonov, V. V., Demidjuk, L. M., and Gorskaya,routes for oil and gas pipelines, to make precau- G. S., 1981, The principles of civil engineeringtions, to mitigate the environmental impact, toregionalization in linear construction: Theassist reclamation within the right of way, andconference theses, Geocryological problems into provide reasonable estimation of the construc- the Transbaikal, Chita, p. 136-138.tion rem.Sulakshina, G. A,, 1979, Engineering and geologicalUsing the classification system for preliminaryinvestigations permits standardization of the map-ping procedure for engineering and geologicalregionalization, that up to now has depended on thequalifications and creativity of the compiler.Engineering and construction classification ofterritory on the basis of construction, engineeringand geological factors has already been usedto design a number of large-diameter oil- and gaspipelineprojects.REFERENCESclassification of sites as a basis for predictingman induced geological change: EngineeringGeology, v. 3, Moscow, p. 49-54.

ON THE PHYSICOCREMICAL PROPERTIES OF THESURFACE OF DISPERSED ICE (SNOW)N. F. Fedoseev, V. I. Fedoseeva, E. A. NechaevPermafrost Institute, Siberian BranchAcademy of Sciences, Yakutsk, USSRThe interaction between a dispersed ice (snow) surface and toluene and hexanol solutionsin a large number of organic compounds was studied. It was found that the ice surfaceadsorbed only substances with an ionization potential 9,6 of eV. Formation of aliquid-like layer on the ice surface occurred in 48, 15 and 2.5 hours at temperaturesof -10, -5, and -2°C respectively. The solubility of carbon acids in the liquid-likelayer was shown to be lower in than the water.All large-scale processes occurring in nature tion (Figure 1) using a transformed Langmuir equaandassociated with the existence of water in a tion it becomes possible to determine the specificsolid dispersed state are in some way or othercon- surface of samples of non-metamorphized (S SP -nected with small-scale processes occurring on the 110 m2 /kg) and metamorphized (Ssp = 25 m2 /kg) snow.surface of dispersed ice, whether it is substance In addition to the aforementloned substances,migration over chin films in permafrost or sublima- those highly soluble in water and having a hightion phenomena during the metamorphosis of snow, etc. water-toluene distribution factor (inferior alco-Therefore, the study of physico-chemical properties hols and acids) are markedly absorbed by snow,of a dispersed ice surface is of interest to a exposed at the temperature of -10,-5, -2°C. Thelarge group of specialists. Until now, strongevidence has been acquired (Kvlividze et al. 1974,1978) for the existence on the dispersed ice surfaceof a so-called liquid-like film, representingan intermediate structure between ice and water.The properties of this film have been the subjectof a considerable number of papers (KvZividzeet al. 1974, 1978). There are, however, practicallyno data on the interaction of the ice surface withsubstances introduced into the system. We havenature of the interaction, however, is quite different;the sorption ability is independent of theionization potential and the amount of sorptionincreases linearly with increasing solution strength*The above-mentioned facts can be explained byassuming that the sorption of substances highlysoluble in water is due to the transition of theirmolecules from the layer of the organic solvent tothe liquid-like film.We studied the absorption by snow of formic (I),studied the interaction of dispersed ice (snow)with toluene and hexane solutions of many organiccompounds. Samples of fresh snow were taken on theleeward side far outside the limits of a town. Thesnow cover held for a Considerable and time all theexperiments were conducted at a temperature of -hacunder conditions when a liquid-like film is presenton the surface of dispersed ice.It turned out that of the numerous (more than50) organic compounds sampled, representing differentclasses of molecules, only 1,2-naphthahynoneand 0-brombenzoic acid are absorbed by the icesurface. It should be noticed that the ionizationpotential of these compounds is 9.6 eV,In this respect, adsorption regularities on icedo not differ from those on oxides. As has beenshown in Nechaev et aL. (1978, 1979). out of aqueoussolutions on the oxide surface, organic substancesare adsorbed which have a strictly defined ionizationpotential, referred to as the oxide resonancepotential (Ires.). When the ionization potentialof a substance deviates from the Ires value by morethan 0.1-0.2 eV, adsorption is not detectable.On the basis of the data obtained it seemspossible to conclude that for ice Ires = 9.6 eV.This inference is also supported by the fact thaton the ice surface anions having an ionizationpotential in between 9 and 10 eV are specificallyadsorbed.By processing data on 0-brombenzoic acid adsorp-222chloracetic (11) and acetic (111) acids fromsolutions in toluene (1,II) and hexane (111). Theconcentration variation of substance after introducinga weighed snow sample was determined by theneutralization method. At high concentrations meltingof the snow sample occurred to produce a bulkphase of aqueous solution.0 f “ O000 0I0 I 2 3 IO+.C,~FIGURE 1 Isotherms of 0-brombenzoic acid adsorptionfrom a solution in hexane on snow samples,taken from a water reservoir surface (1) and anarea at some distance from (2). it

22 3According to current understanding, two liquid absorbed substance, to a first approximation, waslayers may be present on the surface of ice crystals linearly dependent on concentration.introduced into a non-aqueous acid solution. On the Experimental data have demonstrated that a atone hand, as ice comes in contact with an acid decreasing temperature, more time is required forsolution, it may melt to produce a layer of acidaqueous solution of volume V, in which the acidsnow sorption properties to change. It has beenestablished that this necessitates an exposure ofconcentration will be determined by temperature and samples in a moisture-saturated air atmosphere forcan be inferred from a phase diagram, On the other 48, 14, and 2.5 hours at -10, -5, and -2'C, respechand,it can be assumed that of part the molecules tively. At -2O"C, a change in sorption propertieswill pass into a liquid-like layer, thus producing occurred only after a three-week exposure.a solution whose properties may differ from the These facts can be explained, if one acceptsbulk phase. This is evidently due to the fact that that considerable time, dependent on temperature,the water structure within this layer a is transi- is required for a liquid-like layer to develop ontion stage between the water structure in the bulk the ice surface.and the ice structure. We will denote the volume According to the available data (Nechaev et al.of this layer by Vx.1978, 1979) on adsorption of organic compounds fromThe bulk phase V can exist if its acid concentrationis at equilibrium with ice and toluene.The equilibrium Concentration with respect to iceaqueous solutions on oxides, one may assume thatthe appearance of a liquid-like layer, and thereforeof a layer of water molecules adsorbed on the(Ck) is derived from the phase diagram, while with ice surface, causes the acid molecules to be disrespectto toluene (C:) it is determined by the placed from the surface. This is due to the factwater-toluene (KO) distribution factor.Let us assume that the initial acid concentrationin toluene is so small that a concentration atequilibrium with ice, i.e. CL < Ci, cannot arise inan aqueous solution. In this case the bulk phasedoes not occur. If, however, Ck > Cia then icethat the H,O molecules produce a hydrogen bond withthe surface atoms; on the ice surface only thosesubstances capable of producing a bond srrongerthan a hydrogen bond can be adsorbed. As has beenshown (Nechaev et al. 1978, 1979), such conditionsapply to the adsorption of substances having andissolution will continue until it reaches equil- ionization potential that corresponds to a resonibriumconcentrations with respect to ice and ance potential of a solid surface.toluene C C ~ = c:).Therefore, it can be concluded that isothermsTo find the concentration of toluene solution 1,l' in Figures 2-4 characterize adsorption of acid(Csc) below which the bulk phase does not arise, molecules from a toluene solution on the ice suri.e.CL Ci! we determined the distribution fac- face, while isotherms l", 1"' , and 2" characterizetors of formlc and chloracetic acids between water the acid molecule distribution between the tolueneand toluene at temperatures over O°C and extrapol- volume and liquid-like film. In this case at smallated to a low-temperature region. The respective concentrations the amount of absorbed substancevalues of the distribution factors K, and Csc are must be a linear function of equilibrium concenlistedin Table 1. Apparently, a study of thetration in toluene which is observed experimentally.properties of the liquid-like film would be worthwhileat concentrations smaller than Csc.TABLE 1Pt,'C Ck,M KO 1OSCsc,M Ci,M KO 1O2CSc,Mformic acid (I)chloracetic acid (IT)-2 0.87 688 1.26 0.77 54.5 1,41-5 2.50 734 3.41 2.50 56.2 4.45-10 4.90 830 5.90 5.53 59.4 9.31The investigations indicate that the sorptionproperties of snow, stored at -35 to -5O'C. dependon its exposure time at a given temperature.Measurements taken as soon as the snow attained atemperature equilibrium with ambient air providedisotherms, which exhibited a well defined inflection,the so-called point B (Greg and Singh 1970),and which permitted determination of the specificsurface of dispersal ice on the assumption that themolecules form a dense adsorption monolayer. Inthe case of measurements carried out on snow thathad been exposed for a definite time at a giventemperature in a moisture-saturated air atmosphere,the sorption isotherm changed shape. The amount ofFigure 2 Isotherms of sorption I1 (1,l") andI (2") on snow at -2OC without preliminaryexposure (1) and with a 2.5-hour exposure(l", 2'1) .

224010 /"0 I"Figure 3 Isotherms of sorption 11 (l,l", 1"')and I (2") on snow at -5OC without preliminaryexposure (1) and with 15-(1", 2") and 25-hour(1"' ) exposures.Figure 4 Isotherms of sorption I1 (1,l"' ) andI (2") on snow at -lO°C without preliminaryexposure (1) and with 25-(1'), 48-(1") and 120-hour (1"' , 2") exposures.Deviations from the linear dependence are observedat concentrations C 2 Csc, which indicates theaccuracy of the distribution factor, Y-, valuesextrapolated to subzero temperatures.Figures 2-4 (curve 1) and Figure 5 show Khatthe amount of adsorbed molecules of formic, chloraceticand acetic acids at monolayer filling is thesame (0.4 lO-*mole/kg) and is independent of temperature.These facts make it possible to concludethat the same orientation on the surface ofmolecules of these acids is obtained, with thecarboxylic group towards the surface. Assuming thearea occupied by one molecule to be 0.205 nm2 (Adam1947), we have obtained a specific surface S =SP490 m*/kg.This quantity exceeds the values, inferred from'adsorption of 0-brombenzoic acid (S, = 110 m*/kg).This is presumably due to the fact tlat snow conrainsnarrow pores, accessible to small moleculesof inferior acids and inaccessible to the largemolecules of 0-brombenzoic acid.The specific surface value of 490 mZ/kg can beused to estimate the thickness of the film. Assumingthat the water-toluene distribution factor andthe liquid-like film-toluene factor are the same,it is possible to calculate a specific volume ofthe film, V, = G/Ko Ck. By dividing the value ofV, by Ssp we can derive the thicknesses d, listedin Table 2. The differences in thickness valuesTABLE 2t,OC d,m Kf d,nm Kf df,nm*formic acid (1) chloracetic acid (11)-2 8.3 519 5.1 25.0 11,O-5 3.8 557 2.4 27.0 5.0-10 2.0 - 1.2 -*Kvlividze et aL. (1974)of the liquid-like film, inferred from sorption Iand I1 with the use of the distribution factor forthe water-roluene, suggest that the properties ofbulk water and water within the film are differing.On the basis of the data acquired we can concludethat the solubiliry of formic and chloraceticacids differs in the liquid-like film and bulk phaseof water, We have calculated the film thicknessesat-? and -5°C using data reported by Kvlividze etal. (1974) from the amount of the movab1.e phase atthese temperatures for snow with a specific areaof 1000 m2/kg. (the value of df in Table 2). Thesewere used to tal-culate the pertinent distributionfactors Kf = G/df Ssp CE, also listed in Table 2.

225In conclusion, it should be noted that theseresults must be taken into account when conductingvarious tests of permafrost, snow and compact iceat temperatures close to that of ice melting,especially for samples subjected to preliminarydeep cooling. If delayed formation of a liquidlikefilm is not taken into consideration, then onemay obtain values which are far from equilibrium.The study of the dissolving power of the filmwill be extended to other organic compounds, inparticular, to inferior alcohols, after relevanttechniques have been developed. Research ispresently under way on the film's dissolving powerwith respect to inorganic compounds.REFERENCESP/ I I I I0' 1 2 3 102C,mFigure 5 Isotherms of sorption I at -15OC (I),-2O'C (2) and I11 at -25OC (3) without preliminaryexposure of snow.The comparison between the extrapolated and calculatedvalues of the distribution factor KO and Kindicates that the acid solubility in the liquidlikefilm is lower than in water. There is a considerabledecrease in solubility of chloracetic acid,for which the distribution factor is an order ofmagnitude lower.Adam, N. K., 1947, Physics and chemistry of surface:Iloscow-Leningrad, Gostekhizdat.Greg, S. and K. Singh, 1970, Adsorption, specificsurface porosity: Moscow, Mir.Kvlividze, V. I., V. F. Kiselev, A. V. Krasnushkinet al., 1978, Proceedings of the Third InternationalConference on Permafrost, Edmonton,Alberta, Canada, v. 1, p. 113.Kvlividze, V. I. , V. F. Kiselev, A. B. Kurzaevand Z. A. Ushakova, 1974, The mobile water phaseon ice surfaces, Surface Science, v. 44, No. 1,p. 60.Nechaev, E. A. and N. F. Fedoseev, 1978, Adsorptionof the organic matters from water solutions onthe oxides of 4-valent metals. Zhurnal phisicheskojkhimii, v. 52, No. 5, pp, 1250-1254,Nechaev, E* A. and V. P. Romanov, 1981, Adsorptionof anions on ice and freezing potentials, Zhurnalphisicheskij khimii, v. 55, No. 7, p 1818-1821.Nechaev, E, A,, R. Ja. Shaidullin and V. A. Volgina,1979, Adsorption of the organic matters fromwater solutions on the oxides and hydrooxides of2-valent metals. In Sorption and chromatography:Moscow, Nauka, p 75-78.

THE THERMAL REGIME OF PERMAFROSTSOILS IN THE USSR11. K. GavrilovaPermafrost Institute, Siberian BranchAcademy of Sciences, Yakutsk, USSRThe author has compiled maps of heat flux through the ground surface and its relationshipto the radiation balance during the thaw season. The correlation between theradiation balance and the heat flux is slightly higher in permafrost areas. Thus,in the arctic regions the ratio 20% is but in areas of seasonal freezing of the groundit is less than LOX. A ratio of 12.5% corresponds approximately to the southern limitof the continuous permafrost, a ratio 10% of to that of the discontinuous zone andone of 7.5% to that of sporadic permafrost. The total heat flux through the groundsurface is greatest in the continental northeastern region USSR of the reaching 200MJ/mZ. Northwards, westwards, and southwards it decreases to 100 M3/m2. This doesnot mean, however, that the greater heat flux results in a greater depth of thaw.Here a considerable amount of heat is being expended on warming the ground fromextremely low winter temperatures up 0" to and on the ice-water phase change.Ground soil thermal flux is one of the major thermal flow meters under conditions existing incomponents of the thermal balance of the earth's areas near Moscow and Vorkuta (Golubev and Pavlovsurface and represents the upper boundary condition 1961). Pavlov and Golubev have also proved theof the thermal status of rocks. It serves as a desirability of using LTIKE' thermal flow meterslink between climate and perennial freezing of the in permafrost.upper lithospheric layers. However, experimentalWe have already completed a temporal andinvestigations on thermal flux in ground soils are geographical generalized description of thisscarce. The existing methods for computing these important index of the thermal regime of theflows (Manual etc. 1977, Averkiev 1960, and others) climate (Gavrilova 1981).do not always yield reliable results for permafrost In the annual derivation, the radiation balanceand deep seasonal freezing of rocks. This is(R) in the permafrost region is the main source ofassociated with the difficulty of estimating the heat to the earth's surface (500-1500 MJ/m2). Thisheat of water ice phase transitions as well with as heat is used up mainlyevaporation and warmingthe complexity of an accurate determination of the atmosphere. In regions with a higher moistureinitial parameters involved in calculation formu- content, a greater amount of heat is used by uplas.evaporation. Therefore, in the country's EuropeanDirect observations of thermal flux in ground territory (ETC) evaporation consumes nearly three-soils in the huge territory of the USSR are chieflyconducted only by permafrost researchers working atthe former V. A. Obrucbev Permafrost Institute, theUSSR Academy of Sciences (Golubev, Pavlov) and theInstitute of Permafrost, Siberian Branch, USSRAcademy of Sciences (Balobaev, Gavrilova, Gavrilyev,Molochushkin, Pavlov, Olovin, Skryabin, Tishin, andothers). Thermal flux measurements in ground arecarried out at the Institute of Permafrost, Siber-ian Branch of the USSR Academy of Sciences, bymeans of homemade heat flow meters, usually ofacrylic plastic (Ivanov 1961, Pavlov and Olovin1974) or by small-thermal flow meters designed atthe Leningrad Technological Institute for RefrigerationIndustry (LTIKP). The thermal-balanceresearch group, headed by this author, utilizes thelatter in their research. According to our findings(as compared to calculated values for adetailed determination of humidity, temperature,and thermal-physical properties), the LTIKP rubberthermal flow meters (30 cm in diameter and about 1cm thick) do produce errors for individual times,but are quite acceptable as far as the 24-hourtotals are concerned (reciprocal compensation ofdisplaced maxima and minima). This was also confirmedby comparative measurements with thesequarters of the radiation balance heat; in theArctic part, about two-thirds; in droughty CentralYakutia, about half; and in dry areas of Mongolia,less than one-quarter. The ratios of heat expeadi-'cure on turbulent heat exchange with the atmosphereare reverse: the greatest loss occurs in the dryareas of Mongolia (in excess of three-quarters ofthe radiation balance); for Central Yakutia it isslightly less than half; in the Arctic, about onethird;in ETC, less than one-quarter (Pavlov 1979,Molochushkin 1969, Gavrilova 1973, 1974, andothers).Part of the radiation balance's annual heat isused to thaw snow, the greatest amount beingexpended in the Arctic regions of the country(about 10%). Although the snow there is not thedeepest occurring in Euroasia (40-50 cm), by theend of the winter it is very dense (0.30-0.35g/cm3); on the other hand, the yearly radiationbalance totals for the Arctic are the smallest(within 500-600 MJ/m2). In the northern parr ofETC and West Siberia, snow thawing consumes about7% of the radiation balance heat (by the of endwinter the snow depth is 60-80 cm), in WesternETC, about 5% (50-60 cm), and in continentalCentral Yakutia with a comparatively shallow226

2 27snow cover (40 cm by the end of winter), about 2%.In semi-arid regions of Southern Mongolia, wherethe snow cover lies between 1 and 4 cm, the heatexpended on snow thawing with respect to the yearlytotal of radiation balance (more than 1700 MJ/cm2)is negligible.The ground thermal flux total through the earth'ssurface (B) during the year is, for the most part,close to 0. For individual years it can be within20-60 MJ/mZ, which comprises 0 to f5% of the radiationbalance's yearly value.Other correlations between the thermal balancecomponents of the earth's surface occur during warmand cold seasons. From the standpoint of geocryology,the total accumulation and release of heatdurlng the freezing and thawing seasons are ofgreatest interest (the criteria of the seasons arethe dates of stable transition of temperature onthe earth's surface through O'C). Naturally,seasonal ground freezing increases in duration whenmoving from south to north and from west to east,while seasonal thawing, on the contrary, decreases.Thus, within the USSR's Asian territory, the durationof the freezing season is as follows: Arcticcoast-250 days, the north of Western and EasternSiberia-230 days, Central Siberia and CentralYakutia-200-215, the near-Baikal area-185 days,etc.The season of surface ground soil freezing coversnot only the wintertime, but also part of autumnand a substantial portion of spring. During theautumn and spring, a large re-organization occursin the thermal regime of the atmosphere, theearth's surface and in the upper layer of rock.Aconsiderable expenditure of the thermal balanceduring spring freezing is due to heat consumptionby snow thaw. In western ETC it consumes more thanone-quarter of the heat, in the Arctic, about onefifth,and in Central Yakutia, about one-sixth.Only in Southern Mongolia, where the snow cover isshallow and disappears early, this fraction is amere 3%. In the spring there is also an increasein the heat used up by evaporation. This consumption,for the freezing season together with autumnevaporation is, in Western ETC between 35 and 40%,and in Siberia from 20 to 30%. The lowest valuesapply for the Arctic and dry areas in Mongolia (5-10%) *Despite increased solar radiation in the spring,the total radiation balance for the freezing seasonis mostly negative or close to zero (it is positiveonly at some locations). Thermal flux for radiationfrom the surface is: in Western ETC about 402,in Northwestern Siberia and in Central Yakutia 60-70%, and on the Arctic coast 75%.The thermal loss by the earth's surface due tosnow thaw, evaporation, and radiation is cornpensatedfor by the heat input from the atmosphere:65-70% in Western ETC, 45-50% in the Arctic, and20-35% in Central Yakutia.Ground thermal flux provides a substantialreplenishment of the earth's surface heat over thefreezing season. In this case it makes the largestcontribution in regions of perennial and deepseasonal freezing. Thus, in Western ETC (not deepfreezing) the ground thermal flux constitutes30-35%, in Northwestern Siberia 40-452, in Yakutia55-752, and in Southern Mongolia (deep freezing)75-802.Characteristically, ground thermal flux throughthe earth's surface changes its sign in autumnwhile still at positive values for the radiationbalance and long before the beginning of freezing.This suggests that a specific amount of heat andtime are required for the thermal field to reverse.Thus, the heat flow into soil traverses zero beforethe beginning of freezing: in Western ETC and inSouthern Mongolia 2 months, in the south of CentralSiberia, one month, in Central Yakutia 2 weeks, andin the Arctic one week before. In the spring theground soil thermal flux reverses its sign, butmainly at positive radiation balance and with snowstill present, i.e. prior to the onset of thawing.This has the following delays: in Western ETC 10days, in the northern half of Siberia 1 mpnth, andin Southern Siberia and in Mongolia, with theirfrequent recurrent snowfalls, 1.5-2 months.The structure of the thermal balance of theearth's surface for the thaw season is welldefined. The heat used to thaw the rest of thesnow, since this season extends into part of thespring, is an additional factor. The overallradiation balance is positive and varies in theterritory under consideration from 1200 to 1400MJ/m2 in Western ETC and in Central Yakutia from750 to 800 MJ/m2 in the Arctic.In Western ETC the main thermal flux is used forevaporation (two-thirds to three-quarters of thetotal radiation balance) and then for warming theatmosphere (about one-quarter to one-third). Fourpercent of the heat is used to warm the soil andabout 1-2% to thaw snow. In Northern ETC, inWestern Siberia, and in Central Yakutia the ratiosof thermal flux used for evaporation andturbulent heat exchange with the atmosphere areapproximately equal (40-45%). Heat flow usedto warm the soil comprises 10-12X, while thatused to thaw snow averages 1%.Analysis of the available actual data shows thatthe totals for soil heat flow for the thaw season(as well as for the freezing season) and theirrelationship to the radiation balance turn out tobe fairly stable in separate regions and vary asone moves from north to south, thereby reflectingthe properties of the permafrost regime. Thisallows for, on the one hand, representation oftheir spatial distribution (which we actually didfor the thaw period using the most numerous andreliable data available) and, on the other hand,indicates the possibility of subsequent permafrostclimaticzoning.For example, the distribution of the ratio ofsoil thermal flux to radiation balance of theearth's surface (Figure 1). The greatest share(over 20%) occurs in the coldest and moist (icing)regions of the Arctic islands and sea coast. Tothe south the ratios diminish, increasing only inthe mountains (up to 15%). Typically, in manyregions (except for dry Central Yakutia) the 14.5%isoline ratio passes close to the boundary ofcontinuous permafrost, the 10% isoline runs alongpermafrost islands in the west and discontinuouspermafrost in the east, and the 7.5% isoline, alongsporadic permafrost in the Far East.Since there are more observations on the radiationbalance than on thermal flow into the soil,by knowing the characteristic B/R ratios forindividual regions, one is also able to evaluate

2 28FIGURE 1 The ratio (X> of the sum of heat flow for soil to the sumof radiation balance for the thaw season. Boundaries of permafrostzones: 1, continuous; 2, discontinuous, 3, islands; 4 , sporadic.FIGURE 2 The sum of heat flow for soil (W/m2) for the thaw season. Boundariesof permafrost zones: 1, continuous; 2, discontinuous; 3, islands; 4, sporadic.the thermal flux totals for the season. Of course, most remote near-Atlantic islands of the Arctic,total ground thermal flux depends both on thewhere the thaw period is short (60-65 days). Toseason's duration and on the temperature differencesin the upper layer of soil. In addition,temperature gradients are greater in regions ofgreatest freezing. Figure 2 shows that in thethe south, as the duration of the season increases,the sum total of flow increases 105-115 to MJ/m2 innorthern ETC. But further in ETC (not shown onthis map) this flow again decreases, now but inpermafrost region the smallest amount of heat flow conjunction with a decrease in the temperatureto soil (on the order of 65 MJ/m2) occurs on the gradient, to values on the order of 40-45 MJ/m2 in

TABLE 1 Monthly Thermal Balance Constituents in the Above-Ground Cover and Within in W/mZ SoilNeryukteitsy 1965-1967229Freeze ThawLow Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec season season YearlyB -22.79 -16.09 -11.73 -7.84 36.03 58.32 38.76 16.84 3.52 -27.02 -30.88 -34.19 -150.55 153.48 2.93Bsn 0.04 0.42 0.84 0.75 -0.04 -0.04 -0.17 1.34 1.34Bgr-22.83 -16.51 -12.57 -8.59 36.03 58.32 38.76 16.84 3.52 -26.98 -30.38 -34.02 -151.89 153.48 1.59a , o 0 0 0 4.02 10.81 4.74 -6.83 -10.73 -2.01 0 0 -2.01 2.01 0Bph 0 0 0 19.15 25.47 16.80 10.35 0.55 -72.32 0 0 -72.32 72.32 0B- -22,83 -16.51 -12.57 8.59 12.86 22.04 17,22 13.32 13.70 47.35 -30.38 -34.02 -77.56 79.15 1.59Notes: B - thermal flow through Earth's surface (surface of vegetation, snow); Bsn - heat, accumulatedby snow cover; B - thermal flow through soil surface, i.e. the one directly penetrated or into escapedfrom soil; B+ - ieat, accumulated in unfrozen layer (in the positive temperature zone); layer Bph - heatof phase transitions, consumed for soil thawing or released in the freezing process; B- heat, penetratedinto underlying frozen layers (negative temperature zone). The area of Neryukteitsy is situated in theright bank of the Lena River valley. Diverse-grass, thin-leg carex steppe; sandy loam, sand. It iscomparatively moistened in the first half of the summer, the mean moisture for the season in a 0-20 cmlayer is 35%, below-23%. Maximum thawing is 180 cm. The mean height of snow varies between 5 cm inOctober and 31 cm in March.the vicinity of Leningrad and Moscow, i.e. inregions where the ground is not deeply frozen.As one moves from the European part to East theor, putting it another way, as the climate becomesincreasingly more continental, the totals forground thermal flux increase. Their greatestvalues (on the order of 165-190 MJ/mn) occur in thenorthern half of the USSR North-East, i.e. theregion having the coldest winter or the greatesttemperature differences in the soil during warmup,Since the annual total thermal flux to groundsoils through the Earth's surface can, for practicalpurposes, be assumed to zero, be the map inFigure 2 should be extended also to the freezingseason, with the opposite sign only. a As result,the largest loss of heat by ground soils (165-190W/mz) occurs in the region of continuous permafrostin North-Eastern Yakutia with its severeclimate, after which it gradually decreases towardsthe areas of deep and shallow seasonal groundfreezing. This agrees quite well with the actualsituation.The absolute values of thermal flux through thesurface determine neither the absolute temperatureindices in the upper ground layer, nor the of depthseasonal thawing. Considerable flux during thewarm period of the year in northern regions onlyindicates that more heat was expended to restruc-ture the thermal field during winter freezing. Asubstantial portion of this heat in permafrostregions is used for ice-water phase transitions,while a smaller share goes to warm up the thawedlayer. Thus, according to our investigations(Gavrilova 1966, 1967a, 1967b, and others) inCentral Yakutia with its continuous permafrostand annual temperature fluctuations, the warming-upof permafrost consumes nearly one-third of thethermal energy, while in the North-Transbaikal'sregions which only experience deep freezing, only2%. In both cases, more than half the heat isused for thawing (2 and 5 m). The remaining heatis used to change the temperature in the thawedlayer: less than 10% in Central Yakutia and over40% in North Transbaikal.A general picture of the structure of thermalbalance of soil in the region of permafrost anddeep seasonal freezing of soil been has presented.However, in the same region there may occur individualdepartures from sector to sector which areassociated with local physiogeography, the characterof the moisture, and other local conditions.There is also an annual variation of all constitu-ents of the thermal flux in soils, i.e. intraseasonalvariations (Gavrilova 1981). Table 1presents a detailed study of ground thermal balancesusing observations from the Ulakhan-Tarynresearch station (Gavrilova 1972).It can be noticed that, with the disappearanceof snow cover in Central Yakutia in late April thethermal flows in all of the layer become positive,At that time, a recombination of the entire structureof the soil's thermal balance takes place.The heat coming through the Earth's surface islargely used to thaw from above the soil frozenduring the winter, i.e. ice water phase transitions.A part of the heat goes to warm up the thawed layer,another part the frozen layer. Since the thicknessof the frozen soil to up the depth of attenuationof annual temperature amplitudes (10 m) is muchgreater than the thawing layer (less than m), 2then B-, in general, is larger for the season thanB+, although the level of the thawing boundary(flow of Bph) somewhat impedes the downward penetrationof the heat.In the second half of the summer the upper soillayers begin to cool. Thus, in an unfrozen layerthe flow at a depth of 0-10 cm changes its sign bythe end of July, though the total ground masscontinues to absorb heat. In September the heatloss increases in the upper 2 m, ground thawingstops, while the underlying frozen layers are stillbeing warmed up.

230Intense freezing from above soils thawed during Gavrilova, M. K., 1972, Temperature of soils underthe summer begins in the beginning of October. The different physiogeographical conditions in thesoil (about 2 m thick), unfrozen at the beginning Ulakhan-Tarvn region of Central Yakutia. Inof the month, becomes completely frozen by the end Permafrost and soil, v. 1, Yakutsk: YF SOof October, i.e. it requires one month, while thaw- SSSR, p. 35-51,ing takes place over 5 months. Also, large amounts Gravilova, M. K., 1973, Climate of Central Yakutia,of heat are released as water changes into ice. 2nd Edition: Yakutsk, Yakutknigoizdat, 120 p.The winter thermal regime begins on complerion Gavrilova, M. K., 1974, Climatic factors in theof the freezing process the of ground which thawed formation and development of permafrost rock.during the summer. Large losses of surface heat, - In Geocryological conditions of the Mongoliaat a negative radiation balance, extend to even People's Republic: Moscow, Nauka, p. 12-29.deeper layers of soil, and the entire comparatively Gavrilova, M. K., 1981, Present-day climate andthick layer of permafrost in the temperature fluc- permafrost on mainlands: Novosibirsk, Nauka,tuation zone returns its heat over the following 112 p. + Suppl.6 months (November-April)Golubev, A. V. and A. V. Pavlov, 1961, Investigationof thermal flux in soil for some typesof active surface. &Materials for the prin-REFERENCESciples of theory of permafrost of the Earth'scrust, v. 7: Moscow, Izd. AN SSSR, p. 66-118.Averkov, M. S., 1960, Annual variation of heat ex- Ivanov, N. S., 1961, Methods of measuring thermalchange in soils near Moscow, Vestnik Moskovskogo flux in rocks. In Thermal and mass exchangeuniversiteta, Ser. V, Geography, No. 2, p. 15-27. in permafrost anrfrozen rock: Moscow, Izd, ANGavrilova, M. K., 1966, Thermal regime of the Earth's SSSR, p. 91-104,surface and field and forest soils during thaw. Manual on thermal-balance pbservations, 1977:- In Proceedings of the VI11 All-Union Inter- Leningrad, Gidrometeoizdat, 150 p.departmental Meeting on Geocryology. v.4,Molochushkin, E. N., 1969, Results of a year ofYakutsk: Yakutknigoizdat, p. 194-206.observations of soil temperature on theGavrilova, M. K., 1967a, Thermal balance of a larch Muostakh Island. 2 Questions of Yakutiya'sforest on the Lena-Amgin inter-river region. Geography, v. 5: Yakutsk, Yakutknigoizdat,- In Hydro-climatic investigations in Siberian p. 127-137.forests. Moscow: Nauka, p. 28-52.Pavlw, A. V., 1979, Thermal physics of terrain:Gavrilova, M. K., 1967b, Microclimatic and thermal Novosibirsk, Nauka, 284 p.regimes of the Earth's surface and soils in the Pavlov, A. V. and E. A. Olovin, 1974, ArtificialChara hollow. In Geocryological conditions ofthaw of frozen rock by solar radiation in devel-Transbaikalie and Near-Bailal areas. Moscow:oping placers: Novosibirsk, Nauka, 180 p.Nauka, p, 148-161.

LAWS GOVERNING THE COEFACTION OF THAWING SOILS TAKINGDYNAMIC PROCESSES INTO EFFECTV.D. Karlov and V.K. fnosemtsevInstitute of Civil EngineeringLeningrad, USSRComprehensive compression investigations of the deformation properties of thawingsandy soils were carried out under static (up 0.4 to ma) and dynamic (up to 4000mm/s') loading. The experiments were made with the artificially prepared samplesof frozen sand whose porosity ratio varied between 0.544 and 1.046. The sampleswere 113 mm in diameter and 45 mm high. Maximum compaction of the thawing soiloccurred in the early stages of vibration with vibration accelerating from 0 to1000 mm/s2 and from 1000 to 2000 mm/s2. The impact of the static load is significant.Extremely intense compaction occurs under the static loads of up 0.05 toMPa. There is a linear relationship between the static load and the criticalvibration acceleration. The amount of settling of thawing sandy soils under dynamicloads is greatly affected by the grain-size composition and other soil conditions.(e.g. compactness, moisture content). It is suggested that settlement of thawingsoils under dynamic loading may be estimated on the basis of the soil compactioncoefficient when subjected to vibration, the thickness of the soil layer involved,and the values of the vibration acceleration both actual and critical. Taking intoaccount both static and dynamic loading the amount of settlement in a thawing soillayer was calculated to be the sum of the Settlements due to thawing and compactionunder static loading, and of compaction settlement due to vibratory action. Settlementof foundations may be determined by summation of settlements in individual soillayers down to foundation depth within each which of the values of dynamic actionsand the compressibility characteristics may be considered to be constant.Thawing soils may undergo great deformations due soils, it is very important to ascertain the rightto their particular postcryogenic texture which is moment to apply the dynamic load.extremely susceptible to sign-variable dynamic For this purpose three series of experimentsstresses, The laws governing thawing sandy soil were conducted. In each series of experimentscompaction under dynamic loading have not yet been frozen soil samples having identical physicosufficientlystudied and the available results of mechanical characteristics and under equally inpostinvestigations are poorly presented in both tense loads were tested. In the first series ofthe domestic and the foreign literature.experiments dynamic impact was produced directlyTo develop a reliable method for calculating the during the process of thawing a soil sample loadedsettlements of thawing foundation soils is .it nec- with a O.2-MFa static pressure. In the secondessary to establish the principle laws governing series of experiments dynamic loads were appliedtheir compressibility allowing for dynamic impact. after thawing the sample and stabilizing thecomprehensive investigations on the deformation settlement from the subsequent static loading,properties of thawing soils have been carried out which was also equal 0.2 to MPa. In the thirdin the Leningrad Civil Engineering Institute. series of experiments, the dynamic effects wereExperimental studies of the compaction of thawing produced immediately arter thawing the samplesandy soils were carried out using a specially under a pressure of 0.2 MPa with partial stabilidesignedinstallation. The main parts of the zation of the settlement of the thawing soil.installation are: a low heat-conducting con-Statistical analyses of the results of thesesolidometer,.a specially designed hollow settlement, investigations were conducted based on the criteriaa liquid thermostat, a device for static and dynam- put forth by Kohran and Fisher (Pustilnik 1968) ,ic loading, a control console, a of set measuring which established thathe difference between theinstruments, and other equipment. The basic dia- average values for the total relative settlementsgram of the installation is presented in thein the three series of experiments, with a 5% levelauthors' work (Inosemtsev and Karlov 1980). This of significance, should be considered to be insiginstallationpermits samples of thawing and thawed nificant. This means that the value of the finalsoils, both natural and with structural damage, to total deformation of thawing sandy soils is especibetested under wide range of static and dynamic ally affected by the moment (of time) when theloading.dynamic load is applied.When the foundations are arranged on thawing This conclusion makes it possible to carry outsoils, the dynamic effect may appear at different dynamic tests of frozen sandy soils after thawingstages of thawing and stabilization of ground and stabilization of the settlements due to staticdeformation. Therefore, when developing a proced- loading. Such a procedure has some importanture for estimating the compressibility of thawing advantages as compared with the procedure in which231

232dynamic impact is produced during thawing of thesoil sample. In the latter case only the totalvalue of sample settlement is determined, with nopossibility of dividing it into components suchas: thawing settlement, compaction settlementunder static loading, and settlement due to thedynamic action.If dynamic effects are produced after thawingand stabilization of sample settlement, then sucha test procedure provides all the compressibilitycharacteristics needed to calculate thawing foundationsin the presence of thawing of a single soilsample. Therefore to study the laws governingdeformability occurring during thawing of sandysoils, the procedure for testing frozen soils withthe thawing of a single sample and its subsequentstatic and dynamic loading was adopted. Such atest procedure is much more economical and providesmore certain results than testing several samplesthawing under various intensities of dynamic action.The laboratory investigation of the compressibilityof the thawing sandy soils has been carriedout in a wide range of static and dynamic loadingdepending upon the composition and the conditionof sandy soils. The experiments used artificiallyprepared sandy soil samples having various degreesof compaction (the void ratio of the soil variedfrom 0.544 to 1.046), soil moisture (the pore icevolume varied from 0.14 to 1.01, and grain size(coarse-grained, medium-grained, fine-grainedsands).Thus, an increase in vibration acceleration fromThe test results were analyzed using the proxi-2000 mm/e2 to 3000 mm/s* causes an increase inmate statistical processing (Goldstein 1973). Tosettlement several times less than the increment ofestablish probable interconnection between compresthevibration acceleration value from 1000 m/s2 tosibility of the thawing soils and the factors under2000 mu/$* (Figure 1). This is completely underinvestigation,computer-assisted regression andstandable: the thawed soil being compacted in thecorrelation analysis were run.early stage of dynamic impact changes into a moreFIGURE 1 Relationship between the relativesettlement of the thawed sandy soiland the compactness at various values ofvibration acceleration.FIGURE 2. Relationship between relativesettlement and moisture at various valuesof vibration acceleration.one can see that the main part of the settlement othawing sandy soils occurs in the early stages ofdynamic impact. A further increase in the intensityof the dynamic impact causes less Settlement.The results of the investigation of the relationcompactstate, which is characterized by less andship between relative settlement of thawing, coarsesmallerpores at the site of the thawed ice crysgrained,water-saturated sand and the initial soiltals; consequently, the conditions for particlecompactness at the moment in which varying degreesdisplacement during compaction at the next stage ofof dynamic action are applied are shown in Figure1. This is non-linear. From Figure 1relationshipdynamic loading become worse.Figure 2 shows the curves for the relationshipbetween the relative settlement of the thawed sandyI I I I Isoil samples (with the same initial compactness inthe frozen state) and the moisture content byweight at different values of vibration acceleration.An increase in the initial moisture contentby weight increases the compressibility of thethawed soils under dynamic impact and maximumincrease in the compressibility is observed with avariation of the moisture content from 0.13 to 0.20,which corresponds fo the degree of saturation G =from 0.7 to 1.0. This specified influence of moisturecontent on settlement of the thawed sandysoils is explained by the action of the capillaryforces of cohesion which prevent the soil fromcompacting during dynamic loadingslightly moistand in moist sands. And the presence of gravitationalwater, which serves as a lubricant, reducesfriction between the sand particles, thereby in-creasing, during vibrations, the compressibility ofthe saturated sandy soils whose water in is a freestate.The results acquired from experiments made withsands of different grain size showed chat with anincrease of sand grain-size the compressibility ofthe thawing soils under dynamic action decreases.Under dynamic action with a vibration intensity of

""I\23321001940I700f500I300ff000 ar 0.2 43 0.4FIGURE 3 Relationship between therelative settlement and the valueof static loading at various valuesof vibration acceleration.90070091 q2 43 44FIGURE 5 Relationship betweenthe critical vibration accelerationof the thawed soil and thestatic loading.PSOO0.490\0.480 .FIGURE 4 Impact-compression relationshipof the thawed soil.a = 0.6-0.7 g, the medium-grained thawing sandysoils demonstrated a relative compaction settlement FIGURE 6 Relationship between the criticalof 1.27 times and the fine-grained soils 1.62 timesgreater than the coarse-grained sand.vibration acceleration and the void ratio ofthe thawed soil.In addition to the factors examined above (density,moisture, grain size distribution) the valuesof static and dynamic loading highly affect thecompressibility of the thawing sand.sand particles increase, thereby affecting the valueof non-cohesive ground settlement (Ivanov 1967).Figure 3 shows the relationship between relative As a result of compression tests in the presencesettlement of the thawed sandy soil being compacted of dynamic action, it has been established thatby the dynamic action (6,) and of various values of change in the porosity coefficient of thawing soilstatic load (P). This relation is curvilinear. is a function of the intensity of the dynamicThe rel.atioa curve 6, = f(P) drops sharply when the effect (vibration acceleration). Figure 4 reprevaluefor static loading is small; with a furtherincrease in the load, the compressibility slightlydecreases. The character of the effect of staticloads on the compressibility of thawing sandy soil,sents the impact-compression relationship based onthe results of experiments with coarse-grained,saturated sands thawed under pressure 0.025 at MPa.One can see that the soil compaction begins afterwhen the dynamic load value is invariable, can be vibration acceleration attains its limit value,explained by the fact that as the static pressureincreases, the internal friction forces betweenwhich is called the critical vibration value bySavinov (1979).

234The influence of static pressure and initial soilcompactness on the value for the critical vibrationacceleration aer of thawed sandy soil shim is inFigures 5 and 6 . The regression equation of therelationship acr = f(P) for thawed coarse-grainedsaturated sandy soil is:acr = 775 + 2713P (1)ff 50004 80a 4640440where aCr is the critical vibration acceleration,m/s2 , and P is the static pressure, MPa.The correlation factor of the relationship uCr =f(P) equaled 0.975, while the verification of thehypothesis as to the existence of a link between FIGURE 7 Relationship between the void ratio ofacr and P showed that the correlation relationship the thawed sandy soil and the vibration acceleraexistsat the level of significance B = 0.001.tion.The correlation equation for critical vibrationacceleration as a function of the void ratio io,Comparison of criterion Fc with the critical one Fof the thawed coarse-grained saturated sandy soilshowed that the hypothesis adopted is negated atat the moment of applying the load C+r = f(R,a) isthe significance level I3 = 0.05.as follows:The regression equation for the relationshipR- f(a) usually may be written as follows:Bcr = 1462 - 1230 E, (2)R = a - blga (3)The correlation coefficient proved to 0.876. be Bycomparing the correlation coefficients it becomeswhere a is a free term of regression and b is theclear that the relationship between critical vibraregressioncoefficient.tion acceleration values and the void ratio ofUsing the boundary conditions (with a = acr *thawed sandy soil at the moment of dynamic loadingR + Loa) eq 3 can be rewritten:appears to be less close than that between criticalvibration acceleration and static load.R = Lo, - blg -c1The relationship between change of the voidacrratio and the vibration acceleration c1 (Figure 4)of thawed, coarse-grained, saturated, sandy Soil where Roar aCr are void ratio at the moment dynamicwas investigated using pair correlation analysis. loading and the critical vibration acceleration ofThe degree of closeness between parameters R and a sample of thawed, sandy soil, respectively.a was evaluated based on the correlation coeffic" The laws governing the compaction of thawing,ient. Its application is possible only when the sandy soil established on the basis of comprehenvalues(k, a) under consideration are random and sive investigations suggest an engineering proceddistributednormally. Verification of the hypo- ure for estimating foundation settling values atthesis related to the laws of void ratio distribu- static and dynamic loading.tion R and vibration acceleration c1 was performed The total settlement value of a thawing base atusing Pearson's coordination criterion (x2 - crit- combined static and dynamic loading can be detererion).The calculations showed that at a 5% level mined according to the formula:of significance, the accepted hypothesis regardingnormal distribution of R in the general populationis not rejected, but the hypothesis regarding thenormal distribution of a is negated.where Sth is the settlement caused by thawing ofIn this connection another hypothesis was adoptthefrozen soil and Sa is the compaction settlemented: "the distribution of a is logarithmicallyof the thawed soil at dynamic action.normal." The comparison of an empirical criterionThe settlement values Sth and Sp can be deterwithits critical value shows that the adoptedmined by a number of well-known methods (Build.hypothesis for the normal distribution of lg isStand. 11-18-76, 1974, Tsytovich 1973).not rejected. Consequently, the correlationThe settlement value of the thawed base underrelationship of the void ratio and the vibrationthe dynamic actions can be determined by layeracceleration value may be considered in thesummation according to the formula (Inosemtsev andordinate system y = R, x = lga, and the correlationKarlov 1981) :coefficient may be used to characterize the degreeof closeness in the relationship.The graph of the relation between void ratio andSa kvi hi In -"ivibration acceleration is presented in Figure 7 in1-1 ucr isemi-logarithmic coordinates. The correlation coefficientII - lga equaled 0.914.Estimation of the certainty of the R-lga rela- where hi is the thickness of the layer, i is thetionship showed that a correlation exists at the soil layer; n is the number of layers into which thesignificance level of B = 0.001.zone of dynamic compaction is divided; a,, is theStatistical verification of the hypothesis re- critical vibration acceleration estimated fromlated to the rectilinear form of the relationship laboratory testing of the samples of the i-soilR-lga was performed using the Fisher criterion. layer; ai is the average vibration acceleration in

235the i-soil layer, equal to half of the sum of theCONCLUSIONSvibration acceleration on the upper and lower boundariesof the layer; h i is the coefficient ofOn the basis of these investigations one canrelative compressibility of the i- soil layer, which draw the following conclusions:is determined by the formula:where k; is the compaction coefficient of i- thesoil layer under the dynamic actions; Roi is theinitial void ratiof the frozen soil; is Ai thecoefficient of thawing; ai is the coefficient ofrelative compressibility of the thawing soil and Pis the static load.Calculation of settlement Sa can also be made byanother procedure using not the values of the vibrationacceleration in the solution, but the areas oftheir depth curves. For this purpose, in eq. 6 thesign of the sum changes fox the integral, which incase, the number of layers into which the baseshould be divided greatly decreases. The soillayers will differ only in the deformation proper-ties. Then, in the case of uniformly distributedloading having an intensity P, of the settlement ofthe thawed homogeneous base is calculated by theformula:Sa = k, (C- B)1. The total deformation of frozen, sandy soilsamples caused by thawing, static and dynamic loadingessentially does not depend upon the moment(time) that dynamic impact is applied.2. The settlement value of the thawing sandysoils at impact loading is greatly influenced bythe composition and the condition of the sandsunder investigation. As moisture content decreasesand compactness and grain size increases, thecompressibil.ity of thawing sandy soils is reduced.3. A nonlinear relationship was establishedbetween the compressibillty of thawing, sandy soiland vibration acceleration values.4. The settlement ot thawing, sandy soils isgreatly affected by static loading an increase inwhich causes a decrease in settlement due to dynamicimpact.5. A procedure €or calculating.the settlement ofthawing bases of the foundations which takes intoconsideration dynamic actions was developed. It wasrecommended to calculate Settlement of thawing basesusing layer summation by eqs 6 and 8.REFERENCESThe values of parameters C and B are obtained from Build. Standards 11-18-76, 1974, Footings and Founexpressions:dations on Permafrost, Moscow.Goldsrekn, M. N., 1973, Mechanical properties ofsoils, Moscow.Inosemtsev, V. K., and V. D. Karlov, 1980, On theprocedure of laboratory estimating the thawingsoil compressibility with consideration of thedynamic effect: Soil Mechanics. Footings andFoundations, Mezhvuz. Proc. LISI, Leningrad.Inosemtsev, V. K., and V. D. Karlov, 1981, On theestimation of the thawing soil settlements withconsideration of the dynamic effect. Dynamics(10) of bases, foundations and underground constructions.Proc. of the All-Union Conf., Moscow.Ivanov, P. L., 1967, Compaction of loose soils bywhere z is the ordinate of the point for which the impact, Leningrad.settlement is calculated; a0 is the vibration Pustilnik, E. I., 1968, Static procedures ofacceleration at the base of the foundation; 6 isanalyzing and processing the observations,the attenuation factor of soil vibration; a, isMoscow.the critical vibration acceleration of the unyaden Savinov, 0. A., 1979, Present-day foundation consoilsample; y is the specific weight of the thawed structions under machines and their design.soil allowing for suspension caused by water; h is Leningrad-Moscow.the depth of the foundation base; is the b width of Tsytovich, N. A., 1973, Mechanics of frozen soils,the foundation base; m is the empirical coefficient Moscow.derived from the dependency curve of the criticalvibration acceleration and the static load g is thegravity acceleration.

A THEORY OF DESICCATION OF UNCONSOLIDATED ROCKS IN AREASWITH NEGATIVE TEMPERATURESI. A, KomarovGeology Department, Moscow State UniversityMoscow, USSRThe article presents the results of theoretical and experimental investigations ofthe process of desiccation in unconsolidated rocks in areas with negative temperatures.On the basis of a thermodynamic assessment of the phase equilibrium of waterin the rocks it was demonstrated that the desiccation process occurs through sublimationand desorption of ice as well as through the combined effects of theseprocesses, and occurs in two forms: voluminal and surficial. The instability ofthe surficial form is attributed to the presence of ultrapores. A capillary modelof the process is proposed, based on an arbitrary subdivision of moisture presentin the rock into 'three categories, which provide a qualitative description of thekinetics of desiccation in rocks of different composition and structure and underdifferent ambient conditions. This scheme forms the basis of a system of equationsfor a three-zone model describing desiccation in a moisture-filled rock mass. Resultsof a comparison between solutions of a simplified system of equations for a quasiisothermalcase with the experimental data are presented; they indicate a satisfactoryagreement between the two. Peculiarities of applying this solution in caseswhere the process is occurringnon-saturated rocks are discussed.Reports submitted to the 3rd ConferenceGeo- where eiinv, Xjinv indicate that the rest O i andcryology in addition to other publications (Yershov xj do not change (invariants), here Bi = Ptotalr1979; Yershov et al. 1975, 1978) have summarized and T, 2; and xj = Ray Q23, R34.analyzed basic laws governing the process of frost The values of the partial derivatives of freedesiccation in unconsolidated rocks. The article enthalpy with respect to xj are:attempts to elaborate on the physical concepts inaddition to presenting a quantitative theory as abasis for developing a prognostication techniqueto control the desiccation process at negativetemperatures.where ~ 3 4 , 023 are surface tensions at the water-PRELIMINARY STATEMENTS AND A PHYSICALMODEL OF THE PROCESSAnalysis of the physical aspect of the rock latter may be regarded as a binary solution comdesiccationprocess shows that its intensity is posed of free water and water bound by surfaceprimarily influenced by the capillary, adsorptional, forces. To describe the phase equilibrium we usedand osmotic relationships between moisture and rock. relationships elaborated in the theory of solutions.Consequently, the thermodynamic potential (free A decrease in the freezing temperature may in thisenthalpy 4)) may in this case be represented as thesum of two members, one of which depends on the Lpotentials, e;, i.e. in our case temperature (T),pressure (Ptotal), and the concentration of dissolved.substances(Z); the other depends on the(n-L) coordinates of the state xj, which definesthe system's geometry (the surface of adsorptionalinteraction a, and the magnitudes of adsorptionalsurfaces at the interfaces of the solid, liquid,and vaporous phases in the interstitial solutiona23r n34):ice and water-gas interfaces E and is the energy ofadsorptional interaction.Here and further we shall be considering thecase in which the concentration of dissolved saltsin the interstitial moisture low, is therefore thecase be regarded as a displacement of the triplepoint on the phase P-T diagram of the state of thewater. Keeping this analogy in mind it appearsfrom this diagram that the desiccation process isdependent on the relationship between the freezingtemperature (Tfr> and the temperature of the medium(T ,d) and can occur in three ways: 1) by icesublimation, Tfr > Tmed; 2) by desorption, Tfr peag anddesorption in the pores LI > uequ). Depen 1ng uponthe thermodynamic conditions prevailing in thevapor-gaseous medium and the properties of thedispersive system, these processes can take one oftwo forms. The first is typical for systems inwhich the surficial form of phase transition is236

237stable (frontal transition). The other is distin- is a further development and generalized of formguished by the presence of a phase transition zone Krisher's bicapillary model (1961) as applied to(voluminal transition).Detailed analysis of possible causes for theinstability of the surficial form (Komarov 1979)has shown that apparently the formation of a zonethe case involving the presence of the solid watericephase in the pores. The concepts incorporatedin the model are based on the assumption that unfrozenwater is present in the rock in partlyis due to capillary effect occurring at relatively between the blocks of mineral particles (microhighnegative temperatures when ultrapores with a aggregates indicated by circles) and ice (blackradiusr < m are present in the rock. In this ened areas) and partly in ultra-capillaries andcase, the difference between surface tensions at pores permeating the particles themselves (Figuredeveloped water-ice and water-air interface areas la). In the first case the equilibrium is influexertsa significant effect on the process kinetics, enced by the interface curvature with respect toresulting in the formation of an evaporation zone.As temperature decreases, the process kinetics isice and vapor, while in the second case it isexposed to the effect of adsorptional forces.largely influenced by adsorptional surface forces, Furthermore, the interaggregate moisture (in thewhich results in degradation of the evaporationzone. In the absence of ultrapores, for examplecapillary of the radius) is assumed to be mobilewith respect to the moisture present inside thein sands, the zone is essentially absent.aggregates (capillary R1). Thus, the overallThe dehydration kinetics will be discussed with moisture content of unconsolidated rock can berespect to a capillary model of the process, which arbitrarily subdivided into three categories (thefFIGURE 1 Three-capillary model and schematicfigure of dehydration process.

!383rd category being moisture in the solid state, with the surrounding air, rather than with ice,capillary R3). Accordingly, to describe thewhile on the opposite side the water collar conkineticswe may use a diagram of three capillaries tinues to be in contact with ice (Figure lb). Theof different diameter, linked with one another equilibrium condition for the water collar meniscusthroughout the length of the wall in the absence with ice and vapor will be written ($23) as =of resistance to moisture transfer across these ($34)023/034. Since in every case $ < 1 amd 023 >walls (Figure ld,e,f).u34, consequently $34 > $23, which stipulates aThe main features of the physical image result- difference between chemical potentials ALI =ing from this model are as follows:RT(ln$su - ln$23) > 0 on the opposite sides of theAt the initial moment of time the level in all water collar. This difference in potentials causesthe three capillaries is flat (Figure la). Once melting of the ice localized within the space ofthe condition P /Ps

239ported towards the vapor-gas interface by variousmechanisms: a) in the desorption zone it isprimarily by concentrated vapor diffusion (coefficient%); b) in the phase transition zone bythe above mechanism in combination with migrationof unfrozen water and a succession of microevaporations-condensations.The total transfercoefficient Keff in this zone may be one or twoorders higher than h* In the glacial zone themoisture transfer is negligible.In the proposed model in order to describemoisture transfer we have made use of sorptionalkinetics equations that have coefficients that areonly slightly dependent on moisture, rather thanequations €or moisture conduction. This stems fromthe fact that, on the one hand, the values mois- ofture concentration in the solid or liquid phase donot represent transfer potentials at negativetemperatures and, on the other hand, because theessence of the physical phenomena occurring in theentire region involved in the dehydration processare reflected better according to the conceptsa thermogradient coefficient.The content of unfrozen water in desorptionzones and phase transitions is dependent on thepartial pressure of aqueous vapors and temperature.Consequently,-awl a-c (.gqT .+ (5) aT p aT E -To find the derivative (aW,/aP), it is necessary tohave an equation or experimental data for the desorptionisotherm. The derivative (aW3/aT)p can beobtained if we have the curve of the phase compositionof moisture. For a sufficiently great numberof rock types undergoing desiccation at negativetemperatures the contraction is insignificant (i.e.y~ # yl(W)) and, consequently, it can be writtena (ylW) /?IT = yl (aW/a-c) ; otherwise 3 (yltl) /aT =y1 (w)aw/aT + w a (ay/aT)If the process is accompanied by filtration,expressed in the models. Desiccation occurs in thephase transition zone through the liquid phase by i.e. molar gas or water transfer, it is necessaryway of desorption of unfrozen water films when there to include convective components of heat and moisiscontinuous replenishment due to ice meltage. ture transfer in the left-hand part of equationsThe equation describing sorptional energy and 2-5. To close the system, equations of continuitykinetics for the identified zones in a unidimen- and movement must be added.sional formulation assumes the form:As far as formulation of the problem for nonmoisture-saturatedrocks is concerned, it does notappear possible in this case to close the basicequation system unless additional hypotheses areintroduced. A promising possibility involves thefollowing assumptions (desiccation of coarse-unconsolidated rock): 1) the shape of ice inclusionsin the rock is globular; 2) the radius of theinclusion decreases in the course of the processwithout changing the shape of the inclusion; 3) thedensity of the mass sources in the unit volume ofrock and the function of their distribution areknown (in the case of irregular distribution). Tofind the moisture-content fields requires solutionof the diffusion equations in spherical coordinatesin the presence of a mobile phase transition boundary(for unitary ice inclusion) and for diffusionequations in which the source in the right-handTart is written in orthogonal coordinates (for therock layer as a whole).SIMPLIFICATION OF INITIAL SYSTEM OFEQUATIONS AND COMPARISON OF DATAThe system is closed by the equations of state Analysis of the above system of differentialand bonding energy. The latter with respect to the equations 2-9 shows that, given the correspondingdesiccated zone corresponds to adsorptional equil- boundary conditions, even numerically it appearsibrium and with respect to a phase transition zone, to be extremely difficult to solve this problem.to the ice-unfrozen water equilibrium.Considerable simplification of the initial systemis achieved whenever the process of kinetics isP = P(p,T) (7) fully determined and controlled, either by heat ormoisture transfer. The latter case, as demonstratedby the joint analysis of experimentallydetermined heat and mass flows, is characteristicof natural conditions during the dehydration process(Yershov et al. 1975). In the absence of an

240external temperature field (the natural geometric the 1st period, as well as under the condition.gradient in rock masses is very insignificant, viz. 3. (a f 0; b = 0 - degeneration of the phase"C/cm) this process occurs under near isother- transition zone). Dehydration of hydrophilicmal conditions (for a fixed unit of moisture mass coarse-disperse rock and fine-disperse rocks a atthe value of the derivative ((dP/dT),+m)). Another temperature range below -7°C + 10°C.extreme case (dP/dT),+O occurs, for example, under 4. (a = 0; b = 0 - degeneration of the desorpvacuumdrying conditlons.tion and phase transition zones). Dehydration ofThe degree of approximation in the two extreme pure sands or artifically hydrophobized rock.cases can be assessed by considering the heat and The first two cases were described by sorptionalmoisture balance for an isolated elementary non- kinetics equations whose mass sources are linearlyshrinkable volume of rock (Komarov 1979). The distributed over the zones subject to the conditionbalance equation assumes the form:of moisture flow conjugation at the zonal boundaries;the third case by an analogous equation inthe presence of a mobile boundary (Stefan-typeproblem); and the fourth case a by diffusionequation in the presence a of mobile boundary(Stefan-type problem).(10)Experimental verification of the relationshipswas carried out at three installations whose designexperimental procedures and technique for deter-As seen from equation 19, the value of themining moisture-conductive and adsorptional characderivative(dP/dT), depends upon: the relativeinertia of the temperature and moisture fieldteristics were described in papers (Yershov 1979,Komarov 1979). The setups made it possible to(Kt/%); the relationship (l-n)/n which relates tothe fact that heat is, for the most part, transmeasurecontinuously for several months the variabilityranges of the medium parameters: O>t >ported through the skeleton of the rock, while-25"C,moisture is transported through the pore space; andO

241Geological Fa culty (manuscript in VINITL, No.24776). (In Russian)Komarov, I. A., 1979, Investigation of heat andmass-exchange in dehydration of dispersivesystems under below-zero temperatures (inapplication to rocks): Candidate's dissertatiolthesis, LTIKhP, Leningrad. (In Russian)Krisher, O., 1961, Scientific principles of dryingtechnology: Moscow, Foreign Literature PublishingHouse. (Russian translation)Yershov, E. D., 1979, Moisture transfer and cryogenictextures in dispersed rocks: E~OSCOW,Ma mscow State Univ ersity Publish ers. (In RUB siYershov, E. D., Gurov, V. V., Komarov, I. A., andKuchukov, E 1 Z., Experimental investigations ofheat and moisture transfer in the of case watersublimation-desublimation in finely.dispersedrocks, Materials of Third International Conferenceon Geocryology, v. 1: Ottawa, Canada'sNational Research Council.Yershov, E. D., Kuchukov, E. Z., and Komarov, I. A.,1975, Ice sublimation in dispersed rocks: Moscow,Moscow State University Publishers. (In Russian)

THERMAL INTERACTION BETILTEN PIPELINES AND THE ENVIRONMENTB. L. KrivosheinResearch Institute on Management forOil and Gas Pipeline Construction, USSRAspects of thermal interactions between large-diameter underground pipelines andthe environment are considered. Consideration of this topic is necessary forachieving design solutions under northern conditions. Criteria of choice areformulated. A classification of various methods for pipeline laying is developedfor northern regions and appropriate operating conditions are discussed. Numerical;simulations have been carried our with the of aim deter ining the permissiblenegative temperature of the external surfaces of under ound pipelines from anecological point of view. The influence of water migr tion on the rate of freezingaround the pipe is evaluated. Soil expansion during the transport of chilled gashas also been evaluated. It has been shown that the actual thermodynamic propertiesof the gas make a significant contribution to the level of gas cooling at compressorstations. A method for determining the optimal thickness of insulation along thelength of a gas pipeline is suggested with due consideration of environmental protection.Generalized relationships for heat transfer in underground gas pipelines aregiven, in the case of both constant and variable temperature (where apparatus forair cooling is used). Results obtained were applied to the design of gas pipelinesin the Soviet North.The experience of operating large-diameter gas the pipeline-environment thermal interaction.pipelines (1420 mm in the USSR North) has shownthat the temperature of compressed gas can reach40-45'C. Therefore, air-cooling apparati (AAS) areSTATEKENT OF THE PROBLENpresently being installed at compressor stations.In the winter the minimum allowable gas temperature, The thermal interaction between large-dim leterfollowing AAS, is set based on the freezing stab- pipelines and the ground has a number of featuresility of the pipe steel, the temperature gradientbetween compressor stations (CS) and the geocryologicalconditions along the route (Krivosheinwhich stem from the actual thermodynamic propertiesof gas under high pressure and low temperatures,the conjugate nature of gas-soil heat transfer, in1982). Pipes currently in use are designed to addition to the ecological limitations imposed byoperate at gas temperatures up to -1O'C. A pipe- environmental protection.line may undergo annual variations in gas tempera- Construction and operation conditions for largetureequal to 50-55'C. The allowable temperature diameter pipelines are related to their temperaturegradient for both operation and construction of1420 mm gas pipelines, at a working pressure 7.5 off"9a at first and second category sites, 58OC isregime. As diameter and working pressure increase,the stability of buried pipelines has become acrucial factor for reliable gas transport (Batalin(i.e. it is approximately equal to the temperature 1979). When gas which has been chilled a to negagradientunder operating conditions). As the range tive temperature is transported (chilling can beof the gas working pressure increases the safety done of either year round or in the winter AAC), usingpipeline operation is reduced: longitudinal temperaturedeformations increase and, a as result,there is danger of a loss of stability; underthe pipeline's surface also acquires a negativetemperature. Therefore, when a pipeline intersectsmarshy land and water obstacles ice forms on thepositive ground temperatures corrosion of the pipe- surface of the pipe, the surrounding ground expandsline intensifies; mass transfer processes in soilalso intensify.At sites made up of continuous subsidenceand the pipe heaves upwards towards the surface.This can result in blockage of ground water runoffand other disturbances in the zone of pipelinepermafrostit is necessary to ensure a gas trans- environment interaction. Pipeline icing increasesport regime in which the pipe-ground thermal flux buoyancy, which must be compensated for by addiapproacheszero. This means that the gas temperatureshould correspond to the ground temperature ata depth of pipeline axis at various times. Such ational ballast. Disturbance of the ecologicalequilibrium might well result in irrevocable damageto the natural landscape and reduction of pipelinesolution has been adopted for the Urengoi-Pomary- reliability. A number of methods of restraint andUzhgorod pipeline, which is subject to permafrostconditions. In order to determine the requiredin some cases elimination of ecological disturbancesduring construction and operation are alreadylevel of gas cooling, the temperature changes overdistance, the CS and cooling station capacities,etc., it is necessary to take into considerationwell known.Experience in designing northern pipelines in theUSSR and abroad has shown (Krivoshein et 1975) al.242

243that the problem in question can be solved: byapplying methods €or laying pipe which eliminateline (cold-resistant steel pipe, supports, etc.)and cost-effective operation (cooling devices,or limit the thaw or freezing depth of the bedrock; etc.), the character of gas temperature changesby chilling the gas to a level that preserves the along the length of the pipeline and gas temperafrozenbedrock underlying the pipeline during the ture changes over time.total period of operation; by combining methods of The main factors are the following: depth ofconstruction and operation which ensure "thawingfreezing"of the soil in natural ranges; by usingground thaw under (or above) a pipe in relationshipto the temperature of the pipe's exterior surfacelocal chilling devices.(TN); the magnitude of ground heave, the extent ofThe prognosis for thermal interaction between hydrological disturbance-in the vicinity of thethe gas transported and the environment plays a route; the temperature of the pipe's exteriorsignificant role in the choice of technical solu- surface in marshy districts and water crossingstions.(TN). Depending on the specific conditions, oneWe shall first consider the criteria choos- for of the factors above is the dominant one, anding methods of laying pipe and operating regimes others are subordinate.in the North and, secondly, analyze the results ofIn case of poorly timed start-up of the coolingcalculations used to prealct thermal and mechan- equipment (TN > O'C), the depth of ground thawical interaction between the construction process serves as a validating criterion for the method ofand the environment.laying pipe. The depth in question should providestability of the pipeline. operation in a non-calculated regime (in the absence AAC), of andCONSTRUCTION SOLUTIONS WHICH TAKE INTOrestoration of the ground temperature regime afterACCOUNT ENVIRONMENTAL FACTORSstart-up of cooling operations.During transport of AAC chilled gas, all of theIn above-ground construction of gas pipelines main factors must be taken into account, moreover,the thermal impact on the ground is eliminated.in the presence of annual negative gas temperaturesLimitation of this influence in required ranges one must also consider ground heave and TN themay be achieved by a combination of the following: value, As experience in designing northern pipethermalisolation and gas chilling by AAC; gas lines has shown, sections of frozen and thawedchilling to annual negative temperatures by AAC soils having different properties alternate andand cooling devices, local cooling of soil near the this makes different technical solutions necessary.pipeline using cryoanchors, thermopiles, cooling To select levels for chilling.gas, Table 1 preagents,etc. As is well known, the North of West- sents a classification of pipe-laying techniques.ern Siberia is characterized by a considerable In northern areas design and operating regimesvariety in soil temperature and humidity and a wide (mainly thermal conditions) are inter-related.spectrum of cryogenic processes. Therefore, con- Sectors having a high level of ground subsidencestruction techniques and the choice of operating and in which thaw below the active layer is notregimes is an involved scientific and engineering possible (type If) represent the greatest danger.problem.The minimum allowable mean annual temperature ofInvestigations and design calculations carried gas in thawing sections (type 11) is derivedout at different institutions, as well as analyses from the formation of frozen patches underofforeign experience have shown that in northern neath the base of the active layer (Kudryavtsev etregions it is necessary to combine various techni- al. 1974).cal solutions depending on the specific geocryo- For sections of continuous (or prevailing) frozenlogical conditions.soils (type I and type 1111, cooling the gas byrefrigeration (in the summer) and by AAC (in thewinter) to seasonal ground temperatures at theCRITERIA FOR GAS PIPELINE: CONSTRUCTIONAND OPERATING REGIMESdepth of the pipeline's axis is acknowledged as themost rational solution. Results of mathematicalsimulation performed at a number of institutionsThe main problem is either to maintain the prescribedtemperature and humidity of the bed or to(Ivantsov et al. 1977) and foreign experience showthat temperature for gas cooling, in the course oflimit these factors to a range that will ensure the annual cycle, varies from -1O'C to -6'C. Thestability and integrity of the pipeline, as well as institute, GIPROSPETSGAS, has designed a refrigeraanunviolated environment. The choice of construc- tion station for the Urengoi-Nadym pipeline whichtion method and operational behavior of pipelines will cool the gas to -2°C. The selection of allowinthawed soils depends on the following: sub- able temperatures of a pipe's exterior surface (TN)sidence (at T!: > O°C) or heave (at TN < O°C) of affects the thickness of insulation for pipelinesthe bedrock; the character of the propagation of designed to operate at negative gas temperatures.ground subsidence or heave in the vicinity of the Actual thermodynamic gas properties affect thepipe route; the vertical cryogenic structure of bed- choice of temperature. For chilled gas pipelinesrock, soil temperature, depth of the active layer, having a negligible gas-soil temperature gradient,the location of the ground water horizon and thedegree of marshiness of the adjacent territory; thethe throttle-effect is the determining factorinfluencing gas temperature changes occurring overdegree to which the pipeline route has been studied distance.taking into account the reliability of prediction For determining allowable negative temperature,for permafrost conditions at the onset of operation; from the point view of of ecology, (TN)~~~the geography of the district; the presence of thematerials needed to ensure construction of pipe theinvestigations of thermal interaction betweenpipelines and soils have been conducted (Kovalkov

244TABLE 1 Classification of Construction Methods and Operation Regimes€or Northern Gas PipelinesTemperatureMethods of laying range of aRoute conditions Pipe Operation regime gas pipelineContinuous frozen Laying pipe below TN = Tgr(h0) Tg(T) "Tf + Tinavsoils (type I) the active layerThawed soils with a) Laying pipe in ht R+ > 1R-l T (TI = Tw"gislands of frozen thawing soils Amsoil 11) (type(10 i 1) - ATdrFrozen sites, sub- h,(T+) 5 hdop Tg('r) 5 Tfject to groundsubsidenceGround not subject arbitrary Tg(T) = T, +to subsidence(10 15) - ATdrb) Laying pipe above ht ('r+) 5 hest(-c+) Tg(') = T, - Tinavground with thermalisolation on groundsubject to subsidenceContinuously frozen a) Underground pipeground with- taliks laying in frozen soil TN = Tgr(ho) Tg = Tpr(ho)(type 111)in thawing soil iL R' z In-1AmTg = Tgr(ho) - ATdrb) Above-ground pipelaying with thermal TN = Tgr(ho) Tg 2 0°Cisolation on thawingheaving soilet al. 1977).Mathematical formulation of the problem forinteraction of a chilled gas pipeline (TN < O°C)includes equations describing external medium andgas with the corresponding boundary conditions thatexpress the boundary thermal balance. Usually theproblem is three-dimensional, nonlinear, due toStephan's conditions (in equations for externalmedium) and due to terms for gas flow. Because ofsubstantial temperature gradients in longitudinaland transverse directions (to the pipeline axis)the problem may be differentiated as flat for soilaround the pipe and one-dimensional for gas flowacross the pipeline (Ktivoshein 1982, Agapkin etal. 1981).Within the limitations of traditional assumptionsthe heat zone of the soil is usually describedby a system of equations:B2, E4 dxaTi =B3 Ti TnsB5 XiaTi = 1ris(Ti - Tg)B6 Y-aT2 -x2 an QfTI = T2 = Tf ,d5where I = 1,2: 1 is thawing soil; 2 is frozensoil; B2, E3 are, respectively, boundaries alongthe axis of the pipe and beyond Its influence(natural conditions); Bq is the boundary of soiland the pipeline; B7 is the boundary of soil zoneswith different thermo physical properties.Applying well-known analytical methods ofsolution (Krivoshein 1982, Agapkin et al. 1981)one encounters insurmountable difficulties. In theUSSR Academy of Sciences algorithms have beenderived for numerical solution of such problems(Alekseeva et al. 19741, however due to the absenceof precise solutions and reliable experimental datait has not been possible to evaluate the accuracyof these numerical calculations. In papers

24 5(Kovalkov and Krivoshein 1977, Kovalkov et al.1982) a Lukyanav hydrointegrator was used. Nonrectangularblocks were used for the sectioncontiguous to the pipe, while concentrated andhidden thermal capacity was calculated proportionallyto the area of blocks.Initial conditions were obtained by solving forthe natural ground field over an 8-12-year periodduring which boundary conditions simulating thermalinfluence of the pipeline were not imposed. Thisexperience made it possible to assume that duringconstruction the vegetation cover is disturbed andre-establishes only 5 years following pipelineconstruction.~6 4 2 0ANALYSIS OF RESULTSSome results of multi-variant calculation areshown for non-insulated (Figure 1) and thermal isolated(Figure 2) pipelines. Paper (Kovalkov et al.1977) suggests a possible criterion for allowableenvironment disturbance in the zone affected by achilled gas pipeline.An impact is considered permissible if, due tothe influence of the chilling source (the pipe),the level of ground waters (LGW) in the pipelineconstruction zone does not exceed the annual LGWin marshy areas of the same territory. A necessarycondition for choosing the required temperature(TN)min is location of the upper freezing boundaryin the vicinity of the hydrologically active layerin winter minimal ZGW. The annual average temperatureT ( N ) = ~ -2°C ~ ~ for the northern zone fields isderived from the above conditions.Approximate analytical solution for the choiceof ( T N ) assumes ~ ~ ~ the following form:FIGURE 1 Combined graph of the position of freezingfront in soil for the zone of laying-up a nonisolated1420-rmn gas pipeline in the Surdut area bythe 1st of November for the 9th year of operationand under different gas temperature (Ty = Tg).4 2 0These studies (Krivoshein 1982, Krivoshein 1979,and others) are based on a ground thermal transferequation. The additional thermal input, stemmingfrom ground water filtration flow in the layerbetween the ground surface and the upper pipe'ssurface, was not taken into account because reliableexperimental data on mass transfer soil characteristicsare not available.The effect of moisture migration on the velocityof soil freezing has been estimated. It has beenshown that for actual soils (E" 5 0.1; KO f 2; w

24 6= 1*09ps3(1 +E)pW.[a(wr-wo)+B(2wr+wo)l;[A(w~+w~)+~%(w~-w~)~ - (wn-w0). +x6a;(wn-wO)*+ 8amA(wn+wo) -+ A26WoWnFor evaluation calculations were performed usingthe following initial data:am = 2 - 10-4m2/t; E = 0.97; wo = 0.17; w, = 0.27;JON THE EFFECT OF REAL GAS PROPERTIESKrivoshein (1982) reviews the investigationscarried out in the USSR on the problem of thethermal interaction of pipelines with environment.On the basis of solutions already obtained, thedecrease in gas temperature (due to the effect ofJoule-Tompson) for a 1420-m pipeline with workingpressure of 7.5 MPa was evaluated. They havedemonstrated that along the section between CS thedecrease in temperature amounts to T-lO'C. Takinginto account the ecological criterion obtainedabove, the relationship for the level of gas coolingat a CS assumes the form (Krivoshein 1979):Tn = [ ~ T- N aT (1+exp[-(Al+a)] +gr A1 + ap, = 2830 kg/m3 ;KDjwtx, = 1.74" magrad , (J = 333.6 -; 5, = 1000 !% *kgm3 'T = -1., -2; -5; -1OOC.PThe results of the calculations are given inFigure 3. It is obvious that if Tfl = -2'C, thenthe value of ground expansion doesn't exceed 0.3during the winter. Under the above indicated condition,pipeline stability and normal passage ofground waters are maintained.I 10where:b=XRGZzo(P,T)/2gZDf2; n=1,2.DETERMINATION OF OPTIMAL GAS TEMPERATURE PROFILESAND THERMAL INSULATION TEICKNESS ALONGTHE LENGTH OF A PIPELINESince the gas temperature decreases along a pipelineand since it is necessary to provide the conditionTs=TN at the surface of pipe-soil contact,the thickness of the thermal insulation shouldincrease with distance. Krivoshein (1979) demonstratesa solution obtained by variational calculationfor determining optimal gas temperatureprofiles and thermal insulation thickness. Usingcomputer-assisted numerical calculations it hasbeen shown that optimal profiles for gas temperatureand thermal insulation thickness are close tolinear:T ;Tn- (Tn-T)XOP t k LCONSIDERATION OF PIPE-GROUND THERMALTRANSFERFor extensive operation of a pipeline under Ts=0°C one should use a regression equation, derivedfrom mathematical simulation and field measurements:FIGURE 3 Swollen soil-dependence of time underdifferent temperatures: 1) -10°C; 2) -5'C;3) -2°C; 4) -1°C.where(13)

24 7For chilled gas pipelines data from Figure 4 maybe used wherecoordinates; Zo = Zo(P,T) - compressibility factor;thermal transfer coefficient from ground toalr, X - hydraulic resistance coefficient; X , =X;(;=l 2) - ground thermal transfer coefficient;Xis - insulation thermal transfer coefficienrpsk, pw - density of soil skeleton and water; wo,wnat - moisture level of soil at the rolled boundary,and under natural conditions; 6is - thicknessof insulation;€ - porosity of soil; 7' - time;a+(-) - warming (cooling) impulse (szt(-) = T,Heat losses of pipelines under transient conditionsT+(-)); 5 - coordinate of moving boundary.are defined by the method (Krivoshein et al. 1977).Thermal conditions for gas pipelines equipped withAAC are calculated using the method (Krivoshein etINDICESal. 1981) which takes into account the dynamics ofground phase transitions and seasonal variation in T, M - thawing and frozen zones; N - outsidegas temperature.layer of insulation; 0,l - internal. and externalThe results described above serve a as founda- pipe radius; n, k - beginning and end of pipe;tion for the themo-physical calculations used in natural conditions; in av.an.cond. - mean (average)designing Northern &as pipelines in the Soviet annual conditions; n - ground surface.Union.REFERENCESAgapkin, V. If., Krivoshein, B. L., and Jufin, V. A.,1981, Heat and hydraulic calculations of oilpipelines and product lines: Moscow, Nedra.Alekseeva, G. V., Birykova, N. J., and Koshelev,A. A., 1974, Development and use of finaldifferencealgorithms for solving the Stephanproblem. 2 Asymptotical methods in the Kheoryof systems, ed. 7: Irkutsk, University.Batalin, J. P., 1979, Experience of gas pipelineconstruction Vyngapur-Chelyabinsk. Ed.,lnformneftegasstroi.Ivantsov, 0. M., Dvoiris, A. D., Krivoshein, B. L.et al., 1977, Construction efficiency for low- .temperature gas pipelines-Design and constructionof pipelines and gas-oil field facilities:MOGCOW, NIPIESUoil-gas-stroi.FIGURE 4 Variation of Kirpichev's criterion in the Kovalkov, V. P., Krivoshein, B. L. et al., 1977,annual cycle for a subground gas pipeline in the Freezing of underground gas pipe and forecastUrengoi area under different gas temperatures €or of disturbance of underground water flow:the 6th year of operation:Stroitelstvo gasoprovodov, no. 7.1) Tg = -20°C; 2) -15'C; 3) -10°CKovalkov, V. P., and Krivoshein, B. L. et al.,1982, Interference of oil and gas facilitiesNOEENCLATUREwith cryogenic rock, Summary of reports(Geocryological approach in regions of Extreme%,ai,j - coefficients of mass and thermalNorth, Moscow.conductlvlty, respectively; Bi - Bio criterion; Krivoshein, B. L., 1979, Investigation and optimi-Cp,C~ - specific thermal capacity of gas and soil; zation of heat regimes of gas and oil mains:D~(P,T) - throttling effect; D,f - diameter andIzvestia, USSR Academy of Sciences, Energia iarea of pipe section; G - mass flow of gas;transport, no. 4.hall,hnat-depthofaLlowablegroundthawandunderKrivoshein, B. L., 1982, Thermo-physical calculanaturalconditions; ho - depth of pipeline axis; tions of gas pipelines: Moscow, Nedra.K - coefficient of thermal transfer; Ki, KO, L, - Krivoshein, XI. L., and Agapkin, V. M., 1977.criteria of Kirpichev, Kosovich, and Lukov; L -Transient thermal loss of underground pipelines,length of pipe; P - pressure; Of, 0-latent heat of1 FJ. vol. 33.ice thaw per unit of volume and unit of frozen Krivoshein, B. L., Agapkin, V. M., and Dvoiris,soil; q - thermal flow from pipeline to soil or inA. D., 1975, Construction and operation of pipereversedirection; R - gas constant; %,Ri - pipelines in permafrost: Moscow, VNIIOENG.radius; pis, rv - values of thermal resistance of Krivoshein, B. L., Kovalkov, V. P., and Sumarokov,insulation and vegetative cover, respectively; Ta, V. S., 1981, Temperature range of undergroundTg, T,(T~) - temperature of air, gas, and ground, gas pipelines transmitting chilled gas:respectively (i = 1 - thawing soil, i = 2 - frozen StroitelsKvo truboprovodov, no. 1.soil); Tnt, Tb - ground temperature at the neutral Kudryavtsev, V. A., Garagulya, L. S., Kondratieva,layer level and at the temperature of beginning of K. A. et al., 1974, Basic permafrost prognosisground moisture freezing; nTdr - drop in gas temp- for engineering-geological investigations:erature due to throttling effect; x,y - CartesianMoscow, University.

DEFORMATION OF FREEZING, "AWING,AND FROZEN ROCKSYu. P. Lebedenko, L. V. Shevchenko, 0. A. Kondakova,Yu. V. Kuleshov, V. D. Yershov, A. V. Brushkov,and V. S. PetrovGeology Department, Moscow State UniversityMoscow, USSRThe paper examines the deformation of earth materials during rhe processes of heatand mass exchange while undergoing freezing, thawing, and in the frozen state. Studyof the deformation of the materials during the processes of freezing and thawing hasshown that variously directed and nonuniform strains develop in unconsolidatedmaterials. Shrinkage strains are directed downward due to migration of water towardthe freezing front. Heaving strains are directed apward due to the 9% increase inthe volume of pore water on freezing and due to the accumulation of segregation iceat the expense of water which has migrated from the unfrozen zone. The accumulationof segregation in enhancing the upward deformation of the earth materials was alsofound in thawing soils where there a was frozen zone in a gradient temperature field.During a comprehensive study of the deformation of frozen materials in an isothermaltemperature field, the samples were tested for uniaxial compression with and withoutpossible lateral expansion. Investigations revealed bi-axial relationships betweenthe pattern of deformation, the final magnitude of deformation, the composition andstructure of the materials and the magnitude of the deforming load and rate ofdeformation.INTRODUCTIONDeformation of freezing, thawing, and frozenearth materials is an important problem for bothgeneral and engineering geocryology, physicochemistry,and frozen soil mechanics. The solution be thrust upwards. Thawing ground heave may be, inof this problem depends upon thorough investigation general, presented as follows:of the theoretical basis of the evolution of cryogenicprocesses (heaving, shrinkage, settling,structurization, and texturization, etc.) andtransformations in cryogenic composition, structure,where hI represents deformation due to migrationand the properties of frozen soils. It is alsoWice accumulation in the frozen zone; hexp is deformimportantfor applied geocryology to provideation of ground surface due to expanslon in thereliable support for engineering projects in frozen,thawed zone; hshr is the deformation of physicofreezing,and thawing grounds. Thanks to thechemical shrinkage of the thawed zone due to dehyeffortsof many researchers from various countries,dration; hset is thermal settling deformation dueconsiderable theoretical and practical evidence hasto the decreasing ground volume resulting frombeen accumulated revealing the processes of heavingthawing of pore and segregational ice.in frozen ground, of settling in soils, and ofHeaving strain in thawing soils due to themechanically-induced deformation in frozen soils.accumulation of migration ice is possible only ifAt the same time, deformation in thawing materials,there is a temperature gradient in the frozen zone.This occurs,.usually, when, due to water migrationand the accumulation of segregation ice, a heavingin which water exchange between the thawing andfrozen zones subject to ice segregation occurs,have not been sufficiently studied; likewise theinterrelationships between the deformation offrozen soils and water migration, structure, andtexture formation within the field of mechanicalforces also require further study. Physico-earth materials within a gradient temperature fieldmigrates towards lower temperatures, resulting insegregation ice and deformation. In thawinggrounds, water migration and ice segregation alsooccur in the frozen zone. The ground surface maystrain develops in the local ground layer, in whichcase its surface may subside due to strain orsettling and shrinkage. The ground surface riseswhen the expansion strain in the thaw zone occurssimultaneously with the accumulation of migrationchemical factors associated with the deformationice. Ground thaw coupled with positive strain isof frozen, freezing, and thawing soils must alsofollowed by extreme thermal settling caused bybe examined more thoroughly. This paper deals withthawing of pore and migration ice. As a result,these problems.the ground surface settles. Thus, thaw deformationExperimental and field observations demonstratedepends on the sum total of variously directedthat heaving may occur not only during freezing butstrains that result in both the fall and rise ofalso when the ground is frozen in or a state ofthe earth materials.unilateral thaw. Unfrozen water in frozenDeformation processes occurring in materials of24 8

249of highest shrinkage they seldom make up more than20% of the total value of negative strains.In freezing Soils, unlike thawing ones, the valueof heaving strains can in general be expressed asfollows:FIGURE 1 Diagram of relationship between strainsinduced by the accumulation of migration ice (hIw),expansion (hexp). shrinkage (hshr), settling (hset),and heaving (hheav) in soils of different composition:a) sandy loam; b) loam; c), d), e) kaolinite,polymineral, montmorillonite clays thawing in opensystems; f) kaolinite clay thawing in a closed system.different granulometric and mineral composition andsubject to diverse thermal and water condirionsduring thawing were studied. The results revealedthe following: As soil dispersity increases fromsands to clays, the flow of migration water and theaccumulation of segregation ice in frozen groundincreases. In clay of different mineral composition,water migration and the accumulation ofsegregation ice increase when such soils increasetheir content of kaolinite minerals (Figure 1).Deformation resulting from the accumulation ofsegregation ice in the frozen zone of thawing claysand sandy montmorillonire loams comprised 5-10% ofthe total value of positive strain causing heaving,while in kaolinite clay the deformation due to thisprocess comprised 80-90% of the total value. Conversely,in montmorillonite clays the expansionstrain occurs more frequently (80-90%) while inkaolinite clays they constituted about 20% of thetotal positive deformation. Sandy loam and loamsare considsrably less subject to expansion: in athawing loam the magnitude of expansion was half ofthat in a kaolinite clay, while sandy loam did notreveal any expansion at all (Figure 1).Our observations indicate that expansion deformationin soils thawed in an open system is alwayshigher than in a closed one. This can be attributedto the fact that when water flows in from the outside,part of the external migration flow is expendedon the accumulation of segregation ice in thefrozen zone, and parr of this water goes to enhanceexpansion deformation. When thawing occurs withina closed system, the strains in the thawed soilcaused by desiccation and shrinkage increase whilethose due to swelling decrease.Positive strains in thawing soils which resultin heaving usually level off due to developingshrinkage and settling strain. Unlike freezingsoils where practically the en'cire freezing layerundergoes shrinkage, thawing soils shrink only nearthe border of thawing and their shrinkage lastsonly a short time. This phenomenon can be explainedby a flooded horizon appearing near the interfaceborder at the expense of the thawed layers of ice.It was found that shrinkage strain during thaw islower in an open system as compared to thaw in aclosed system (Figure Ib,e). Shrinkage strains donot level heaving much; in montmorillonite groundswhere hheav(g%) is the value of ground heaving dueto the 9% increase in the volume of frozen porewater (mass expansion); hIw is the value of heavingdue to the accumulation of segregation ice; andhshr is the value of physico-chemical shrinkagestrains in the thawed ground due to desication.The calculated value of heaving due to watermigration is equal tohIw = 1.09 Kan * Kw 6:h grad. t - T ,where K, is the coefficient of anisotropy allowingfor the inclination angle of ice layers; is thecoefficient of water diffusion, m2/s, and 6Ph isthe rhermogradienr coefficient, I/grad C. Theheaving value due to the 9% increase of pore watervolume during freezing can be expressed as follows:where WF is the water content of the ground's minerallayers, which is quantitatively equal to the watercontent at the phase interface boundary, fractionsof unit, and WUnfr is the amount of unfrozen waterin the soil, fractions of unit.The shrinkage that takes place in the thawedportion of the soil can be calculated a5 follows:where K,hr is the anisotropic shrinkage coefficientshowing the contribution of vertical shrinkage tototal volumetric shrinkage; 6 is the coefficient ofrelative volumetric shrinkage of the soil; AW = W -Wshr is the difference between the initial watercontent of the soil and the water content at thefreezing front; and A< is the layer undergoingdehydration, m. In terms of the density distributionof the soil skeleton, the value of shrinkagecan be calculated as follows:in €where ysk and ysk are, respectively, the initial andfinal values of the weight density of the soilskeleton before and after freezing. When materialsof different composition, structure, and propertiesfreeze under diverse thermal and moisture conditionsthe total value of heaving depends on the patternsfor development of individual deformations inducedby frozen pore water, segregarion ice, and shrinkage(Figures 2 and 3). On the whole, ground heaving canbe expressed as follows:hheav= 0.09 (WE - Wunfr )AE + 1.09 Kan * K,

250FIGURE 2 Diagram of the relationship betweenstrains in frozen soils of different composition inan open system: a) sandy loam; b) loam, c) bo-Linite clay; d) polymineral clay; e) montmorilloniteclay.204.612Q40FIGURE 3 Diagram of the relationship betweenstrains in samples of kaolinite clay with differentinitial density a) and c) compaction load up to0.1 MPa; b) up to 0.2 ma; d) up to 0.8 MPa: freezingin an open (1) and in a closed (2) system.O kUl 20x- I0- 2*- 3“”43%rwFIGURE 4 Displacement-induced water redistributionin frozen soil samples with different mineral composition:1-polymineral clay; 2 -kaolinite clay;3-montmorillonite clay; 4-water content beforethe experiment; 5-displacement plane.This technique for assessing the values ofexpansion deformation in freezing and thawing earthmaterials was tested in both laboratory and fieldstudies and yielded satisfactory results.The dynamics and laws governing the developmentof stresses in freezing and thawing rocks due toheat and mass exchange, as well as physico-chemicalprocesses occurring during phase transitions, indicatethat such strains are interrelated with soildeformation and soil structurization. Greaterstrains develop in clays, while lower ones areobserved in loams and sandy loams. Freezing-inducedstrains increase in open systems as compared withclosed ones, and also under higher external pressures.An increase in both the external load andthe integrity of structural bonds in the freezingsoils results in reduction of deformations; moreover,when critical load values are attained,deformations fade out to zero. Further increase inpressure results in compaction of freezing andfrozen materials.These studies on ground deformation in agradient-free thermal field show that an externa !1load on a frozen soil results in migration ofunfrozen water and ice segregation, in addition ttransformation of the soil micro and macrostructure. Water redistribution and micro- andmacrostructural transformarion were observed durboth the slow displacement of frozen soils andcomaression cornpaction.Examination of the moisture distribution curvesbefore and after the experiment (Figure 4) showedthat maximum ice accumulation caused by displacementstrains in soils of different mineralogicalcomposition occurred in the displacement region:in kaolinite clays (Win = 39%, y,k = 1280 kg/m3in polymineral clay (win = 292, ysk = 1410 kg/m5,in bentonite clay (Win = 87.5%, ysk = 800 kg/m3.(The experiment was carried out at -3’C, Tdispl =0.2 ma). The thickness of the ice accumulationzone decreased from kaolinite (0.017 m) to polymineral(0.016 m) and bentonite clay (0.0035 m).Maximum desiccation (AWdes) was found in the upperand lower parts of the samples; it comprised 5.5%in kaolinite, 3.5% in polymineral, and 1.5% inbentonite clay. The desiccation zone also decreasedin thickness from kaolinite to polyminera1and to bentonite clay, comprising 0.025;0.017, and 0.0125 m, respectively. Variationsin the thickness of the desiccation zone andthe extent of desiccation can be attributed rothe unequal water conductivity of these clays.The diffusion coefficient in kaolinite clay isthe largest, attaining 3.5.10-9 m2/s, which iswhy the desiccation zone in kaolinite clay is thegreatest. This coefficient is the lowest inbentonite clay (& = 0.5*10-3 m2/s), which hasthe thinnest desiccation zone and the least amountof desiccation. The largest migration flows of waterare formed in kaolinite clay, namely, 12.6 * 10”kg/m2 s; in polymineral clay they are 8.9 *kg/m2 s; in bentonite clay they are equal to 1.42lop7 kg/mz * s. As soil density increases and soildispersity decreases, the migration flow is reduced,Microstructure studies of montmorillonite, polymineral,and kaolinite clay samples before and afterthe experiment show that the shape and size of iceinclusions undergo changes during the process of

25 1FIGURE 5 Deformation in frozen soils (-1.5'C) underdiverse external loads: I, 2 - montmorillonite clay;3, 4 - polymineral and kaolinite clays; 5, 6 - sandyloams with different degree of pore saturation withwater (q = 1 and q = 0.6); I, 11, 111, IV - compactionload equal to 0.3 MPa, 0.6 MPa, 0.9 ma, respectively.FIGURE 6Rheological curves of frozen soil flow at-3'C: 1 - clay (W = 41.6%; ysk = 1690 kg/cm2>; 2 -loam (W = 22.6%; Ysk = 1880 h/cm3); 3 - sandy loam(w = 21.9%; y k = 1740 kg/cm3); 4 - sand (W = 20.0%;ysk - 2010 kg$cm3).deformation; isometric and irregularly shaped iceinclusions, typical of the initial samples, aretransformed into micro-streaks of ice.Our investigations have shown that the progressionof water transfer and structural transformationsin frozen rocks induced by external loadsdepends on their deformability. Analysis of thedeformability of frozen soils under external. loadshas demonstrated that deformations in less dis-persed soils are markedly weaker (Figure 5) e Themore dispersed a soil is, the longer the deformationlasts. For example, deformation in sandyloam under an external load of 0.3 MPa is completedin 8 days; in the case of clays, accordingto their dispersity. the deformation processrequired 10, 11, and 13 days (curves 5, 3, 4, 2).The effect of dispersity on soil deformation iseven more manifest when The soil pores are notcompletely filled in. When the degree to whichpores are filled is 0.6 (Figure 5, curve 6) in apolymineral sandy loam, this soil reveals anotherpattern of deformation that can be explained by thedeformation stages of the soil's ice-mineralskeleton and its pore space.Soil deformability is greatly affected by themineral composition of soils. In comparing curves3, 4, 5 one can see that Soils with larger contentsof flexible laminated particles of hydromica (polymineralclay and sandy loam) undergo greater deformationthan kaolinite clay composed of rhe largeranisodiametric particles. In terms of theirrelative compressibility, the soils under study canbe arranged as f0llows: montmorillonite clay > polymineralclay > kaolinite clay > polymineral sandyloam.The investigation of the compression of frozensoils at constant rates of deformation (within therange from 8.5 * lom6 to 1.7 * s-'), and withpossible lateral expansion, showed that the curvesdepicting the relationships between flow stress andthe deformation rate were similar for frozen claysand sands (Figure 6). Linear approximation of theserelationships clearly demonstrates an area of lowrates with high plastic viscosity coefficients andan area of high rates with low values of thiscoefficient. The transition zone is confined to adefinite range of deformation rates (from 8.5 to85 lov6 s-'); it seems to be related to the relaxationnature of the mechanical properties of the poreice cementing the mineral particles of the Soil.The invesrigation of the effect of relativestrains (ET) on rhe moments when the strains becomestable has revealed some interesting regularities.In the case of clayey (clay, loam) and sandy (sand,sandy loam) frozen soils, as the deformation rateincreases, i.e. a5 the soil's elasticity response tocompression increases, the value ET of increases.A similar regularity was observed when both rhetemperature of Soils and their number of monovalentcations decrease. The generation of strains infrozen clays and sand varies. In frozen clays thevalue of ET at low deformation rates is half of thatat high deformation rates. In frozen sands, despitethe large strains, this relationship is less evident,and within the range of -1.5"C, the value ET is ofclose to unity. This peculiarity may be primarilydue to the difference in the compressibility of themineral skeleton of soils. The compression testscarried out have yielded results that agree withthis supposition.It was also found rhat at temperatures low as as0" to -1O"C, the flow in the soil samples almostalways began when the sample began to increase itsdiameter. In sandy soils the degree of compressionaK the time Khe diameter began to increase (Ea) waslower than that in clayey Soils. In the area ofhigh deformation rates, in the case of clays, attemperatures below -1.5"C the values of Ed do notchange much (about 2%) (Figure 7). As the temperaturedecreases, the value of (ET-Ed) increases,which attests to increased volumetric plastic

252FIGURE 7 Relationship between the degree of compressionin clay and deformation rate by theinitial moment of lateral expansion (unblackenedsigns) in samples and by that of flow (blackenedsigns) at different temperatures. Symbols: 1,2,3,4 - soil temperature equal to +.so, -1.5'; -3"and -1O"C, respectively.strains resulting from the increase in the sample Deformation of freezing, thawing, and frozen soilsdiameter. At the same time, at temperatures above is interconnected with processes of heat and mass-1.5'C and at deformation rates below 8.5 *exchange, of structurization, and texturization.s-I the flow of clay for a certain time did not Gn the one hand, soil deformation can be induced byaffect the sample diameter, i.e. the process was heat and mass exchange; on the other hand, deforofthe "compression" type.These regularities and the results of microstructurestudies of deformed soils make it possibleto idenrify the main characteristics of the processof accumulation of volumetric plastic strains infrozen fine-grained soils under uniaxial compression.In the first place, two processes occurduring volumetric deformation (dilatation) : "compressional"constriction and plastic dilatationcaused by an increase in the sample diameter. Theimportance of the first process increases withgreater soil dispersity, elevated temperatures. andlower deformation rates. In favorable instancesthis process may dominate. In the second place,during compression deformation of clayey soils,their mineral and ice components undergo a degreeof differentiation (when the initial cryogenictexture is bulky) which depends on the criticalcompressibility of the soil's mineral skeleton andthe volumetric plastic deformability of ice stemmingfrom its relaxational nature. Due to thisfeature of ice, this process is time-dependent. Inthe third place, plastic dilatations of soilsoccurring during the enlargements of their diameterresult from interrelated dislocations of consolidatedaggregates (of clay) or of separate particles(sand), The mechanical resistance of soil to suchdisplacements (soil viscosity) depends directly onthe phase composition, the relationship between thedeformation rate, and the time of strain relaxationsin the ice. As the dispersity of soilsdecreases and the deformation rate increases, thelocal continuity of samples may be interrupted morefrequently (the appearance of microcracks).Therefore, our studies of the mechanism and lawsgoverning deformation in freezing, thawing, andfrozen soils of different granulometric and mineralcomposition, structure and properties, under diversethermal, water content, mechanical, and dynamicexternal conditions have demonstrated the following,mation and stresses themselves induce water migration,and, on the whole, result in heat and massexchange. In each type of deformation (free orinduced), the development of soil deformationsderives from their micro and macro structure.

MIGRATION OF ELEMENTS IN WATER INTAIGA-PERMAFROST LANDSCAPESV. N. MakarovPermafrost Institute, Siberian BranchAcademy of Sciences, Yakutsk, USSRThe peculiarities of the migration of elements in water in the main taiga-permafrostlandscape types in Northeastern Yakutia are examined. Zonal and azonal classes ofgeochemical landscapes associated with permafrost and bioclimatic peculiarities aredistinguished on the basis of the conditions of migration of elements in water.Differing intensities of the migration of elements in water as between permafrostand non-permafrost zones were demonstrated, Both surpluses and deficits of certainelements were identified and also paragenic associations of elements characteristicof specific geochemical landscapes.The identification of taiga-permafrost landscapesof the north-eastern part of Yakutia isbased on principles developed by Perelman (1966).The largest generally accepted categories of geochemicallandscapes are represented by bioclimaticunits that define the natural conditions and thecharacter of migration of substances. Accordingto water migration conditions associated withbioclimatic and permafrost factors, zonal classesare identified as: acid (H+), acid gley (H+-Fe*), calcium (Ca*) and azonal-sulphate (H+ -SO:'). In addition to azonal landscapes of sulphateclass occurring in areas of sulphidemineralization, azonal landscapes associated withicings and characterized by contrasting geochemicalfeatures can also be distinguished.Taiga-permafrost landscapes of class (H+) orthoeluvialon granitoid and effusive formationsgenerally form under conditions of highly unconsolidatedrelief. These landscapes occur inmedium-high and high mountains composed of granitoidand effusive rock. Autonomous landscapes ofthe acid class occur on a weathering debris crustand on mountain-tundra and mountain-taiga rockyprimitive soils which form on them.The unconsolidated relief and ledge rock governthe poor development of vegetation, low degree ofmarshiness and intensive water exchange. Typicalplant forms are: fragmented moss-lichens, thicketsof ledum-cladonium cedar creepers in the lower partformation in stages of biotite into hydrobiotite,accumulation of iron in the form of films andscums of amorphous and weakly crystalline oxides,and the transport of sodium, calcium, potassiumand silica from the eroded layers. The soils arerepresented by crushed-rock supes having highacidity (pH 3.4 - 4.7) and a rather high organicmatter content in the form of coarse humus (up to7-8%) *The landscapes under consideration are characterizedby the propagation of ultra-fresh chloridehydrocarbonate,mixed in composition, cations oflow-acid waters, poor in iron (less than 0.1 mg/R)and organic matter. The chemical composition ofsurface waters (averaged over 100 samples), takenfrom 15 granitoid formations, is as follows:HC0373 C1 27Na58 Ca22 Mg20pH 6.0 Eh 0.54BWithin zones of exo- and endocontacts ofgranitoid strata, mineralization of natural watersis increased to 30-40 mg/R and sulphate-hydrocarbonatewaters appear. Natural waters oflandscapes of this type are characterized a byrelationship between the ions HC03 > C1 and Na >Ca, Mg. As a result of weathering of granitoidsand eruptive rock, the composition of solutes (ionsink) sodium, calcium, and magnesium hydrocarbonatespredominate.of slopes and bush-lichen tundras on northfacingIn order to quantitatively estimate the waterslopes.migration of elements for the landscapes underThe physical weathering that leads to the formaconsiderationwe shall determine the value of iontion of large-size placer debris and kurum-talussink for which qualitative characteristics of theis especially pronounced. Rapid water seepagemigration capacity of elements may be obtained bythrough the coarse upper debris of the kurum layerscomputing the water migration coefficients.provides for downward placer migration of elementsAccording to our calculations, the annualwhich are transported downwards along the section.surface run-off of solutes from the granitoidWe will examine the chemical weathering characstratavaries between 1 and 4 t/km2/year andteristic for landscapes of this type, usingaverages 2.2 t/km2. Dividing the value of iongranitoid formations as an example,run-of€ by the average weight density of theSurface weathering leads to the formation ofregion's granites, 2.60, we obtain a value for theiron-bearing surface-eroded layers of loosechemical denudation (0.85 mklyear), which is 4-5granite. The main hypergenic changes of granittimesless than that for granitoid rock in moderateoids consists of fragmentation and disintegrationclimatic zones (Strakhov, 1965).of rock, partial destruction of feldspars, trans-253

254The values for ion run-off that we obtained are Temperate zoneI.much lower than those hitherto available for grani-1Kxtoids in the north-eastern part of the USSR, 16-170 1t/h2 /year (Walpeter 1972). This, to our know-100 Iledge, has been overestimated a by factor of 3U I D 2because the investigator did not take into account m3atmospheric fallout of solutes (Janda 1971). Therock masses, in which the ion run-off has beendetermined, lie along littoral zones of the of Sea 10 IOkhotsk where the atmospheric fallout rate of saltsis 10-12 t/km2/year (Climate Atlas of the USSR,1960).We have computed coefficients (Kx) for migrationin water using the formula reported by Perelman 1(1966):m * 100/XKx = ’a*nxOJwhere m, is the volume of the element in the waters,g/R; a is water mineralization, g/R; and nx is thevolume of the element in rock, %.The values mx and a were derlved analytically, /while n, represent the amount (in percentages) of 0.01 Iacid rock in the lithosphere (Vinogradov 1962).The rows representing the migration of elementsLin water are listed in Table 1.TABLE 1 Mobility of Elements in Water ofGranitoid StrataValue of coefficient ofIGgration migration in water, Kxrate100 10 1 0.1 0.01Very high C,C1,climatic zones, groups of elements having similarmobility can be distinguished, i.e. unique geo-9Bi,Tl,chemical associations. Migration contrast can becompared using Kk, the coefficient for the range ofAg , Sbcontrast equal toHighSn,B,Mg,Ni ,FK =MediumZn,Pb,Cu, kV,Na,Y,Ca,K,K,of granitoids in subarctic zoneof granitoids in temperate zoneCr ,Be ,140,MnMaximum migration contrast (Kk is larger than 10)is typical for Sn, As,Ti, B, Ag, Sb, Hg. ContrastWeakmigration Ga,Ba, (Kk = 2-10) is observed in Ni, Pb, Cr, V,Si ,CoY, and Be.Very weak Ti , ,A1Nearly all the elements refer to very strongFe(Hg, As, Bi, Ti, Ag, Sb) and strong migrators (Sn,B, Ni, F) in graniroids of north-eastern Yakutia(cf Table 1).The set of elements that possess high mobilityAs compared to the rows compiled by Perelman and maximum contrast for migration in water can be(1966) for the weathered crust of silicate rock in regarded as a unique paragenic landscape associaatemperate zone, the zone of granitoid hyper- tion.genesis, which is situated in the subarctic clim- Taiga-permafrost landscapes of acid class (H+),atic region, tends towards inertness of some of the orthoeluvial in terrigenous stratified formations,macrocomponents, namely sodium, calcium and silicon. are widely distributed throughout regions havingThe abovementioned values for ion run-off also lend low and medium height mountains. Autonomous acidsupport to a reduction in the amount of chemical class terrains are distributed in weathered debrisweathering of granitoids under conditions of hypergenesis.Figure 1 shows a value for the migration ofelements in water, derived using Kx, for naturallandscapes in different climatic zones. Within therange of the migration distribution of chemicalelements having varying degrees of contrast incrust and the mountain-taiga and northern taigapermafrost soils which have formed on them. Watershedareas are composed of dense sandstone rock andsaddlebacks occur adjacent to stratified shaleoutcrops. Sandstone rock is characterized by coarseshales and on slopes produce typical rocky talusmade up of large-clod materials, Destruction ofSubarctic zoneFIGURE 1 Contrast range of element migration ingranitoid landscapes of different climatic zones.Fields of distribution of chemical elements:1 - non-contrast migration (Kk = 1);2 - contrast migration (Kk = 2 - 10);3 - high-contrast migration (Kk = more than 10).

255clayey and aleurite shales leads to the formation temperate climatic zone, is characreristic forof deluvial gravels.gold, mercury, tungsten, and beryllium (a sharpThe thickness of the seasonal thaw layer on increase of migration activity, Kk more than 100)south-facing slopes is 1.2-1.4 m. On north-facing and for zinc, silicon, and cobalt (substantialslopes it is practically absent, with frozen rocks decrease of migration mobility, Kk less 0.01, thanor ice occurring directly below the moss cover. cf. Figure 2).Mountain-taiga suglinok soils have an acid Taiga-permafrost landscapes of the calcium classreaction (pH 3-41, a high concentration of exchange (Ca*) on carbonate stratified formations. Thesebases within the upper humus layer and considerable landscapes provide more favorable conditions for(up to 25%) organic matter content in the form of the biological cycle, producing larger amounts ofcoarse humus.biotic material; there are more grasses and bushesLandscapes of this type are characterized by theoccurrence of ultra-fresh hydrocarbonate waterswith mixed composition of cations. The averagecomposition of natural waters in taiga-permafrostterrain (over 4,000 samples) is:0.028HC0380C118S042pH 6.3 Eh 0.48BNa37 Ca33 Mg30As compared to taiga-permafrost landscapesoccurring in volcanic bedrock, the mineralizationof natural waters increases in this case a byfactor of 1.5-2.0, while the anion-cation ratioremains the same.The composition of the ion run-off is predominantlycalcium, magnesium and sodium hydrocarbonates.The ion run-off value is, on the average,estimated at 4.25 t/km2/year; chemical denudation,at 1.6 per year (with an average weight density ofstratified rocks in the Verkhoyansk complex of2.65); this comprises about one-fifth of themechanical denudation value which is typical ofterrigenous rocks in the Verkhoyansk complex.The rows for the migration of elements in waterfor stratified rocks of the Verkhoyansk complexare presented in Table 2.TABLE 2 Mobility of Elements in the Water ofTerrigenous Stratified FormationsCoefficient values forNigration migration in water, Kxrate100 10 1 0.1 0.01in the plant cover, the amount of humus increasesin the soil, its peat content decreases and carbonategleization develops. The waters are moremineralized and contain more calcium and le55 acidorganic matter and the pH reaction approaches theneutral one.HC0397 Cl 2 SO41i-4°*150Ca50 Mg30 Na20pH 6.8 Eh 0.27 BThere is a substantial increase in the ion runoffrare, amounting to 28 t/km2, or nearly twicethe mechanical one (Seimchan River, locationChapaevo).In a weak alkaline medium many metals (copper,lead, nickel, titanium) exhibit low migrationcapacity and are transported from soils in smallamounts (Table 3).The low migration capacity of most of theelements in the landscapes has been confirmed bythe evaluation of "soil mobility" made using thevalue of eluvial-accumulative coefficient (Mikhailova1964) which indicates very low mobility formolybdenum, zinc, lead, copper, erc. (Table 4).Temperate zone01c "" PVery high C,Cl,S,F,B,Ag,Na,Au,HgHighW,Be ,As,Mg,Ca,Tr,Sr ,Ba,lb,MediumVeakVery weakMnSn,Sb,Ti,Pb,Cr,Cu,Zr,V,Ti,NiZn , FeCo,Ga,Al ,SiA maximum range of contrast for migration in FIGURE 2. Contrast range of element migration inwater in taiga-permafrost landscapes of stratified terrigenous landscapes of different climatic zones.terrigenous formations, as compared to those a of Legend same as in Figure 1.

TABLE 3 Mobility of Elements in the Water ofCarbonate Stratified FormationsCoefficient values forMigration migration in water, Kxrate100 10 1 0.1 0.01Very highC,S,Ag,c1High Cd 9%MediumWeakVery weakNa,Ti,SnCu,Ni,Mo,Cr,Pb,Zn,Ee,B,V,GaTABLE 4 Soil Mobility of Elements in CarbonateFormationsIntensity index of element migration (K el. -acc.)Highly mobile, Mobile Weakly Inert,below 0.35 0.35-0.7 mobile, above 1.40.7-1.4Ge, E, bh Co, Sn, cu Y, Gay V,Cr, NiPb, Zn, Ti,MOThe saturation of the soils of taiga-permafrostcarbonate landscapes of the calcium class withmicroelements has a favorable impact on soilfertility. During geochemical exploration interrain such as those under discussion, it isadvisable to employ lithachemical methods becausein the soils which overlie deposits contrastingresidual haloes of most of the ores arise.Taiga-permafrost laadscapes of the acid gleyey(H+-FeZ") class, accumulative superaquifer arefor the most part characteristic of low-lying areas,composed of loose, stratified, terrigenous, cainozoicaccumulations and peat-bog soils forming onthem. The latter develop underneath the plantcover which consists of carex-veinik and bush-ledumkassandra-carex-moss-bogspecies, An especiallysevere soil climate forms underneath the mosscushion and the peat horizon, which subsequentlyhinders warming of mineral soil in the summer.This is because peat-bog soils in most cases havean acidic reaction within the peat layer (water pH5.2-5.8) that is ChSe to the neutral one occurringin the underlying mineral layer of soil (6.4-6.7 pH). Within the peat layer the organic mattercontent, in terms of humus, varies from 26 to 70%,while that of gross phosphoric acid ranges from0.26 to 0.46%. The sum of exchange bases variesfrom 30 to 100 mg-equ per 100 g of dry substance,of which 75-93% is CaZ+ and 7-25% Mg2+.This type of landscape is widely distributed in256river valleys and lowlands. In pH and the degreeof mineralization, natural waters approach watersof acid class. The abundance of organic matter(peat, residuals of vegetation) produce a regenerationmedium. Gleization processes, well developedin the soils of such landscapes, are responsiblefor the typomorphic nature of the Fe* ion.All the landscapes of this group are characterizedby seams of bedrock underlying a cover offriable cainozoic formations. The influx ofelements originates mainly from contiguous landscapes.There is practically no removal of element:because the processes are dominated by accumulationCa,Mg,Mn, (except for alluvial landscapes). Bedrock, inplaces where the thickness of the cainozoic formationis small due to the formation of saline bulbson top of the ore bodies, is another possiblesource of element accretion.Plain-type landscapes, widespread occurrence ofTi hover rocks and geocryological and hydrogeologicalconditions make it possible to consider theselandscapes as superaquatic. The processes ofmechanical migration of substances everywhere,except for river-beds and floodlands, are greatlyweakened. Physical and chemical and biogenicmigration is very pronounced. The rate of watermigration of microelements is increased (Table 5).TABLE 5 Basement Levels of Elements in AccumulativeSuperaquatic Landscape WaterMigrationValue of coefficient of watermigration, KXrate 100 10 1 0.1 0.01Very highHighMediumWeakVery weakHgMONiZnAgMn,Y,Pb,Cu,Cr,Ba,V,Ti,Co,GaThe presence of weak-acid, ultrafresh, chloridehydrocarbonatewater with mixed cations is typicalof these landscapes. The composition of naturalwaters of the Verkhne-Adychanskaya depression istypical (average over 19 samples):The ions characteristically have the followingratio: HC03 > C1 > SO9 and Na+ > Mg* > Ca*.In peatland waters, the mineralization sometimesincreases substantially (up to 100 mglk), while theacidity is decreased due to the presence of humicacids (pH 5.2 or less).This type of landscape is littoral and is charac-

257terized by several other hydrochemical properties. of elements that are characterized a by high con-The proximity of a sea, resulting in greater input trast range of migration in the subarctic zone, inof salts with atmospheric precipitation, is respon- comparison to the migration mobility in the tempersiblefor the occurrence of chloride-hydrocarbonate, ate climatic zone. "Abundant" elements are thosepredominantly sodium surface and ground waters with with Kk in excess of 10 while deficient elementsa relatively high mineralization and a weak acid ofnear-neutral pH. These are exemplified by springwater and shallow lakes in the eastern Primoryelowlands, in the Kolyma River basin (the averagefor 52 samples from an area of about 2,000M0*070HC0351 C1 49Na71 Ca22 Mg7pH 6.7 Eh 0.5Bkd):In the surface water composition, the chlorineioncontent averages 25 mg/R (12-50 mg/R), whereasin landscapes of this class occurring further inland,the background content of chlorine-ion is4 mg/R. The relatively high concentrations ofchlorine-ion accounts for the decrease in thebiogeochemical activity of silver, lead and copper(Table 6).Table 7 gives the geochemical characterizationof the landscapes under study, the geochemicalspecialization of a given landscape being definedon the basis of paragenic associations, i.e. groupsinclude those with Kk below 0.1. The geochemicalspecialization of the main types of landscape iswell defined.The absence of a number of elements is determinedby the very small contribution of underground watersin the surface run-off, by low mineralization ofatmospheric precipitation and by weak developmentof the technogenic processes.The behavior of concentrating elements, characterizedby a high migration contrast range, thatform paragenic associations, for example, gold,mercury, antimony and tungsten in landscapes ofterrigenous mesozoic formations, is determinedmainly by the metallogenic properties of thegeological formations, the high regional percentagesof the lithosphere.The paragenic associations of elements isolatedhere are typical of certain landscapes and indicatenot only geochemical but a150 ore specialization.The abundance or shortage of a number of elementsdetermines the balneological or economic value ofa landscape.TABLE 6 Biochemical Absorption of Microelementsin Accumulative Superaquatic LandscapesRegionCoefficient of biological absorption10 10-1 1-0.1Verkhne- Cd,Ag,As Mo,B,Zn,Pb, Li,V,Ga,Ti,Adychanskaya Cu,Ni,Sn,Cr, Y,Mn,ScdepressioncoPrimorye As ,Mo Mn,Zn,Co,Nb, Ni,Li,Sn,depression Ag,Cr,B Y,Pb,Ge,V,GaTABLE 7 Geochemical Characteristics of the Main Types of Landscapesof North-East YakutiaTerrigenous 0.028 4.2 H+ Au,Be,W,Hg, Si ,Zn,Co,AlPIZNa,F,Cu,Ag,MTI,Ba,As,Sb,SnGranitoid 0.019 2.2 H+ Bi,Sn,Ti,As, Na,Ca,Si,A,MZHg,Ag,Ni,Be,CrCarbonate 0.150 28 .o Cat+ Cd,Mn, Ti , ,Ag Pb ,Zn,Ni ,Ti,PZ Hg, Sn V,Ga,B,MoTerrigenous 0.023 7.0 Hf-Fe* Mo,Be,Ni,Si, Ag,Pb,CuKZ (0.070) Ti,Co,Ga,Sn

REFERENCESClimate Atlas of the USSR, 1960, Leningrad,Gidrorneteoizdat.Janda, R. J., 1971, An evaluation of proceduresused in computing chemical denudation rates.Bull. Eeol. SOC. her., 82, No. 1, 67-79.Mikhailova, R. P., 1964, Some relationships ofmicroelement abundance in soils of the taigazoneof the Urals in relation to geochemicalexploration. & Soil-geographic and landscapegeochemicalresearch. Moscow, Izd-vo MGU, p.113-120.Perelman, A. I., 1966, Landscape geochemistry.Moscow, Vysshaya shkola, 392 p.Strakhov, N. If., 1965, Foundations of the theoryof the lithogenesis. Moscow, Izd. AN SSSR,P. I, 212 p; P. 11, 574 p.Vinogradov, A. P., 1962, Average abundances ofchemical elements in main types of eruptiverocks of the Earth's crust. Geokhimiya, No. 7,p. 641-664.Walpeter, A. P., 1972, The character of present-dayprocesses of weathering in the north-easternparr of the USSR. Current problems of thegold geology in the north-eastern part of theUSSR. Trudy SVKNII, Magadan, v. 44, p. 157-173.

INVESTIGATION OF THE DEFORMATION OF CLAYEY SOILS RESULTING FROMFROST HEAVING AND THAWING IN FOUNDATIONS DUE TO LOADINGM. A. Malyshev, V. V. Fursov. and M. V. BaluyuraInstitute of Civil EngineeringTomsk, USSRThe relationships between the deformation of clayey soils beneath loaded foundationsand the number of freeze-thaw cycles, soil composition, pressure, depth of the foundationfooting, and ground water levels with respect to the depth of freezing weredemonstrated. When the pressure on the foundations increases, heaving begins at themaximum depth of freezing penetration beneath the foundation footing. Intensity ofheaving decreases. An increase in the depth of the foundation within the freezingzone reduces the impact of heaving at the ground water level with respect to thedepth of freezing. Loaded clayey foundation materials whose settlement had stabilizedprior to freezing experienced additional settlement after further cyclical freeze-thawin the materials. Additional compaction of the soils, as a result of repeated freezethawin the loaded foundation materials, leads to reduction in the deformation.The aim of the investigation to was study clayeysoil deformation under the influence of seasonalfreezing and thawing. To that end deformations inloaded foundation beds of settlement plates andlaboratory tests of soil-bearing capacity anddeformation under the influence of freezing andthawing have been investigated.The construction site with foundations is locatedin Tomsk. The soils represented are alluvialloams and sandy loams with soft plastic and fluidconsistency. These loam are dusty and carbonaceous,70-95% of the light fraction consists ofquartz and feldspar; in the colloid-dispersivefraction, kaolinite prevails. For the freezingperiod the ground water level was at 1.8-2.8 m.The Soils were soft, water-saturated, and stronglyheaving. The depth of seasonal freezing at theregularly freed of snow site during the investigationtime in 1978-82 was 1.8-2.2 m.The area of the settlement plates 10,000 was cm2(Figure I), their depth was 1.0 and 1.5 m, and thepressure on the soil was 0, 0.1, 0.2, and 0.3 MPa.Four pf the foundations, constructed in 1978, hada depth of 1 m and the pressure of (ma) : F1 =0.05; F, = 0.1; F, = 0.2; FL, = 0.3. In 1979 sixmore foundations were put up, two of which had thedepth of 1 m and the pressure of: F5 = 0; Fg =0.3;and four foundations at the depth 1.5 of m had thepressure of: F7 = 0; Fa = 0.1; F9 = 0.2; Flu =0.,3.The field test procedure is described below(Malyshev and Fursov, 1982).Before setting a foundation, a hole 50 nun indiameter and 3.0 m deep was bored below the foundationfooting. According to the selected type ofsoil, the degree of moisture and plasticity weredetermined. The surface of the foundation beds wasleveled. Foundations were set on a 1-cm-thicklayer of cement and sand mortar. The side surfaceof the settlement plate and the metal frame wereprotected against freezing together with the soil.To measure vertical displacement Maximov's deformationmeters and clock-type indicators were used.In experiments the leveling 'cy anchors and markson foundations was made. The depth of soil freezingwas determined by Ratomsky frostmeters, and thesoil temperature by soil thermometers. Up to thegiven pressure, foundations were loaded 0.2 in MPaincrements until settlement had stabilized. Forthe entire freeze-thaw season observations oftemperature, depth of freezing, soil deformations,"-0"""""- YT-FIGURE 1 Schematic drawing of the settlement plate1- model of the settlement plate 1.OX 1.0% 0.4 m;2- frame for load; 3- load; 4- film, covered withsolido1 and a board box; 5- loam 1~=0.4-0.7;6- loam IL = 0.75-1.0; 7- depth of freezing;8- ground water level.259

2 60FIGURE 2 Vertical displacement of settlement plates at a depthof 1.5 m in freezing and thawing of foundation beds:1,2,3,4 - foundations F7, Fa, F’J. and Flo; 5 - depth offreezing.and foundation displacement were made, At thebeginning and at the end of winter the level ofground water was measured.Observations in 1978-82 indicated that foundationsset at the same depth but under differenrsoil pressure were characrerized by heaving, thebeginning of which did not coincide with the soilfreezing of foundarion beds and was different invalue. See also Shvets and Mel’nikov (1969),Kiselev (1971), and Karlov (1979). Foundationswith higher pressure on the soil had a thicker layerof frozen soil below the foundation footing, so thatfoundations did not heave, and the total value ofheaving was decreased. For instance, when thesettlement plate pressure increased from 0 to 0.3MPa, the maximum value of heaving of foundationsset at a depth of 1.5 m decreased from 2.8 to 0 cm(Figure 2). Of foundations with the same soilpressure, but set at different depths (1.0 and 1.5m), the greater capacity of the frozen soil belowthe footing, before heaving began, was inherent tofoundations that were deeper. These foundationshad a ground water level at the end of winter thatwas approximately 40-80 cm lower than the depth offreezing. At higher ground water levels, with thedepth of 1.7-1.9 m from the surface and with freezingto 1.9 m in 1979-80, foundation F6, set at adepth of 1.0 m with a footing pressure of 0.3 ma,heaved 7.4 cm. The heaving began when the firstbelow foundation footing reached 40 cm and sharplyaccelerated during further freezing up to theground water level. Under the same conditions,foundation Fg, set at a depth of 1.5 m and underthe lower pressure of 0.2 ?Pa, heaved only 0.5 cm.The foundation displacement curves are presentedin Figure 3. The greater heaving of foundationF6 as compared with foundation Fq is accounted forby the increase of water migration through thefreezing soil, while the pressure influence issharply decreased because of the redistribution inthe frozen soil under the foundation footing. Thus,the level of ground water being in the frost zone,the influence of pressure on the decrease of heavingis more effectively manifested in the hightemperaturelower part of the frozen layer.According to observations on the displacement offoundations with different pressures it can bestated that, at the beginning of heaving, thenormal pressure under the foundation footing resultingfrom freezing of 1 cm soil for foundations set

261FIGURE 3Vertical displacement of settlement plates and marks - heavemeters in freezingand thawing of foundation beds' soil.1 - surface mark; 2 - foundation Fg; 3 - foundation Pg; 4 - mark at the depth 1.0 m;5 - depth of freezing.at the depth of 1 m, is approximately equal to 0.01 reaches 0.7 cm, the rise of marks reached the levelto 0.007 MPa/cm, and for foundations 1.5 at m it is of 8.1 and 16.8 cm. The depth of freezing does notnot more than 0.005 MPa/cm. These values were increase. In thawing the layer between the surfacerecorded when the level of frozen soil under the and the foundation footing, the foundation settlefootingwas approximately 0.4-0.8 m. The influence ment was 3.2 cm, that is it was equal to the valueof pressure on deformations of loaded foundation of frost heaving, the settlement of marks 0.8 wasbeds during the freeze-thaw process can be clearly and 4.0 cm.seen in the displacement curve of foundation F64. Thawing at the depth of freezing below theunder a pressure of 0.3 MPa (Figure 3) set at the footing initiates foundation settlement. . The faundepthof 1.0 m and marks located at different dation settlement stops a month later after thedepths close to foundation. Four stages can be soil is completely thawed and the temperature risesestablished:to +3-5"C. The additional foundation settlement1. No foundation heave takes place when the was 5.1 cm, the value of marks settlement was equalsoil is frozen to a depth of 1.4 m (40 cm below to the value of their heaving and no had additionalthe foundation footing) and the temperature at the settlements.bottom of the footing is -2'C. In such a case the Examination of displacement stages of the loadedrise of the mark at the level of foundation foot- foundations made it possible to note some featuresing is 3 cm, and at the level of soil surface 10 is in the nature of deformations observed in all thecm .experiments. For instance, under increased pres-2. Foundation heaving occurs during freezing sure the first stage becomes longer, at the secondfrom a depth of 1.4 m down to 1.75 m, with the stage the heave intensity becomes slower, and attemperature at the footing being -5'C. For this the third and fourth stages settlements increase.period the foundation heaving reached 3.2 cm, mark All the loaded foundations in the last stage had-7.8 and 15.8 cm.additional settlement, which was greater for more3. Foundation heaving comes to an end, while heavily loaded and less deep foundations, but itfoundation settlement and heaving of marks is still was especially characteristic of foundations withgoing on. The soil temperature at the depth of 0.3 ?.'&'a pressure on the foundation bed (Figure 3).freezing levels off. The foundation settlement With decreased pressure and increased depth of

262FIGURF, 4 Deformation of the soil samples under repeated freezing-thawingconditions.1,2,3,4,5 - soil samplesheaving ; thawing settlement-"" -- "Table 1Granulomerric composition of particle, % Void Plastic Liquid LiquidityTYPf! Ratio Limit Limit IndexNo. of soil 0.25-0.10 0.10-0.05 0.05-0.01 0.01-0.005 C0.005 (e) (W,) (WL) (IL)1 Loam 5.6 36.5 45.9 3.7 8.3 0.86 0.15 0.25 0.552 Loam 50,9 15.6 8.5 12.2 12.8 0.61 0.12 0.22 1 .oo3 Lo am 28.2 10.2 40.1 10.0 11.5 0.57 0.18 0.28 0.004 Clay 4.9 11.2 36.8 43.9 3.9 0.89 0.13 0.37 0.855 Clayey - - - +100.0 1.94 0.41 0.86 0.66fracturefoundation, additional settlements decrease and,To estimate the influence of repeated freezingin the case of unloaded foundations, were nor and thawing on the deformation acd on the bearingobserved. capacity of loaded foundation beds of clayey soil,Soft soils under positive pressure during the laboratory tests have been carried out: (blyshev,first year of freezing and thawing give only 1969; Fursov, 1979).settlement, The four years of observations show In consolidometers made of organic glass, nethat for the first winter season, additional samples with different types of soil, density, andsettlements are greatest and they subsequently moisture were compressed under pressures of 0.1-decay as the freeze-thaw cycle is repeated. 0.3 "a, until absolute stabilization was achieved.Additional compression of clayey soils under the Then they were frozen and thawed under the sameinfluence of freezing and thawing was caused by the loading. In some of the samples after a seriescomplex influences acting inside the soil forces, of freeze-thaw cycles the loading was reduced orcausing dislocation of mineral particles and film totally removed. While examining water-saturatedwater, formation of cryogenic textures, decrease of soils there was water in the lower porous disk ofsoil-bearing capacity and increase of deformation the apparatus. In examining the soils not satuabilityin thawing out. rated with water the was covered upper with disk

263paraffin to protect the soil from drying. Freezingwas carried out €or 40 hours at temperatures from-5'C to -20°C, and thawing took place at +18'C.The cycles were repeated from 6 to 30 times.The tests, given in Figure 4 and Table 1 fortypical types of soils yielded the followingresults. Clayey soils were compressed to a considerablygreater extent by cyclic freezing and thawingunder loading than without freezing. The mostintensive compression developed during the firstcycles. As the compression increased and thefreeze-thaw cycles were repeated, soil deformationdecreased, and the frost heaving and settlementduring thawing levelled out. The ultimate densitydepended on the loading, the degree of moisture,and the type of soil. In the clayey, water-saturatedsoil with the prevalence of clayey and dustyparticles, 0.2-0.3 MPa pressure density correspondedto the equation:e =!.@E Swhere e =wp =Gs =s=void ratioplastic limit, %specific gravity of solidssaturation, %The ultimate loam density depended on the loadingand optimal compressibility of the sandy and largedusty particles constituting them. Unloading aftercompression and the repetition of freeze-thawcycles increased heaving and decreased density.Analysis of the results of tests on differenttypes of soils under repeated freezing and thawingconditions provides approximate deformation dependanciesof loaded foundation beds on the physicalcharacteristics of the soil.Experiments on resistance to the shift of loamsand sandy loams before freezing and immediatelyafter thawing, run in the regime of the quickunconsolidated-undrainaged shift, showed the decreaseof their soil-bearing capacity. Figuresof soil-bearing capacity of dusty loams of nativestructure (e=0.7-0.9; Ip = 0.1-0.14; IL = 0.1-0.8) were reduced from 10 to 80%,of sandy loamsto 10%. The increase of density and sandy particlescontent, the consistency and the degree ofmoisture reduction ends in the decrease of freezingand thawing influence on the soil-bearingcapacity.The results of the investigation allow the depthof foundation footing to be chosen based on thefoundation bed calculations according to ultimatestates.REFERENCESFursov, V. V., 1979, Issledovanije vlijanija promorazhivanijai ottaivanija gruntov na ikhfiziko-mekhanicheskije svojistva.- IssledovanijaPO stroitel'nym konstruktsijam i fundamentam.Izdatel'stvo Tomskogo universiteta, Tomsk,p. 214-217.Karlov, V. D., 1979, Frost heave of unsaturatedloamy soil under field conditions. EngineeringGeology, vol. 13, no. 1-4, p. 41-52.Kiselev, M. F., 1971, Meroprijatija protiv deformatsijizdaniji i sooruzheniji ot dejstvijamoroznogo vypuchivanija fundamentov. MOSCOW,Strojiizdar, p. 47-54.Malyshev, M. A., 1969, Deformatsija glinistykhgruntov pri promerzanii i ottaivanii.- Inzhenernajageologija, osnovanija i fundamenty.Sbornik nauchnykh Crudov Tomskogo inzhenernostroitel'nogoinstituta, Tom XIY, Tomsk, p.58-62.Malyshev, M. A. and Fursov, V. V., 1982, Vlijanijesezonnogo promerzanija i ottaivanija glinistykhgruntov na rabotu osnovaniji i fundamentov.-Osnovanija, fundamenty i mekhanika gruntov, no.3, p. 16-18.Shvets, V. B. and Mel'nikov, B. N., 1969, Ustoichivost'melkozaglublennykh fundamentov v uslovijakhglubokogo sezonnogo promerzanija.- Osnovanija,fundamenty i mekhanika gruntov, no. 2, p. 13-18.

ARTIFICIAL ICE MASSES IN ARCTIC SEASP. I. Melnikov, K. F. Voitkovsky, R. M. Kamensky, and I. P. KonstantinovPermafrost Institute, Siberian BranchAcademy of Sciences, Yakutsk, USSRNatural climatic conditions in the arctic seas create preconditions for extensive useof ice and frozen ground as construction materials for creating artificial islands andstructural foundations in areas of shelf. Experiments were carried out off the KayaSea coast into the formation of ice masses both by freezing layers of sea water and bysprinkling. The rate of ice formation by means of repeated flooding was up to 12 cmdaily. The rate of ice formation by the sprinkling method was 0.7 about cm per hourat an air temperature of -15"C, and 1.1 cm per hour at -30°C. In the laboratory, therate of freezing of layers of water -2O'C at was from 0.2 to 0.55 cm per hour dependingon the wind velocity. Ice formed by the sprinkling method was more porous andsaline than ice formed by the freezing of layers of water or with natural sea ice,and its compressive strength was only half that of natural sea ice.The Arctic Sea shelf near the coast of the water has not yet been demonstrated. In thisSoviet Union occupies more than a million square connection it became necessary to study layered ickilometres and is rich in various mineral andfreezing from sea water.natural resources (Slevich 1977), particularlyoil and gas.Construction of artificial islands and founda-Experiments on layered freezing of water wereconducted early in 1981 during the construction ofa temporary experimental ice island in the Kara Setions for oil and gas prospecting and extraction (Voltkovskiy and Kamenskiy 198l). At a distanceis one of the most important problems related tothe development of the shelf. The movement ofof 300 m from the coast, the snow was removed froma natural ice site 50 m in diameter. The water wasthick ice in the arctic seas precludes the use of pumped on to the ice's surface by means of antraditional elevated marine platforms and otherartificial structural foundations.Conditions on the Arctic shelf require specificengine-driven pump, the water layer being about50 mm deep. After this layer froze and cooled down,water was poured successively and ice layers fromdesigns and means of constructing artificial bases 15 to 60 rmn thick were produced. At the same time,that take into account climatic and ice conditions. observations were carried out aimed at studying thThe Arctic shelf is known to have negative meanannual air temperatures and permafrost along thecoast, as well as a thick (1-2 m) ice cover thatexists for more than nine months of the year.Considerable movement of the ice cover occurs inmost regions. The action of winds and tides,together with temperature fluctuations, cause icehummocking. As a result of ice movement andhummocking, the ice cover exerts considerablepressure on artificial structures and islands.Natural and climatic conditions of the arcticseas create preconditions for the wide use of iceand frozen ground as building materials for theconstruction of artificial islands in the shelf'sshallow waters. Solution of the given problemrequires the following measures: Control of iceproduction and ground freezing; the rational useof ice and frozen ground in engineering; and ef-process of ice production, air and ice temperatureregimes, and the structure and physical-mechanicalproperties o f artificial ice.It was found rhar monolithic ice formed underconditions in which the next layer was frozen onlyafter cooling the previously produced ice layerdown ro -10°C. If this condition was not met,caverns with unfrozen brine remained in the bodythe ice.During the ice massif production abnormally highair temperatures and two long-term warnings occurred,Frequent strong winds and snowstorms presenteddifficulties for the production of ice in layersand sometimes the rate of ice-formation was sloweddown due to snow accumulationthe surface. Thehighest rate of ice production 12 was cm daily atan air temperature of less than -20°C. The dailymean ice production rate with consideration offective prevention of ice massifs and thawing of unfavourable weather conditions was 5 cm.frozen ground.By the end of the tests on layered ice produc-The Soviet Union has had experience in con-tion from sea water, the total thickness of the icestructing artificial ice massifs from fresh water massif was 4 m. It was submerged to sea bottom andand in using ice asbuilding material (Bubyr rose 1.2-2.0 m above the surface of the water.1965, Krylov 1951, Schelokov 1982). Investiga- There were no measures to protect the ice massiftions have been carried out to study ice-from solar radiation and sea waves. Systematicproduction processes and to determine ways toobservations of the ice massif's temperature regimeamplify them (Gordeichik and Sosnovskiy 1981, and melting were carried out prior to the onset ofGordeichik et al. 1980, Sosnovskiy 1982). Theice movement. After the surrounding ice cover hadconstruction of artificial ice massifs from sea been destroyed and the ice had been carried out264

265into the open sea, melting of the ice's surface andsides intensified. By the end of July, due to thedecrease in the ice massif's thickness, it came tolayered ice production, taking into account coolingdown to -lO'C, increases substantially when the airthe water surface and broke up during a storm. temperature decreases to -2OOC. Lowering the airStudies of layered ice production from sea water temperature further does relatively little tounder laboratory conditions were Undertaken, in increase the ice production rate. The effect proadditionto in-situ ice production. To do this, a duced by the wind velocity is more obvious. Withwind tunnel was designed in the underground refrig- an increase of wind velocity 1 from to 5 m/sec,erating chamber of the Permafrost Institute of the the rate of ice production increased 1.3-1.4 timesSiberian Branch of the USSR Academy of Sciences. and twice as much at a wind velocity of 15 m/sec.Inside the wind tunnel there was a special 3 0 8x4 ~cm thermoinsulated pan, equipped with sensors for TABLE 1. Duration (hr) of production and coolingmeasuring water and ice temperature. The airof sea water ice to a temperature -1O'C of (thicktemperaturewas constant during all the tests in ness of water layer is 25 mm)the chamber, the temperature ranging from -12 to-30°C. The air speed in the tube above the panwas held at from 1 to 15 m/s.AirWind speed h/s)The pan was filled with sea water0°C and temperatureplaced in the working part of the wind tunnel,("C) 1 2 5 10 15then the ventilation system was switched on. Readingsof the temperature sensors indicated the time -12 14.5 13.8 11.1 8.3 6.5for water freezing and ice cooling to down the-14 12.7 11.8 9.8 7.4 5.7control temperature of -10'~.-16 11.8 11.2 9.1 6.8 5.3The thickness of the layer of frozen water in -18 11.2 10.3 8.3 6.2 4.9the pan was recorded from 5 to 40 mm. To deter--20 10.7 9.8 7.9 6.0 4.6mine the relationship between the rate of ice-25 9.8 9.0 7.3 5.5 4.2production and the air temperature and wind velocity,-30 9.1 8.4 6.8 5.1 4.0a series of tests related to freezing a 25 mm layerof water were undertaken (Table 1). In addition,experiments have been carried out on freezing waterlayers of different thicknesses at constant temperatureand wind speed. On the basis of thesetests, it was found that the time t6 required for agiven water layer to freeze and for the ice to cooldown to -1OOC is in approximate linear dependenceon this layer thickness 6 (within 5 and 30 nnn) andcan be expressed by the empirical formula6t6 = t25Figure 1. As indicated in the plot, the rare ofwhere 6 is the thickness of the freezing waterlayer in mm, t25 is the time required to freeze awater layer 25 mm thick and to cool it down to-10°C.The time it took to freeze a water 40 layer mmthick was t6 = 1,7 t25. This means that by freez-0 -to -20 -30'cing a water layer with a thickness greater than30 mm, the linear dependence changes towards theFIGURE 1. The water layer freezing rate (J) vsair temperature and wind speed (V).increase of freezing rime, when compared to theabove-mentioned formula. When the layer of freezingwater is thin, the rate of layered ice productiondemonstrates negligible dependence on thethickness of the freezing water layers if do theynot exceed 30 m. This can be explained by theThe strength of the layered ice depends to agreat extent on its salt content. To define thisdependence more accurately a series of ice stresstests were conducted. Ice samples 73 mm in diameterand 130 mm high were produced by freezing layers offact that the intensity of the heat emanating from water having a given salinity. For this purposethe surface of the freezing layer by means of tur- sea water was diluted with fresh water, The testsbulent heat exchange as the next water layer begins were carried out at four temperature points, Theto freeze is presumably determined by temperatureand wind velocity; only when the ice thickness exceeds30 nun does the reduction of the intensity ofrate of load application in all the trials wasequal to 2 MPa/min. The results of these experimentsare presented in Table 2.the heat being given off become pronounced as well A pronounced increase in the ultimate strengthas usual decrease in water freezing rate when ice of the ice is observed at an ice temperature ofthickness increases.-4.5'C, as its salinity decreases. This dependenceFrom the aforementioned considerations, theactual rate of layer-wise production process canbe estimated based on the test results of freezingbecomes more complicated at lower temperatures. Aslight increase in ice salinity resultsin increasedstrength as compared to ice produced from fresh25 mm thick layers of sea water (Table 1). The water, whereas further increaseice salinitydependence of the rate of production upon the air leads to decreased strength. In all cases thetemperature at different wind speeds is shown in strength of ice increased as the temperature was

266TABLE 2 Maximum resistance of ice produced in TABLE 4 Physical characteristics of icelayers to uniaxial compression (ma)Density Porosity SalinityKind of ice (g/cm3) (X) (O/OO)Ice Strength of ice at temperature("C)salinityNatural sea ice 0.90 3.54.5(OIOO) -4.5 -7.0 -14.6 -27.5Manufactured ice,produced inlayers 0.87 5.79.9302217.49.200.8 1.2 2.5 6.31.1 1.6 3.4 7.41.5 2.6 4.1 7.5 Manufactured ice,2.4 3.3 4.8 7.6 produced by2.6 2.9 3.7 5.0 showering 0.84 9.016.5TABLE 3Ice production of sea water by the shower methodPre-experimentaltemp Thickness Intensity Time to coolAvg. air of ice Wind Shower of produced of ice ice layertemp. surface velocity duration ice layer production to -looc( "C) ( "C) (m) (hr) (cm) (cm/hr) (hr)-18 -16.5 12 2.9 6.0 2.1 5.4-18 -12.4 I1 2.4 6.0 2.5 -21 -19.4 0 2.0 5.0 2.5 --23 -21.4 1 2.25 3.0 1.3 --19 -18.2 3 4.25 2.0 0.5 0.5lowered. However, the higher the salinity, theThe temperature of the underlying ice increasedgreater its relative strength.during ice production by the shower method. ThisThe rate of layered ice production from sea indicates that to create a monolithic ice mass itwater is relatively low, and this limits the thir-k- is necessary to limit the shower time and to inteness of the ice massif created in the course of rupt the process periodically, so that the new iceone winter. It is known that the rate of icelayer can cool. The higher the intensity ofproduction when the shower method is used to build sprinkling and the thicker the manufactured layerice masses is faster than layered ice method by a of ice, the longer the required cooling rime.factor of four (Krylov 1951). By spraying seaBased on experiments and theoretical calculationswater, during which its drops are partially frozen it was found that the optimum thickness a single ofin the air prior to their contact with the surface ice layer ranges from 5 to 40 m. In field conofthe ice mass, the process of ice formation canbe accelerated to a great extent.ditions at weak wind the actual of rate sea waterice production (J) by the shower method attains,Experimental ice production from sea water using depending on the air temperature (ta), the followtheshower method was carried out in December 1981 ing values :in the same area where the experiments on layeredice production had been conducted. Five series of at ta = -15°C J = 0.7 cm/hrexperiments were carried out (Table 3) in which theta = -20acJ = 0.9 cm/hrwater expenditure varied from 2.5 to 9.5 R/sec atta = -25°CJ = 1.0 cm/hrspurt rotation speed ranging from 0.35 to 2.4ta = -3OOCJ = 1.1 cm/hrrevolutions per minute. When there was no wind,the radius of watering ranged from 23 to 35 m.The amount of ice produced can be somewhat in-The rate of shower intensity varied from 0.15 to creased when there is wind, a although in this case0.29 m/min. The rate of ice production depended it is difficult to ensure uniform ice production.on the pre-sprinkling air temperature, the wind It is possible to increase the rate by decreasingvelocity and temperature of the ice surface. The the size of the drops and by increasing the coolrotation speed of the stream of water and shower ing and partial freezing time. This can be broughtintensity had considerable impact on the rate ofice production. The intensity of ice productionincreases initially as the amount of water beingabout by raising the position of the stream ofwater and by expanding the dispersion area. Itcan also lead, however, to a substantial increasepoured on the ice surface is increased but then the in the porosity and salinity of the ice beingrate of ice formation decreases. The density of produced.the ice manufactured by the shower method was less To compare the mechanical properties of the icethan that of the layered ice production (Table 4). obtained by both the shower and layered methodsThis ice was also characterized by its high content with those of natural ice, impression resistanceof salts and spherical air blobs; it is a finegrainedice having chaotic structure.tests using a ball punch were conductedcorrespondingsamples of ice. Changes in the resistance

267I I 1 I I0 20 40 60 8OhFIGURE 2. Strength of ice (U, Mea) to ball stamppress in. 1 - ice, manufactured by sprinkling;ice temperature Bi = 6.4'C; 2 - the same ice, Bi=-11.8'C; 3 - ice, produced layer-by-layer, Bi =-6.4'C; 4 - the same ice, Bi = -11.8'C; 5 - naturalsea ice, Bi = -11.8'C.of ice to the pressure exerted on it by a 20 mmdiameter punch having a 4.65 kg applied loadweight are presented in Fipure 2.Strength of the ice produced by the showermethod turned out to be about half that of naturalsea ice and 1.6-1.7 times less than that of layeredice. The relatively LOW strength of the iceobtained by the sprinkling method is due to higherporosity and salinity of the ice.Because of the higher porosity and salinity ofthe manufactured ice, especially at temperatureshigher than -7OC, its strength is less than that ofnatural sea ice. Partial removal of brines duringice production could be a means of increasing icestrength. As sea water freezes, ice crystals withlow saline content begin to form. While thecrystals grow and their temperature decreases, theinter-crystal pores become smaller, the salts arepartially captured by the growing crystals, andconcentration of brine in the pores increases. Thepore brines are able to filtrate through ice. ThisWhen construc ting artificial ases b in the arcticseas it

APPLICATION OF MICROWAVE ENERGY FOR ACCELERATINGEXCAVATION IN FROZEN SOILYu. M. Misnyckt 0, E. Shonin,' N. I. Ryabetsq and V. S. Petrov2'Leningrad Mining Institute, Leningrad, USSR'North Mining Engineering Institute, Siberian BranchAcademy of Sciences, Yakutsk, USSRThe paper examines the heating of frozen ground by means of microwave energy inorder to determine the most rational thawing regimes where frozen masses are beingprepared for excavation by formation of local thawed zones or by thawing of a slopein layers. The derived equation of the advance of the thawing front created by theabsorption of microwave energy by the rocks as well as experimental data revealedthat the main critical parameters for thawing frozen rocks by microwave energy arethe depth of penetration of the electromagnetic field, the area of of formation athawed zone at the surface through which the electro- and thermo-physical propertiesof the rock exerr an influence on the thawing, and the frequency and strength ofthe microwave energy flow. It was shown that when operating under optimal conditions,typical depths of microwave thawing, dependlng on the frequency and type ofrock, are 0.1-0.6 m with a COnsmptiQn of microwave energy of 20-30 kWh/m3.INTRODUCTIONeffective. Examples are mining deep gravels,geological exploration, driving of prospect pits,Unconsolidated frozen soils, particularly those opening of damaged zones of underground networks,containing coarse grained materials, are very dif- etc.ficult to disintegrate because of their great In all of the cases in which microwave techstrengthand abrasiveness. Therefore in most cases, nology is to be used one must consider the optimumthe excavation of frozen soil can be achieved only values of such characteristics as the depth of theafter their strength has been reduced. One method thawed zone, the time of electromagnetic action andof preparing massive permafrost for excavation is the energy efficiency. This paper addresses theby thawing. Traditional heating, however, is not results of experimental and theoretical study ofsufficient for this purpose: it is time-consuming these characteristics.due to low frozen soil heat conductivity and hasnegative effects caused by the heaters on thethermal regime of the excavation site. ThisTHEORETICAL DEFINITION OF THE PATTERNSexplains the interest in the use of microwaves asOF PHASE FRONT MOVEMENTan efficient thawing method. Such energy treatmentof materials is already widely used in numerous Figure 1 shows a microwave device for thawingfields of science and technology for the enhance- frozen soil consisting of a generator operating atment of various processes.one of the frequencies (2375, 915, 430 MHz) desig-The use of microwave energy in new the area of nated for commercial application, a feeder, and apermafrost thawing is based on the followingmicrowave irradiator which distributes the heatfeatures of the electromagnetic field interaction required in a stope. The mass permafrost to bewith frozen soils (Misnyck 1982):excavated is prepared by forming local thawed zones- inner massive heating due to the direct trans- in the mass in the form of thawed strips or byformation of microwave energy into heat as a result layered thawing of the entire stope.of its absorption during polarization of the frozen Without going into the details of any particulasoil in the electromagnetic field;type of microwave irradiator, we shall examine the- the limited impact of heat conductivitythe heating of a permafrost mass where a plane electromagneticwave strikes the surface in a normalformation of a temperature field, as compared tothe action of internal heat sources caused by the fashion and where the energy's flux density Sabsorption of electromagnetic energy;depends only on coordinate 2, counted at mass- technologically acceptable, microwave depend- interior from its surface. This approximation isant, thawing depths of 0.1-0.6 m attained in the assumed because the absorption of electromagneticcourse of several minutes of microwave action, energy takes place in the near-irradiator regiondepending on frequency and flux density;in which the energy has not yet dissipated.- capability of highly efficient, non-contact Since we are interested primarily in phase fronttransmission of microwave energy into the soil; movements, and to a lesser degree in temperatureThese features together with the capacity for distribution, we may limit the examination ofstructural and electromagnetic compatibility of Stephan's problem to the derivation of a rule formicrowave technology with existing mining equipment phase front movement based on the following considindicatecases where microwave energy would be erations.268

2690 fa the depth of electromagnetic field penetrationdetermined from relationship E(O)/E(h) = e, whereE is electrical field intensityh = xovT/lT E" (2)Experiments show that much less time is requiredfor permafrost thawing by microwaves than by heatconductivity. Therefore we can ignore heat conductivityand derive the phase front movementequation assuming evident condition-energy absorbedat given point Z by the time t of phase frontapproach to this point to be equal Q = cvlT; I t q ,where +, Ti, and qp are respectively heat capaciryper unit volume, inltial temperature, and phasetransition energy per unit volume. This bringsabout the following equation (Nekrasov and Rickenglass1973).t~[exp(2d/hf) - 11 = 1 N(d) dt (3)Twhere T is the time of surface layer thawingFIGURE 1 Diagram of microwave device for frozen After integro-differential transformations and asoil thawing.number of algebraic manipulations the desiredfunction d(t) can be found as (Rickenglass andElectrical properties of frozen and thawed soils Shonin 1980).differ enough to represent temperature-dependentchanges of complex permittivity f = E' - i&" bystep function T=O, at averaging the value of€ d = O.5ht&n[l+B(t/-r- I)] (5)separately for temperature zones above and belowzero. Typical values of the dielectric constantE' and the dielectric loss factor&", based on 2375where B = hf/ht. This expression helps to deter-KHz frequency measurements (Shonin and Sokolovamine the speclfic microwave energy consumption as1981), are Ef = (3-71, &; = (0,1-3) and E[ = (10-a transmitted energy flux density per depth of251, &; = (2-71, depending on soil type. Subthawedzonescripts f and t refer to frozen and thawed statesof soil, respectively.W(t) - St/0.5htRn [I + i3(t/T- I)] (6)If a step approximation of &(T) is adopted,frozen soil occupying a half-space Z 2 0, may beconsidered in electromagnetic terms as a layeredlossy dielectric medium, in which the boundarybetween electrically contrasted media coincideswith a moving phase front.As the period of oscillations is obviously muchsmaller than the time needed for thawed layer depthd to change markedly, the electromagnetic fielddistribution in the ground may be defined assumingthe value of d to be constant. These assumptionsallow solution of the intensity of heat sources perunit of volume q = -div S, where S is power fluxdensity at observed point in frozen ground, usingwell known one-dimensional wave equation solutionfor stratified medium. Omitting intermediatetransformations, we petq(z) = 2So/hf * N(d) exp (-2dhf). d z 500 (1)where So is incident energy flux density, N(d) ispenetration coefficient, taking into account theenergy reflected from ground surface and energyabsorbed in thawed layer. This coefficient is acomplicated function of thawed layer depth d,complex permittivities Ef and Et, and wave lengthx,. Note, that N(0) 2 e / (i + @) and N(d+m)=Analysis of equation (6) allows examination ofmicrowave thawing with minimal energy consumption.If S is given, the parameters of such a regime maybe derived from condition aw/at = 0, which resultsin the following equationNext, the value of d is easily defined from (51,whereoptt = topt.The expressions derived above show that introducingsuch characteristics of thawing as T h andis better considered as space and time scales ofthe process studied, respectively. This dramaticallysimplifies digesting phase front movementhistories, and facilitates understanding the wayin which microwave parameters S, and X, (just aspermafrost electrical and thermal properties),depending in turn on soil types, moisture content,soil density, soil grain size etc., influencepermafrost thawing.The developed theoretical model of permafrostheating promoted further experimental investigationof frozen soil thawing under microwave action.

270EXPERIMENTAL DETERMINATION OF MICROWAVEPARAMETERS FOR THAWING FROZEN SOILThe initial experiments aimed at study of thawedzone formation depths employed blocks of artificiallyfrozen sand-clay, placed in a refrigerator 100chamber at temperatures of -1O'C and -3O'C. Therewere two soil types under study: sand-loam (moisturecontent w = lo%, soil density = 1.55 g/cmS,initial temperature Ti = -3OOC) and sand (W = 52,80y = 1.4 g/cm3, Ti = -10°C and -30°C).The radiator utilized had flanges, open ends, arectangular waveguide with a cross sectional area @of 9x4.5 cm2 and equipped with a dielectricquarter wave length plug. The waveguide output wascontrolled by means of a dissipative adjustable 40attenuator, while the power radiated was indicatedby thermistors, installed in the ports of abidirectional coupler. Power flow densityradiated was 110, 40 and 16 W/em2 at 2375 MHz20frequency. Frozen soil block dimensions werechosen (0.3~ 0.3~ 0.4 m3) to simulate a semiinfinitedielectric half space so far as propagationof electromagnetic waves was concerned.The time of surface layer thawing was determined0 2 4 6 0 e/8, #/anas a time when surface temperature of the block at-FIGURE 2 Influence of microwave energy flux dentainedzero. Thawed zone depth was measured alongthe waveguide axis where energy flow density wassity S and energy of phase transition Q on the timeT of surface layer thawing.maximum and equal to 2P/o, where P is power transmittedinto the irozen soil block and 0 is thecross sectional area of waveguide.When experimental verification of the theory wassought, analysis of the T vs Q/S experimental datad,omlinear function approximation, as seen from Figure2, proved to be valid. It should be noted thatproportionality constants of both lines appearedto be equal to hf, as was predicted by expression(4).The relation between the depth of d thawed zone,8obtained for different values of power flux densityS, and normalized time of microwave action t/'l isshown in Figure 3. Inspection of the plotted dataindicates that, if the normalized variable t/r is6used, the influence of S on d in this case vanishes.This makes the experimental data approximately thesame as the theoretical curve (5). Comparison oftheory and experiment revealed some scatter in thedata of d vs t/T when = hf 19.5 cm and h = 6.4 cm.4Thus, the results justify the theoretica! model ofmicrowave heating of frozen soils developed above.In spite of a number of assumptions, this modelrepresents microwave thawing histories correctly 2and may be recomnended for approximate calculationsof the process parameters.The investigations of microwave thawing of permafrostemployed experimental microwave devices at2375 MHz and 915 MHz frequencies, providing an0energy flux density at the i radiator center of4 10 and 23 a lo4 W/m2 respectively. In theformer case, a pyramidal horn with cross sectional FIGURE 3 Dependence of thawed zone depth on darea of aperture 0 = 0.,75 x 0.38 m2 was used,normalized time t1-i of microwave action.while in the latter E-sectorial horn with a = 0.5x 0.22 m2 was chosen.Yakutsk region (Ti = -7"C, w = 12-14%, y = 1.6There were two soil types covered. The first tn/m3 , C, = 1.2 MJ/m3 - "C) .one heated at 2375 MHz was coarse-grained soil-Figure 4 illustrating the dynamics of permafrostpebbles cemented by clay 50-60% filling (.Ti =thawing shows that both curves change most rapidly-6OC, w = 9-IO%, y - 1.9 tn/m3, C, = 0.7-0.8from T (40s - curve 1 and 50s - curve 2) until t =M..T/m3 * "C) and the second one heated 915 at MHz (4-5)~. During microwave action the depth of thewas represented by the sand of active layer inthawed zone reaches 0.28-0.32 m at 915 MHz and

20 100 200 300 t,sFIGURE 4 Dynamics of permafrost thawing by microwavesat 915 MHz (curve 1, sand) and 2375 MHz(curve 2, coarse grained soil).0.07-0.08 m at 2375 MHz. Further microwavetreatment of the massive permafrost slows down therate of phase front movement. This is caused byattenuation of the electromagnetic wave propagatingthrough the thawed layer.Figure 5 indicates that during thawing, microwaveenergy consumption per unit of volume W changesso that the curves W(t) have minimums. This factis of practical interest because it promotes thawingwith maximum productivity. The experimentalhata indicate that such a regime for heating frozensand at 915 MHz is realized when dOpt = 0.27-0.28m, Stopt .= (2.5-2.8) * lo4 kJ/d and W = lo5 kJ/m3or 30 Wh/r3.If inner heat sources are distributed uniformlyin the ground, the energy consumption for its thawingis 0.75 * lo5 kJ/m3. Comparing this value tothat obtained above, we see that the coefficient ofmicrowave power utilization is rather high andequal to 75%.Similar parameters of coarse grained soil thawingat 2375 MHz may be defined as dopt = 0.06-0.07m, Stopt = (0.5-0.55) - lo4 kJ/m2 and W = 0.7 * lo5?dim3 or 20 kWh/m3.The energy consumption listed above was determinedtaking into account radiated microwave poweronly. If the generation losses of 30-40% areconsidered the actual value of this parameterincreases 1.4-1.7 times.The curves of Figure 5 indicate that microwaveenergy consumption decreases when moisture contentor, what amounts to the same thing, phase transitionenergy diminishes. That is why it is especiallypromising to use microwave thawing of permafrostin coarse grained frozen soils.FIGURE 5 Variations in microwave power consumptionW with time of electromagnetic action: 1-sand,heated at 915 MHz, 2- coarse grained soil, heatedat 2375 PMz.According to equations (2) and (5) as well asexperimental data (Figure 41, the depth of thawingincreases when frequency decreases. Therefore, theestimation of parameters of thawing at 430 KHz isespecially interesting. New values of d, may bedefined based upon experimental data dl and d2obtained at 2375 and 915 MHz respectively, if theelectrical properties of soils are assumed to befrequency independent, and it is required thatt/T be constant at every frequency covered. Usingexpressions (21, (41, and (5) this producesd, = anXm/Xn, t, = tn&s,/AnS, (8)where subscripts m, n = 1, 2, 3 refer to wavelengths12.6, 33, and 70 cm, which correspond tofrequencies 2375, 915 and 430 Mlz respectively.Formula (8) gives values of optimum depths ofthawing at 430 MHz as follows: 0.55-0.6 m forfrozen sand and 0.35-0.40 m for coarse-grainedsoil. The depth limits of thawing restricted byslowing down of phase front movement may be estimatedas 0.6-0.7 and 0.40-0.45 m respectively.Permafrost thawing to greater depths should beperformed layer-by-layer.Note that, to secure a permanent rate of thawingindependent of frequencies used, the characteristicsof microwave power action should satisfy thefollowing condition XmSn/XnSm = const. Energyconsumption in this case, as it is seen fromequation (61, does not change.In conclusion, these results may serve as a basisfor the rational use of microwave energy in varioustechnical applications related to permafrost.

REFERENCESRickenglass, L. E., and Shonin, 0. B., 1980,Misnyck, Yu. I!., 1982, Philosophy of frozen soilApproximate calculation of the parameters offrozen soil thawing by microwaves: Technicalslackening by the action of microwave energy:Institute Transactions on Mining, v. 4, p. 43-Leningrad University Press.46.Nekrasov, L. B., Rockenglass, L. E., 1972, Elicro- Shonin, 0. B., and Sokolova, N. V., 1981, Superwave energy reflection from semi-infinite lossy high frequency dielectric properties of frozendielectric medium in presence phase transition soils: Physical Processes in Mining, v. 9,in it: Journal of Technical Physics, v. 7,p. 29-35.p. 1339-1342.

CRYOGEOTHERMAL PROBLEMS IN THE STUDY OF THE ARCTIC OCEANYa. V. Neizvestnov, V.A.Soloviev, and G.D. GinsburgAl 1-Uniorl Institute of Mineral Resources of the World OceanLeningrad, USSROne of the most notable geological-geophysical features of the Arctic Ocean is thepresence in any sea-bed section of a cryolithozone, involving frozen sediments andground ice. The stages of its evolution in shelf areas correspond to cyclic regressionsand transgressions in the Polar Arctic Basin. This involves an oscillationfrom unfrozen submarine sediments through a newly formed submarine frozen to a zonefrozen terrestrial zone, and then back through a relic submarine frozen zone to anunfrozen submarine zone. Sedimentation on the sea bed on the shelf is closely relatedto the evolution of the cryolithozone. Widespread occurrence of ice-rich lacustrinealluvialdeposits on the Arctic shelf in the Late Pleistocene is inferred on the basisof peculiarities of sedimentogenesis in the course of thermal abrasion of the sedimentsduring the transgressive phase of development of the Arctic Basin. Submarine lithogenesisis accompanied by unique changes in the fluid phase, viz., salinization ofpore water and the formation of gas hydrates. It is possible to outline possible gashydrate-bearing areas on the basis of cryogeothermal reconstructions. Submarinepermafrost also dictates a number of peculiarities in the geophysical fields, especiallythe mobility of the thermal fields; thisextremely critical in the case of formationand degradation of the frozen andlor gas hydrate-bearing strata.The cryolithozone is the most distinctive andcharacteristic geologic-geophysical feature of theArctic Ocean area. This paper deals mainly withcryogeothermal aspects related to paleo-geography,polar lithogenesis, and changes in the fluid phasemarine frozen zone. The first stage favored deepfreezing of much of the shelf, at the presentapproximately 110 m isobath. In the easternEurasian shelf, over a vast area adjacent to theNew Siberian Islands, off the southern Laptev Sea,of rocks and bottom sediments, in particular, gas and the southwestern East Siberian Sea, there washydrate formation, peculiarity of geophysical field a concurrent freezing sedimentation and the formaisdiscussed as well.A cryolithozone, submarine inclusive, may betion of thick syngenetic polygonal wedge ice. Thepresent subaqueous frozen rocks outside thedetermined as a part of the lithosyhere within the littoral zone are mainly relics of that time.negative temperature belt. Physically, it may be During the last transgression, which began 18-frozen (ice-bearing, in particular ice-bonded) and 19,000 yr B.P., the frozen zone was not completelyunfrozen (saturated by negative temperature salinewaters-cryopegs). To distinguish types of submardegradedand it fell within the subaqueous environment.This stage was marked by thermal abrasionine cryogeothermal environments it is reasonable to that resulted in the reworking of older rocks thattake into account a thermic field pattern, whichcan be stationary and nonstationary. The nonstationarystate is typical of the submarine frozencryolithozone (frozen zone, for short) both for theaggradation during the formation and the degrada-were different in genesis and age. The heavilyiced syngenetically frozen deposits from the UpperPleistocene were then thermally abraded for theentire thickness. Thermal abrasion was strongeston the eastern Eurasian Arctic (Are, 1980) andtion of relic frozen ground.Beaufort Sea shelves.Conditions favorable for deep freezing andThe above two stages of cryolithozone evolutionfrozen zone formation on land in the northern polar are based on numerous datings of the sea level inarea seem to have existed during the entire Late various tectonically stable regions of the worldCenozoic since the Eopleistocene. Within the ocean over the last 30,000 yr (Curray, 1961, andpresent shelf area, freezing could take place only others) including the Laptev Sea Shelf (Holmes andduring subaerial stages, though it may start even Creager, 1974). The average curve plotted usingunder subaqueous conditions when the water depth these data (Figure 1) is free of a tectonic condoesnot exceed the ice thickness. A transition stituent and hence reflects actual eustatic changesof the frozen zone, formed under subaerial condi- (the nature of which can be hydrocratic, particutions,into the subaqueous position is accompanied larly glacioeustatic and geocratic). The eustaticby abrasion and thermal abrasion of the frozen changes were a global factor that determined theground. Thus the evolution of the shelf cryolitho- cyclic development of the shelf cryolithozone. Inzone is subject both to subaerial and subaqueous certain cases the change of subaqueous and subconditionsand by the change of environments. aerial regimes is independent of eustatic changes,Two final stages-Late Pleistocene (pre-Holocene) though against their background. Local coastlineregressions and the last Late Pleistocene-Holocene displacements now taking place in some areas offtransgression-affected most of the present sub- the Arctic Ocean are mainly locally controlled and273

I27420m0h 6Cd-- repssion V=l.1 cm1yca.r90 is 10 is' ' io '5 0thousand yew BPFIGURE 1 Averaged curve of eustatic sea levelfluctuations during the past 30,000 years.a) changes in level; b) deviation from the mean;c) number of individual curves used; d) rate ofeustatic change in sea level.are due to recent tectonic and, in particular,glacioisosratic movements of the Earth's crust. Insuch cases regime changes are oscillatory in nature,like the eustatic sea-level changes.Thus, cyclic regressions and transgressions inthe northern Polar Basin during the Late Pleistocene-Holocenewere due to eustatic changes in theshelf cryolithozone of the World Ocean. During theregressive stage (28,000 to 18,500 B.P. for theArctic shelf as a whole), the cryolithozone successivelyevolved from a submarine unfrozen zonethrough a submarine newly frozen zone to a continentalfrozen zone. The transgressive stage (18,500B.P. to the present) shows the evolution of thecryolithozone from a continental frozen zonethrough a relic submarine frozen zone to a submarine unfrozen cryolithozone. A similar sequence maybe established for any particular region where thecoastline migration and related environmentalchanges were due to recent tectonic movements. Therelationship between a stage of cryolithozonedevelopment and transgressive-regressive cycles maybe used to describe both direct (extent of permafrostzone assessed using paleogeographic data) andinverse geocryology problems.The authors have solved one such problem. Anarea of probable lacusrro-alluvial Late Pleistocenedeposits with high ice content and thick syngeneticpolygonal wedge ice was mapped on the recent shelf(Figure 2). On land these deposits are known as"edoma"; they are comon on the maritime lowlandsof Yakutia and the New Siberian Islands. Suchdeposits with high ice content seem to be intenselythermally abraded during marine transgression. Ifa normal marine basin is defined by a stastisticalrelationship between its depth, the distance fromthe coast, and the particle size distribution ofthe bottom sediments (Richter, 1965), then in thiscase it does not exist. The reconstructions arebased on these assumptions (Soloviev, 1978).The coefficient of relative clay content yFIGURE 2 Position of LatePleistocene coastline on the Laptev and East Siberian shelves. Hatched arearepresents land area within which a complex of ice-rich deposits developed.

275CC-r///L///////////cI/II//fd?FIGURE 3 Some variants (1-111 as explained in the text) in the development of relict submarine permafrostdepending upon hydrodynamic conditions. 1 - sea water; 2 - unconsolidated deposits; 3 - vector ofsediment accumulation; 4 - vector of erosion; 5 - unfrozen sediments; 6 - boundar of the frozen zone.SI and S2 - salinities of sea water and pore water respectively (SI > S2); T$ and T$ - temperaturesof phase change in sea water and pore water respectively; X - thermal conductivity of deposits (X 4 X2).(Richter, 1965) was used as an index of the par- supported by the presence of numerous submarineticle size distribution of the bottom sediments. pingo-like-features (O’Connor, 1980) whose extentOn the Laptev and East Siberian Sea shelves more is confined to the region discussed.than 1200 determinations were made for y and HA Late Pleistocene paleoland recognized on the(water depth), resulting in two sets of data that Laptev, East Siberian, and Beaufort Sea shelvesare reliably geographically linked. One set of may be important to forecast the extent of a subdatais characterized by a statistically signifi- marine relic frozen zone. It is there that frozencant (at 0.05 significance level) y-to-H relation rock may occur; this is confirmed by drilling dataand is restricted to shelf areas where Late for offshore areas of the New Siberian Islands andPleistocene-Holocene transgression has not been the Beaufort Sea shelf. Recently vanished due tofollowed by some specific processes. There is no thermal abrasion, Semenov, Vasiliev, Diomid, andy-to-H relation at the same significance level for other islands (Gakkel, 1958; Grigorov, 1946) alsothe other set of data. In our opinion, this is due occupied the above areas of the East Arctic shelfto the fact that, at the final stage of transgres- of the USSR. Though it is quite improbable, somesion, intense thermal abrasion strongly affects thin relics of frozen rocks may occur within the"edema"-type deposits with high ice content (volu- area delimited by the 110-m isobath.metric ice content of 80-90%).The data available for the Beaufort (Sellman andA sequence about 40 m thick was reworked by Chamberlain, 19791, Laptev, and East Siberian Seathermal abrasion to form a section of Holoceneshelves suggest that there is no regular relationsedimentsseveral meters thick; they are nonuni- ship between the depth to the top of subaqueousformly distributed over the leveled sea floor. frozen rocks and the distance from the coast. TheMean values for the coefficient of relative clay development of a relic submarine frozen zone andcontent of these sediments and of Upper Pleistocene in particular the depth of occurrence seem to beice-containing deposits from the New Siberian controlled mainly by the hydrodynamic environment.Islands at the 0.01 significance level do not Figure 3 shows some evolutionary patterns of a subdiffer,supporting their comon genesis.marine frozen zone in shelf areas with negativeThe data for the sautheastern Beaufort Sea bottom temperature.obtained from 244 stations (Pelletier, 1975)When the thickness of a relic frozen zone isreveals two similar sets of data. The absence of determined by the mean annual bottom temperaturethe y-to-H relation shows, in particular, in a large and the sub-bottom geothermal gradient while bottomarea north of Tuktoyaktuk Peninsula, stretching sediment erosion is compensated for by sedimentawest-eastapproximately for 250 km and LOO kmtion, we have a situation that corresponds to asouth-north. It is considered a Pleistocene land quasi-stationary condition. In this case thawingthat was transformed into subaqueous state during from below ceases, but the upper of part a frozenthe Holocene transgression. This conclusion is sequence may deteriorate (thaw) for some depth

276owing to marine water salt diffusion. In such astate, neither temperature nor hydrodynamic conditionschange (Figure 3-1). The top of frozenrocks may lie just near the bottom, as in theDmitriy Laptev Strait and the Ebelyakh Bay (southeasternLaptev Sea) areas.On the shelf, where sedimentation is intense(Figure 3-11] a stratum saturated by saline wateris formed above a frozen zone. The negative temperaturearea shifts up the section with depositionand the frozen rocks thaw from below (Figure 3-IIb).This may well be the case for Gedenstrom Bay (NewSiberian Islands) where at a water depth 4 m of thetop of the frozen rock is exposed at a depth of 9to 24 m. The process discussed can result a incompleted degradation of the frozen zone and theformation of an unfrozen cryolithozone (Figure3-IIc), such as in the Sannikov Strait (NewSiberian Islands).Continuous erosion of the bottom underlain byfrozen rocks (Figure 3-111) can also occur. Whileits thickness remains constant, the top of thefrozen zone moves down the section (Figure 3-IIIb).If the thermal conductivity of the underlyingdeposits is higher than that of the original (over-lying) frozen rocks, then the thickness of thesubmarine frozen zone may increase (Figure 3-IIIc).This may occur in areas of present submarine up-FIGURE 4 Conditions for the existence of methanelifts at a water depth 100 of my which werehydrates at the bottom of the arctic seas. N =situated on land at the end of the Late Pleistocenesea depth; t = sea bed temperature.due to the eustatic drop in the sea level. Inareas of recent subsidence an intense Sedimentationand, under certain conditions, complete degradationof a submarine relic frozen zone may occur.The submarine cryolithogenesis is followed by a crystallized in freezing, being the most resistant,peculiar change of the fluid phase, both pore waters may be preserved in unfrozen rocks.and gases.The formation of gas-hydrate bearing rocks andThe evolution of pore water similar in composi- sediments holds a unique position in submarinetion to marine water starts on the seafloor bycryolithogenesis. It may be stated that theshallowing to a depth 2 of to 5 m when fast ice is process of gas hydrate formation in the earth'son the bottom most of the year and at temperatures interior along with PT-conditions is determined byon the freezing front below -1 or -2°C. Undersufficient amounts of gas and water, their composilagoonalconditions, freezing may begin with the tion and genesis, mineral composition, the structurepresence of a water layer under the ice. In this and texture of rocks and sediments, the presence ofcase, freezing increases marine water salinity to organic matter, and a mechanism that occurs when60-80 g/kg and more, and the temperature of freez- gas and water molecules are brought into contact.ing brine drops to -4 or -5OC.The influence of the above factors has not beenThe freezing of deposits saturated by salt water studied in detail, though it is quite evident thatis accompanied by the crystallization of ice and they impede gas hydrate formation in the rockscalcite. The average content of calcite in ice(Ginsburg, 1969).formed by freezing of normal marine water amounts To formulate a problem to assess the possibleto 0.09 g/kg (Gitterman,'1937). At a freezingexistence of gas hydrates in offshore arctic seastemperature lower than -7.8 to -8.2'C, mirabilite it is reasonable to use an equilibrium curve forbegins to crystallize. The content of mirabilite the methane + 3.5% sodium salt solution in PTinice under these conditions may reach 6.3 g/kg. coordinates. One should take into account that whenAt a freezing temperature below -23"C, hydrohalite true PT conditions comply with the field of methanecrystals are liberated from the liquid phase; their hydrate stability in the above system, hydratescontent in ice-cement may exceed 20-30 g/kg.might not exist at all.The water that saturates rocks is separated intosolid ice, ice left in the frozen zone, and freezingbrines. The total salt content of the brines atCalculations show that areas of probable methanehydrate stability in the Arctic are situated wherethe total thickness of the cryolithozone and theequilibrium with frozen rocks gradually changesfrom 35-40 g/kg at -2°C to 115 g/kg at -7.6'C, andreaches 230 g/kg at -22.5OC (Gitterman, 1937).seawater layer exceed 250-300 m (Figure 4). Eence,A composition of relic freezing brines min- anderals may be used to infer freezing paleotemperatures.For instance, at the transgressive stage ofthe Polar Basin development, when a frozen zonedegrades, the ice thaws, and the salts thar werein H,O*1 \'\45a discontinuous distribution of these areas may beinferred for the Arctic shelf.The cryolithozone (primarily the frozen zone)defines some peculiarities of the geophysicalfields of arctic offshore areas, i.e. abnormallyhigh velocity for small depths and abnormally lowvelocity for the electric conductivity of sub-

27 7bottom deposits; probable gravity anomalies related the authors have tried to show that these studiesto ice content; and the generation of natural are closely connected with those of the Lateelectric fields due to phase transitions at the Cenozoic paleogeography and the present thermalfrozen rocklsalt water interface.state of the Arctic Ocean. Most of the problemsThe similar physical properties of gas-hydrate have not yet been fully solved. Problems to bebearing and frozen deposits.result in unambiguous solved in the near future are: assessment of theinterpretation of geophysical data, In debatable extent of the submarine relic frozen zone on thecases, the absence of frozen ground at a water arctic shelf, mapping it, and determining to whatdepth of more than 100-110 m and of hydrate-bearing degree the sub-bottom deposit heat field is nondepositswhen the net sequence of the cryolithozone stationary in various parts of the Arctic Ocean,and water body are at less than 250-300 m are helpfulfor interpretation,The most important geophysical feature of theREFERENCESArctic Ocean is a clearcut instability of thethermal field. This is most evident in shelf areas Are, F. E., 1980, Thermal abrasion of shores:where a frozen zone is present. As noted above,Mooskva, Nauka (in Russian).the present 100-110 m isobath outlines areas where Curray. J. K., 1961, Late Quaternary sea level:a frozen zone was widely (almost ubiquitously) a discussion: Geological Society of America,developed during the Late Pleistocene. Feat flow Bulletin, 72, p. 1707-1712.measurements obtained for the bottom sediments in Gakkel, Ya. Ya., 1958, Distribution of Semenovskysuch regions cannot be used to describe geothermal Island, in Problemy Arktiki, vyp. 4: Leningrad,conditions at depth. In this case measurementsMorskoi Transport, p. 95-98 (in Russian).should be made in boreholes whose depths well Ginsburg, G . D., 1969, On the formation of crystal-exceed the maximum paleothickness of the frozenzone. The paleothickness may be within 500-111 arange depending on the water depth and the distancefrom the coast. Such specific recommendationscannot be given at the present state of knowledgehydrates of natural gases in the earth's interiors,Hydrogeologia Yeniseyskogo Severa:Leningrad, NIIGA, p. 109-128 (in Russian).Gitterman, K. E., 1937, Thermal analysis of marinewater, & Trudy solyanoi laboratorii AN SSSR,for the shelf areas beyond the 110 m isobath.vyp. 15, ch. I: Moskva, AN SSSR, p. 5-32 (inThe thermal non-stationarity of deep-sea rocks Russian)is inferred from the thermal structure of the water Grigorov, I. P., 1946, Vanishing islands: Priroda,body. It is characterized by negative-temperatureN 10, p. 65-68 (in Russian).bottom water (ocean cryopegs) separated from cold Holmes, M. L., and Creager, J. S., 1974, Holocenesurface water by a layer of relatively warm (posi- history of the taptev Sea continental shelf, &tive temperature inclusive) Atlantic waters. TheMarine geology and oceanography of the Arcticocean cryopegs are underlain by the unfrozen sub- seas: New York, Springer, p. 211-229.marine cryolithozone. There are two alternative Neizvestnov, Ya. V., Tolstichin, N. I., andviewpoints on the nature of the ocean bottomTomirdiaro, S. V., 1970, Negative temperaturecryopegs. This water body is considered to bewaters of the Earth, & Tezisy dokladov Vsesoy-either a relic of the glacial epoch (Neizvestnov, uznogo soveshchania PO merzlotovedeniyu 19701970) or a result of present-day shallow water goda: Moskva, MGU, p. 78-79 (in Russian).discharge. If the former case, the bottomwaters and underlying sediments are now beingO'Connor, A. D., 1980, Study of pingo-like-featuresdetected in Beaufort Sea: Sidney, B.C., Canada.warmed, and if the latter, they are being cooled. Pelletier, B. R., 1975, Sediment dispersal in theHence, the representativeness of heat flow measure- southern Beaufort sea, & Technical Report No.ments in Arctic Ocean bottom sediments is to be 25a: Victoria, B.C., Canada.judged with due regard for heat balance.Richter, V. G., 1965, Methods used in studies ofWhen deepwater heat flow measurements in theinner ocean area, including the continental slopes,neo- and recent tectonics of sea and ocean shelfzones: Moskva, Nedra (in Russian).are analyzed, one should take into account the Sellman, P. V., and Chamberlain, E. J., 1979, Permaoceanicgas-hydrate formation, i.e. the latent heat frost beneath the Beaufort Sea: near Prudhoe Bay,of a gas hydrate phase transition may become an Alaska, ifl Proceedings of the 11th Annual Offadditionaland important fact resultinga non-shore Technology Conference, Houston, Texas,stationary heat field. In addition, the thermalv. 3: Dallas, Texas, p. 1481-1494.conductivity of gas-hydrate bearing deposits differs Soloviev, V. A., 1978, Laptev and East Siberian Seafrom that of water-saturated sediments. Theshelves in Late Pleistocene (Mapping techniquepossible presence of gas hydrates should be taken of Late Pleistocene coastal line), & Theoretintoconsideration, however, not only in studiesof the Arctic Ocean but of the other oceans as well.The cryogeothermal study of the Arctic Ocean isicheskie i methodologicheskie osnovy kompleksnogoizuchenia i osvoenia shelfov: Leningrad,VGO SSSR, p. 127-129 (in Russian).a separate scientific problem. At the same time,

INVESTIGATIONS INTO THE: COMPACTION OF THAWING EARTH MATERIALSG. M. PakhomovaDesign and Research Institute for Industrial EnterprisesEastern Baikal Division, Yakutsk, USSRThe author has developed a method for solving one- and two-dimensional problems concerningthe compaction of thawing earth materials. The method was used to investigatethe impact of the thawing regime, The depth of the layer being thawed, and itscompaction properties on trends in the process of compaction of the thawing material.The results achieved are presented as nomograms which allow to predict one the degreeof compaction of various types of thawing and recently thawed materials at any pointbeneath the foundations of buildings or structures at a given point in time. Theymay be used to resolve specific practical problems in location and design.Field data on buildings and structures on frozen - the change of depth of thawing over time (thesoil show that their stability and strength are thermal physical task),significantly influenced by the character of thaw - the pore pressure change over time (thesettlement (consolidation) over time.consolidative task.In this connection, a thorough understanding of The result of the first task, whose method ofthe settlement of thawing soil over time is essen- solution is described by Golovko (19581, Porkhaevtial to determining design requirements that ensure (1970), and others, is the boundary condition forthe operational reliability of buildings and struc- the solution of the second task. To solve thetures built according to the second principle on compaction problem, the boundary conditions of thefoundations in permafrost.region under investigation are defined taking intoAnalysis of the research available on thawingsoil strain (Zhukov, 1958; Vyalov, 1981) shows thatthis is a complicated process dependent on a numberof factors, such as soil type, soil consolidationproperties, thawing conditions, and thickness ofthe thawing layer.The influence of the factors is difficult toquantify due in part to the labour-consuming character,high cost, and long duration of the experimentsand in part to the mathematical difficulties(Tsytovich, 1966).account the results of the thermal physical tasksolution. The region under investigation is dividedinto blocks: the blocks are smallest in the regionof the most intensive compaction (near to the filteringboundary with z=O coordinate). Blockvolumes and resistivities between their centershave been calculated by The formula:The results of research on thawing soil consolidationby hydroanalogy made by this author underProf. S. S. Vyalov are presented in this paper.The hydroanalogy method allows a wide range of where Ci,k - block volume i, k;calculations, to account for the nonlinearity ofa0 - compressibility coefficient of thethe physical parameters and to get a visual picture i,k blocks of the regionof the consolidation process according to the i, k under investigations;factors outlined above.Fi,k - block crOSS-SeCtiOn;The pattern of the compaction (consolidation) ofR;,k resistivity between centres of thethawing soil over time is defined by the of lawsblocks ;thawing and compaction (Vyalov, 1981; Malyshev,ei,Rk block thickness;1966). There is a comprehensive analogy betweenk;,kk - block filtration coefficient.these processes and the process of water movementin the hydrointegrator (Lukyanov, 1947) becauseThen the scaling correlation between the blockthey are mathematically described by the same type volumes and the cross-section of the hydrointegraofequations.tor pipes %,and between the block centre resistivitiesand the hydrogenerator hydraulic resistivitiesMR are determined.where T is a function; x,y, z, and T are independentvariables (coordinates, time); and e, a, b, and Care physical characteristics of the medium.To solve the problem of thawing soil compact ionover time, it is necessary to solve two success ivetasks :M, = c/w (4)% = W Pwhere Mc - the scale volume;C - the block volume;278

27 9w volume of the hydrointegrator;and compaction (B/a) (Figure 1) has been obtained.MR - the scale of resistivities;Visual support of this proposition is given inR the resistivity between block centres; Tsytovich et al. (1966).p - hydraulic resistivity between hydro- When the process is one-dimensional, the changeintegrator pipes;over time in the depth of thaw and the thawing soilcompaction SF might be determined by equations 9Time scale M, and height scale Mh have been com- and 10:puted on the basis of the scale correlations:h, = a F (9)Pii = Mc Mp, (6)i'ih =s U/h, (7)where U is the pore pressure in the blocks of theregion under investigation; andhr is the water level in the hydrointegratorpiesometric tubes.The working scheme of the hydromodel is composedand solved on the hydrointegrator using devicesthat provide the necessary boundary conditions,which in turn provide the only solution.When the assembly is finished and the necessaryboundary conditions have been established, computationcan begin. The hydromodel's elements(hydrovolume w, hydraulic resistivities) are incorporatedinto the operation in time incrementsdetermined by the thermal task solution. Beforeeach successive block connection, the hydrointegratoris switched off and water level readingsthe piezometric pipes are noted. At the moment ofcomplete pore pressure dissipation, when the waterlevel in the piezometric tubes is equal or near tozero, the hydrointegrator is switched off. Thecomplete dissipation criterion is that the waterlevel change in the piezometers over a simulated10-year time period does not exceed 0.1 cm withthe time scale taken into account.The computation results are processed by(Lukyanov, 1974) :where: SF - thawing soil compaction settlement ata given point in time;hr, hr,T - water level in the hydrointegratorpiezometric pipes, initial and at agiven point in time;aoi,k- same as in equations 2 and 3.Thawing soil consolidation has been investigatedusing the hydrointegrator, which might be appliedto the next three cases:Case 1 permafrost thawing during constructioa;Case 2 - permafrost thawing at the full depth ofthe presumed thaw zone, when the thawingsoil layer is underlain low by compressedbedrock.Case 3 - partial permafrost thawing before beginningof construction with subsequentthawing assumed during the period ofexploitation.For all this, the series of tasks with changingparameters of the factors outlined above has beensolved in order to define the consolidation process.On the basis of the interpretation of the solu-tion, the relationship of consolidation extent(Sr/Sp) of thawing soil to the rate of its thawinga a02 004 0.06 am@FIGURE 1 Dependence S:/Sp from B/a. Forthawing soil by different values P; h1, 2, 3 - P = (0.05 + Po); (0.2 4- Po) MPa;Po - dead weight of the thawing soil;P = 0.05; 0.1; 0.2 MPa - compression pressure;a, b, c, - hT,- = 6, 10, 20 m.

280&0.8a6Q400sp = B ETwhere h, -FIGURE 2 a) Relationship S!/Sp from 51, 2, 3, 4 - h = 2, 6, 10, 20 m;b) Dependence of the settlement stabilizationtime upon preliminary thawed soil -G; 1, 2, 3 - P = 0.05; 0.1; 0.2 ma;a, b, c - h,=m = 6, 10, 20 m.a-ST -B -T -depth of thawing ar a given pointtime ;parameter of thaw ratelthermal coefficient;the same as in eq. 8;parameter of compaction rate;time ;in(10)FIGURE 3 Nomogram to establish optimaldepth of thawing before the beginning ofconstruction. a, b, c - h = (0.05; 0.8)h,; 1, 2, 3 - P = 0.05; 0.1; 0.2 MPa.Dividing both parts of eq. 10 into (Sp = aoh,=-P)one obtains an analytical expression for theevaluation of the degree of thawing soil consolidationat the moment of thaw completion:where Sp - stabilized settlement of compaction atthe moment T-;h - depth of thawing at the moment of timer-a. - the same as in eqs. 2, 3, and 8;p - pressure under which soil is thawing.

28 1It has been stated that when (e/a pa) 2 1(Golovko, 1958), soil compaction hasobeen completedduring the process of thawing, but whenB/a pa < 1 (Porkhaev, 19701, thawing soil compacti08nas continued to develop after thawing completion.Data computations on hydrointegrator haveidentified the dependencies of the consolidation ofthe preliminary thawed soil layer 50 years afterconstruction upon the pressure value, layer thickness,and the Soil's consolidation characteristics Golovko, M. D., 1958, Computation method of bowl(Figure 2a,b).of thawing in the structures bed built on perma-It is evident that the consolidation time varies frost: Moscow, TsNIIS, report 141, p. 52.over a wide range (from a month to hundreds and Gorelic, L. B., and Tsybin, A. M., 1979, To thethousands of years), and at small values of G,consolidation theory of thawing soils, &the degree of soil consolidation over a period ofCollection of scientific papers VNIIG, vr 134,50 years is 30-50% of the stabilized settlement SP.p. 119-127.Not only the finite stabilized settlement of the Lukyanov, V. S., 1947, Hydraulic analogy as the newfoundation bed, but also the settlement correspond- means of technical problems investigations,ing to moment '1 can be taken into account. For the Thesis presented by the doctor technical sciencecomputed curve of consolidation of the preliminary (typeprinting): USSR, Lenin Stare Library,thawed layer, dependence SF = 6 K is valid within p. 177.the limits of S$/Sp = 0.8-0.9.Malyshev, M. K., 1966, Computation of foundationThe nomogram has been compiled on the basis ofsettlement built on thawing soils, & Beds,the task solutions. It is used to select the opti- foundations and soil mechanics, no. 4 , p. 20-24.mal depth of the preliminary thawed layer according Nixon, J. F. and Morgenshtern, N. P., 1973, Practothe value of its strain characteristics (A ,a )tical development of the consolidation theory0 0(Figure 3). The nomogram is compiled for the maxi- for thawing soils, 3 Proceedings of the I1mum depth of thawing (h = 20 m) under mean permis- International Conference on Permafrost: Moscow,sible settlement (S = 0.15 m) forNauka, p. 112.Porkhaev, G. V., 1970, Thermal interaction of buildingsand structures with permafrost: Moscow,Science, p. 208.SNPP-18-76, 1976, Beds and foundation of buildingsand structures built on permafrost. Designingc) h/hT- = 0.8specifications: MOSCOW, Stroyizdat, p. 46.Tsytovich, N. A,, 1973, Mechanics of frozen soils:Moscow, High school, 446 p.Tsytovich, N. A,, Grigorieva, V. G., and Zaretsky,The nomogram allows the depth of the preliminar- Yu. K., 1966, Investigations of the thawing soilily thawed layer h relative to the depth of the thaw consolidation, & Beds and foundations: Moscow,zone h,- to be established without additional Stroyizdat, v. 56/NIIOSP, p. 92-112.computations. The hydroanalogy method gives a pre- Vyalov, S. S. and Pakhornova, G. M., 1981, Testcise solution.investigation of thawing soils using field hotThe investigations lead to the following con- punches, & Thawing Soils used as beds of strucclusions:1. The hydroanalogy method gives a satisfactorysolution.2. Developed techniques for calculating settlementand the solutions obtained may be used tosolve practical problems of construction on permafrost,REFERENCESBondarev, P. D., 1957, Strain of building in Vorcutaregion, their reasons and methods of their prevention-:Moscow, USSR AS Publishing House, 98 p.Feldman, G. M., 1966, Solution of one-dimensionalproblem in thawing soils consolidation accountingthe variable permeability and compressi-bility, & Proceedings of the XI11 All-UnionMeeting on EeOlOgy: v. 5, Yakutsk, p. 185-191.tures: Moscow, Science, p. 47-55.Zaretsky, Yu. K., 1968, To the computation of thawingsoil settlement, & Beds, foundations andsoil mechanics, no. 3, p. 3-6.Zhukov, V. F., 1958, Preliminary thawing of permafrostfor construction: Moscow, USSR AS PublishingHouse, 148 p.

THE THERMAL REGIME OF THERMOKARST LAKESIN CENTRAL YAKUTIAA. V. Pavlov and F. E. ArePermafrost Institute, Siberian BranchAcademy of Sciences, Yakutsk, USSRAnnual values of the components of the heat balance of the surfaces of thermokarst lakesand of land areas in the taiga zone of Eastern Siberia were obtained. The radiationbalance and the effective radiation were higher in the case of the lake surface thanfrom a meadow surface; the evaporation from the water surface, 500 totalling m, wastwice as high as the precipitation and 1.8-2.4 times higher than from the soil surfacein meadows. In contrast to the situationland, turbulent heat exchange over thelakes was positive in winter and negative in summer. All components of the heat balanceincreased with lake depth. The mean annual temperature on the lake surface was 4-6'Chigher than that on land. Freeze-up occurred at a water temperature of 1.5-4'C. Inspringtime under-ice warming of the water resulted in temperatures of 10°C and meltingof the ice from below amounted to 35-45% of the total melting. In summertime thesurface water warns up to 25-30°C. Mean annual temperatures of the lake bed arepositive throughout the entire water area. The maximum warming effect on the bottommaterials is produced by a water layer 1-1.5 in m depth. In the central areas of largelakes the annual heat absorption by the bottom is equal to the heat loss but exceedsit as one approaches the shore.Investigations of the thermal regime of lakes,needed in the study of thermokarst processes, wereplaced on a broad footing by Soviet permafrostresearchers in the 1960's (Dostovalov, Kudryavtsevmostly oval-shaped and measure up to several kilometersacross but most measure from several tens toseveral hundreds of meters. The depth of somelakes reaches 10-15 m but most do not exceed 3 m.1967; Gavrilova 1969, 1973; Tomirdiano 1965, 1972; There are numerous lakes only 0.3-0.5 m deep withAre and Tolstyakov 1969; Are 1972; Are 19741, butthe observations gathered were not comprehensi.vean extensive water surface. They usually have aflat bottom covered with silt.enough and usually did nOt cover the annual cycle The climate of Central Yakutia is strongly conofvariation of the parameters under study. Anexperimental study of all components of the thermaltinenral. It is notable for a rapid change ofseasons, large diurnal oscillations of climaticbalance within an annual cycle was first carried elements, and a hot summer with high insolationout under the leadership of these authors during1973-1977 on Syrdakh Lake, a large themokarst lakemeasuring 2X 1 km and up ro 12 m deep. In additionand gentle breezes. The ice-free period lasts4-4.5 months.Central Yakutia is situated within the continutostudying the thermal regime of the lake itself, ous permafrost zone with a maximum permafrost depthgreat attention was given to actinometric andmeteorological observations because the energycirculation within lakes is mainly to due heatexchange through the surface and is thereforeclosely related to atmospheric processes. Theof 450 m. Weak winds, shores overgrown with forestand steep and relatively lofty shore ledges greatlydiminish frictional stirring of lake water. Thehigh insolation combined with low transparency ofthe water and high summer air temperatures produceobservations were made at the center of the lake a strong heating of surface water layers. Theand at varied distances from its shore as well as permafrost lowers the water temperature from below,on land in a larch-type forest in and open meadowareas. The methodology of these observations hasbeen described in several publications (Are 1974;Pavlov 1975, 1979; Pavlov and Prokopiev 1978;These factors render water masses highly stableduring the summer and are responsible €or a varietyof interesting features of the lacustrine thermalregime.Tishin 1980; Pavlov and Tishin 1981).The albedo (A) of lakes up to 2.5 m deep variesThe observational data acquired on Syrdakh Lake from June to September within 0.08 and 0.24 at meanpermit the generalization of the available data set values of 0.11-0.14. The albedo of Lake Syrdakhto the thermal regime of thermokarst lakes ofwith a mean depth 4.5 of m and more transparentCentral Yakutia. These lakes occur within hollow- water averages 0.08 during the summer. During theshaped depressions with steep sides and compara- winter months the albedo ratio of lakes and landtively flat bottoms. In some cases the hollows are varies from 0-8 to 1. A maximum albedo of 0.6-0.8as deep as 40 m but their depth mostly varies with- is observed on lakes in December-January and it isin 5-7 m. They are normally surrounded by woodland decreased to 0.18-0.25 at the time of snow coverwith trees from 5 to 10 m tall. Depending on thestage of development, the lakes occupy a larger ora smaller part of the hollow bottom. They arethawing.Since during an ice-free period the albedoflakes is less than that of meadow areas, the net282

283radiation balance R-Q(l-A) - Ief of an open water completely ice-free 1 month after the establishmentsurface is larger. In the equation Q is totalof an above-freezing daily mean air temperature.radiation, Ief-effective radiation equal to the Since the air temperature is several degrees higherdifference in radiation between the ground surface than that of a thawing ice surface, the latterI, and the atmosphere IA. On the average for the receives a considerable input of turbulent heat.summer net radiation balance for lakes is a byfactor of 1.21-1.34 larger than for meadow areasFor the same reason P the would also be negative ona summer day.(Pavlov 1979). In the winter period the values of For seasonally freezing lakes, thermal flowR are nearly equal and have a negative sign. through the surface (B) can be determined as theThe effective radiation from a lake surface (cf. sum of heat expenditures €or changing the heatTable 1) is 1.4-1.7 times larger than that of a content of the water mass (Bw), for thawing of icemeadow surface, both in winter and in summer. This (BTI), and for heat exchange with bottom depositsis accounted for by the higher temperature of lake (BB). For an intermittently established regime thesurface and by a corresponding increase I,. ofabove components are recurrent within an annualThe evaporation E from the water surface of lakes cycle because the process of lake warming isis in magnitude close to the theoretical maximum replaced by cooling (cf. Table I). The heatvalue. Maximum occurs in July: 8-11 mm/day on LakeSyrdakh. The July total of evaporation is nearlyexpenditure for thawing of ice so is large that itis comparable with a limit change of heat contentone third of summer total which for shallow lakes of water masses. Conversely, the heat expendituremakes up 400-450 nun. The normal evaperoles from for thawing of snow BTS constitutes a small fracthewater surface of Lake Syrdakh reaches 500 mm tion of Bw.which is approximately twice the precipitation and The heat flow across the lake surface becomes1.8-2.4 times the soil evaporation in meadow areas. positive toward the end of March and again changesEvaporation is reduced in shoreline wooded areas. sign 4-4.5 months later. Thermal input into soilHere about two thirds of the annual total of pre- in meadow areas becomes negative 1 month (cf. latercipitation are expended on drainage. Evaporation Figure 1).from snow cover on lakes amounts onl'y to about10-15 mm (Are 19781, or less than 3% of the annualtotal. Heat expenditure for evaporation from lakesis about 80% of R or half the Q for a warm periodand 90% of R per year.TABLE 1 Totals of thermal balance components ofSyrdakh Lake averaged over Sept. 1974-Aug. 1976(10"J/rnZ)ComponentsPeriod=STW TYQ 245 113 358S 21 70 91Ief 74 55 129R 150 -12 138P -13 26 13E 119 3 122B 43 -4 3 0'BTS 1 2 3%I 27 -27 0BW 10 -10 0BE5 6 -6 0Notes: Ts - period with air temperature tA > O"C,Tw - period with tA O'C, T~ - year,S - reflected solar radiation.Turbulent heat exchange P on lakes differs fromthe land where it is positive in summer and negativein winter. On lakes, on the contrary, it isusually positive in winter and negative in springand partially or even completely negative insummer. For example, in 1977 on Lake Syrdakh Pwas negative from April to August. Its monthlymeans for that period varied from -6 to -42 W/m2(Pavlov and Tishin 1981). The negative values ofP in spring and at the beginning of summer areexplained by the fact that the lakes becomeAll the components of B increase with increasingdepth of lakes. On Lake Syrdakh when the depthincreases from 1.5 to 6 m the heat accumulated bywater masses increases three times. For the lakeon the whole it 7-8 is times larger than thataccumulated by soil on land. For a period withabove-zero air temperatures the B/Q ratio for Lakew/100755G250-25-50I II \I \I \\\ /\ /\ /FIGURE 1. Annual variation of monthly mean valuesof heat flow across the surface Lake of Syrdakh (2)and through soil in a meadow (I). area

284Syrdakh amounts to nearly 0.12 while the B/R ratiois 0.21. The mean annual temperature of the surfaceof lakes is by 4-6°C higher than that on landbecause of large heat amounts accumulated by watermasses.The temperature regime of water masses has beenstudied in derail on small and large lakes (Are1974, Tishin 1978). Usually the lakes become iceboundin the first half of October, this occurring1.5-2 weeks later on larger lakes in comparisonwith smaller ones, at a comparatively high temperatureof water of 1.5-2'C in small shallow lakes andof 3-4°C for large deep lakes. The temperaturedistribution with depth is nearly isothermal withgradients of 0.2-0.3'C/m. Only near rhe watersurface and bottom do gradients become steep.In the winter period lake waters cool due toatmospheric cooling. Heat flow from the bottomdoes not produce any increase of water temperatureafter the lakes become icebound, which is accountedfor by a relatively high temperature of the waterbefore the formation of ice cover and by a decreaseof the amount of heat flow due to the coolingeffect of a frozen mass. There are no observeddiurnal variations of temperature below ice. Oncethe lake becomes ice covered, the increasedvertical temperature gradients of water within thenear-surface layer disappears rapidly but remainsunchanged within the near-bottom layer throughoutthe entire winter, reaching 2-3"C/m toward the endof March. Within the main mass of water thetemperature distribution in depth is close toisothermal. In shallow lakes the water coolsduring the wintertime to the freezing point and thewater in deep lakes cools to 2-3°C.The spring warming of the water starts at theend of April after the daily mean air temperatureshave traversed O"C, that is long before ice breakupon lakes. Initially the warming is produced bythermal flow from the bottom. The first manifestationsof the thermal effect of solar radiationpenetrating the ice appear in mid-May after thesnow cover disappears completely and the ice thicknessis decreased to 1 m. Subsequently, the watertemperature below the ice increases rapidly due tothe penetrating radiation and can be as high as10°C by the beginning of the ice cover break-up.During the period of under-ice warming, theWaKer temperature distribution depends on the sizeof lakes, their depth, and water transparency. Inlakes that are less than 1.5 m deep, the penetratingradiation warms not only the water but also thebottom sediments. For instance, within a lake 1.35m deep, at the water temperature of 8.5'C, thebottom temperature was measured to be 6'C. Withinsmall turbid lakes 2-3 m deep the warmingpenetrates to 1.5 m while deeper layers remainnearly isothermal prior to break-up. Within largeand deep lakes with a transparent water the warmingpenetrates to greater depths. For instance, warmingpenetrates to a depth of 6 m in Lake Syrdakh.In this case the temperature gradient graduallydecreases with depth. The period of warming belowice is notable for daily fluctuations of watertemperature of 1°C to a depth of 1 m. The radiationwarming of the water below ice initiatesintensive thawing of ice from below, which constitutes35-45% of the total thawing for the timebefore the start of ice cover movements.The summer temperature regime of water is establishedafter the lakes become ice-free in the firsthalf of June. Smaller lakes open 10-15 daysearlier than larger ones. After breakup there issome decrease of temperature within the upper onemeterlayer of water but thereafter a rapid warmingstarKS and even within a few days the temperatureof surface layers on large lakes usually reaches10-15°C and on small lakes 15-20'C. In this caseon lakes deeper than 1.5-2 m a normal three-layertemperature distribution in depth is established.The thickness of epilimnion is 1-1.5 m on smallerlakes and 2-3 m on larger ones; that of metalimnion,respectively, ranges from 0.5 to 4 m. Thevertical temperature gradients in the smaller lakemetalimnion are 20-25"CIm while those for largerlakes are 2-3"C/m. The surface water layers arewarmed up to maximum temperatures of 25-30°C. Inthis case the epilimnion decreases in thicknesswhile on lakes up to 2 m deep the temperaturedistribution sometimes becomes rectilinear throughoutthe entire depth, particularly during the daytime.The vertical temperature gradients reach8"C/m. Diurnal fluctuations of temperature wirhinthe epilimnion reach 3-4°C and on occasions 6°C andthose within the metalimnion do not exceed 1°C.The summertime cooling of water masses StarKS inthe first half of August. In this case the epilimnionincreases in thickness and a icothermalcondition is eatablished throughout the entiredepth at a temperature of about 10°C in the secondhalf of September even in the deepest lakes. Subsequently,in the period prior to freezing thewater temperature decreases and the character ofthe temperature gradient remains unaltered.There are no substantial horizontal temperaturegradients of water €or most of the year. Only atthe onset of the summer warming in June and in thefirst half of July in shallows less than 1 m deepis the water temperature higher than that withinthe same layer of a deep part of lakes.An important parameter needed in calculations ofthe thawing of permafrost below water reservoirsis the temperature of the bottom surface. It islargely determined by the water temperature anddepends on the depth of a lake. The observationson 12 lakes have been used to infer a dependence ofthe mean annual temperature of the bottom surfaceon the depth for smaller shallow lakes and for LakeSyrdakh, shown in Figure 2. The plots in Figure 2show that the maximum warming effect on underlyingground is produced by a water layer of 1 m thicknessfor smaller lakes and of 1.5 m for larger ones.A further increase of the water layer of smallerlakes leads to an abrupt decrease of bottomtemperature. For larger lakes this effect is muchweaker. The maximum temperature of the bottomsurface of smaller lakes is about 6°C and thar oflarger ones is 7'C. It is found that under climaticconditions of Central Yakutia the mean annualtemperatures of the bottom surface are above zerothroughout the entire water area of lakes up tothe water edge.The heat exchange of water masses with thebottom is characterized by a heat flow Bg, whichvaries over the annual cycle both in value and insign, In the part of the water area of lakes thatdo not freeze up to the bottom, BB becomes positivein the second half of May and then reverses sign in*

28 5G12open talik below a lake at a considerable distancefrom the shore the permafrost effect is missing andthe annual heat absorption of the bottom is equalto the losses (cf. Table 1).The above relationships of energy exchange inatmosphere-water medium-underlying ground systemshold true not only for thermokarst lakes of CentralYakutia but also for the whole taiga zone of EastSiberia.REFElUNCES3456mFIGURE 2. Mean annual temperature of the bottomsurface versus depth: (1) Lake Syrdakh (Pavlovand Tishin 1981), (2) small lakes (Are 1972).the first half of September. The maximum amount ofheat of about 30 MJ/(month.mZ) is received by thebottom in July and the maximum loss of heat of17-20 MJ/(month m2) takes place in September or inOctober. The maximum heat absorption by the bottomon Lake Syrdakh is observed at a depth of about 1.6m. The dependence of this quantity on the predominantdepth of lakes is illustrated by figureslisted in Table 2, obtained by Gavrilova (19731,Are (1974), and Pavlov (1979).TABLE 2 Heat absorption of bottom of lakes fora seasonPredominantLake depth (m) BB(MLT/m2SyrdakhProkhladnoye,TyungyulruKradenoye4.5 582.0-2.5 63-660.2-0.5 138For smaller lakes with closed taliks below lakesand for larger lakes near the shore the annual heatinput into the bottom exceeds substantially theheat loss. Irreversible heat absorption of thebottom is spent for maintaining the talik below alake within permafrost. For larger lakes with anAre, A. L., 1978, Snow cover of Central Yakutia," some features of its radiative and hydrothermalregime, i~ Beat exchange in permafrost landscapes:Yakutsk, IM SO AN SSSR, p. 30-42.Are, F. E., 1972, Das Warmeregime der Seen Zentral-Jakutiens: Verhandlungen der InternationalenVereinigung fur Limnologie, 18, S. 574-579.Are, F. E., 1974, Thermal regime of shallow lakesof the taiga zone of East Siberia (in theexample of Central Yakutia), In Lakes of thepermafrost zone of Siberia: Novosibirsk: Nauka,p. 98-116.Are, F. E., and Tolstyakov, D. N., 1969, On penetrationof solar radiation into water: Meteorologiyai gidrologiya, No. 6, p. 58-64.Dostovalov, B. N., and Kudryavtsev, V. A., 1967,General cryology: Moscow, Izd. Mosk. un-ta,403 p.Gavrilova, M. K., 1969, Microclimatic and thermalregime of Lake Tyungyulyu, & Questions ofYakutia geography: Yakutsk, Kn. izd-vo, v. 5,p. 57-72.Gavrilova, M. K., 1973, Climate of Central Yakutia:Yakutsk, Kn. izd-vo, 119 p.Pavlov, A. V., 1975, Heat exchange of soil withatmosphere at northern and moderate latitudesof the USSR: Yakutsk, Kn. izd-vo, 302 p.Pavlov, A. V., 1979, Thermal physics of landscapes:Novosibirsk, Nauka, 285 p.Pavlov, A. V., and Prokopiev, A. N., 1978, Heatexchange of soil with atmosphere in conditionsof a larch forest in Central Yakutia, &Heatexchange in permafrost landscapes: Yakutsk, IMSO AN SSSR, p. 3-29.Pavlov, A. V., and Tishin, M. I., 1981, Thermalbalance of a large lake and of the area adjacentto it in Central Yakutia, Structure andthermal regime of frozen earth materials:Novosibirsk, Nauka, p. 53-63.Tishin, M. I., 1978, Temperature regime of watermasses of Lake Syrdakh, & Geothermophysicalresearch in Siberia: Novosibirsk, Nauka,p. 58-66.Tishin, M. I., 1980, Thermal regime of the bottomof a large thermokarst lake in Central Yakutia,- in Permafrost exploration in development areasof the USSR: Novosibirsk, Nauka, p. 40-47.Tomirdiano, S . V., 1965, The physics of lacustrinethermokarst in polar plains and Antarctic Regionand cryogenic transformation of earth materials:Kolyma, no. 7, p. 30-34; no. 8, p. 36-40.Tomirdiano, S . V., 1972, Permafrost and exploitationof highlands and plains: Magadanskoye kn.izd-vo, 174 p.

PREDICTION OF CONSTRUCTION CHARACTERISTICS OF SLUICED MATERIALSUSED IN FOUNDATIONS UNDER PERMAFROSTCONDITIONS AND IN SEVERE: CLIMATESV. L. PoleshukDesign and Research Institute for Industrial EnterprisesEastern Baikal Division, Yakutsk, USSRDuring engineering preparation an of area for COnStruCtiOn in permafrost areas bymeans of hydraulic action it is essential to predict the thermal interaction of thesluiced and natural materials and their structural properties. The investigationrevealed that the use of sluiced and underlying materials as foundations can behandled in three different ways: the sluiced material forms the levelled buildingsurface; a combination of sluiced materials and the underlying materials is usedfor the building foundation; no load is exerted directly on the underlying materialand only the sluiced material forms the foundation. With these schemes in mind,requirements in terms of the construction properties of materials are examined andprinciples for using them as foundations are formulated.Building in permafrost areas requires specialengineering preparation of the territory that takesinto account the protection of the environment.Construction codes permit the use of permafrostground as a building foundation in accordance withtwo conditions: in a frozen state (condition 1)and in a thawed or state of thawing during operations(condition 2). When either condition mentionedabove exists, the engineering preparation3f the site must provide for the conservation ofto regions of Western, Central, and Eastern Siberiaand to the east of BAM.Several years ago in permafrost regions severalembankments were constructed for different purposesthe calculated temperature regime of the foundation using sluiced materials. For instance, in 1960-62soil and for the preservation of the natural envir- this method was used to form the site of theonmental conditions. In order to drain stormiwater present river port in Yakutsk and to construct aand other kinds of surface water from the construc- dike to protect the port area. To the north oftion site and to preserve the vegetative and soil Krasnoyarsk, Yakutsk and Magadan, a number of smalcovers, the engineering preparation of a site tailing storage dams for ore enrichment plants wasshould be carried out by using fills during ver- built using the sluice method. The extraction oftical levelling and grading. As a rule, shear cuts bottom sand and gravel deposits in river beds andare not permitted. Bedding fills are used in the other water basins, where they are in a thawedconstruction of road embankments, accesses, build- state all year round and easily developed usinging sites for one or more buildings.hydromechanical means, has been made possible byDuring the engineering preparation of a con- the use of sluiced materials under such extremestruction site for large industrial enterprises and conditions.large-scale developments (towns, cities, individual These first attempts to use sluiced materials inhousing), it becomes necessary to construct differ- permafrost revealed a number of specific characterenttypes of embankments of considerable size. istics of these materials which form when they areFrom a technical-economic point of view, the used as foundations. These features hinder theoptimum method for the use of fill in construction direct application of experience in building onmust be selected during the engineering preparation sluiced materials in temperate climate zones. Theof large areas. Both foreign and domestic practices main feature is the thermal interaction betweenin temperate climate zones widely employ the "hydro- fill and the underlying perennially frozen naturalmechanical" method in earth works related to ground and a tendency for the development of cryogenicprocesses. This interaction determines themunicipal construction. This method is cheaper andless labor-intensive in comparison with conven- formation of the structural properties of sluicedtional ''dry" technology. It does not require the marerials and their suitability as foundations.construction of quarries and roads, the extensive It became necessary to carry out specialuse of trucks and machinery, or the transport and investigations on the properties of sluicedplacement of soil into the fill. The net cost of materials in permafrost. These investigations werethe soil extracted and placed by the hydro-mech- conducted by the Yakutsk Division of the "Zabai-anical method is 1.5-3 times less, while thelabor required is 15 times less than in the conventional"dry" method, The high degree ofefficiency of fill construction by hydro-mechanical means has promoted the widespread of usesluiced materials for the engineering preparationof sites in different cities of the Soviet Unionincluding Moscow, Leningrad, Kiev, Gomel, Gorky,Omsk, and Archangel. In recent years, the areas inwhich sluiced materials are being used has expandekalpromstroyiniiproekt" Research Institute of theMinistry of Eastern Construction at a specialexperimental site in Yakutsk. The site issituated on the Lena River floodplain on the bank286

287of its channel which floods every year. Thealluvial deposits mainly consist of fine-grainedsand 14-20 mm thick underlain by sandstone andaleurolite bedrock. The sand stratum includessilty sediments, peat and, in some places, layersof dusty, sandy loam and sandy clay from 0.3 to3.0 m thick. The floodplain is characterized bytypical meadow vegetation; the average thicknessof the soil's vegetative layer is 10-20 cm. Thedepth of seasonal thaw varies from 0.9 to 2.6 mdepending upon soil type and surface cover. Theentire area of the floodplain is characterized byflat topography. The annual fluctuation of soiltemperature varies from -0.3 to -1.9'C. Moisturecontent of the alluvial deposits usually is in therange of 20-30% and ice content is 14-22%. Thedistribution of ice along the section is relativelyuniform, and the soils are characterized by massivecryogenic texture. Information on the permafrostthickness in the floodplain is contradictory butat the site it exceeds 100 m. This was demonstratedby drilling a special well: the lowerlimit of the frozen zone was not established.Experimental fill, having a total volume of300,000 m3 and varying in thickness from 1 to 6 m,was constructed by the sluice method on a 12-hectare test site.The processes of heat exchange were studied. Thefoundation was tested by static loading and theconstruction techniques were examined. The rateof soil drainage was determined. The technicaleconomicefficiency of the use of sluiced materialsfor the construction in Yakutsk was evaluated.The investigations outlined above demonstratethe feasibility of developing the floodplain adjacentto the city for large-scale constructionusing the sluice method. An area of about 800hectares has to be developed at an average depth ofa 6-7 m sluiced embankment. Therefore, Yakutskwill be the first building site where constructionon sluiced materials in permafrost is to be performedon a large scale. In the absence ofanalogous construction in permafrost, the decisionwas made to begin the floodplain development withthe construction of three experimental buildings onsluiced materials. They represent 5-storey residentialbuildings which are being constructed bydifferent methods on different types of foundations(pile, columnar and foundations-enveloped). Examinationof these types of foundation and the techniquesused to build them on beds composed of sluicedmaterials should provide the optimal solutions fortheir future application in large-scale development.I UiFIGURE 1 Schemes €or using fill soil as a bed:(I) Foundation does not influence fill; (11) Fillis influenced by the foundation together with underlyinglayer; (111) Foundation loads are totallytransferred to the fill: 6 = width of foundationbottom; H = computable compressed layer; N = loadingon foundation; p = pressure on the soil underfoundation bottom. 1. foundation; 2. planningmark; 3. limit of seasonal freezing-thawingthe sluiced layer; 4. surface of natural soil;5. limit of seasonal freezing-thawing in thenatural soil before sluice; 6. plot of distributionof compressed pressure; 7. foundation bottommark.

28 8Depending upon the vertical levelling done for embankment will be 10 m or m ore in the case of bigthe engineering preparation of the site and the use skeleton soils.of sluiced materials as the foundation bed, three The deformation requirements for the srructuralscenarios can be distinguished (Figure 1) :properties of the sluiced and underlying soils areI. The foundation does not exert load on the the same as for scheme 111. If underground ice,embankment fill; it functions as the levelling ice-rich soils, frozen peat and other types of soil,layer.which undergo considerable settling during thawing,11. The foundations of structures exert loads on are found in the underlying natural layer sluicingthe embankment fill and its natural underlying must be done with an eye toward restriction of itslayer.thermal effect on the underlying soil. The possi-111. The embankment fill accepts all of the loads bility that the underlying soil could thaw duringexerted on it by the foundations and structures. the construction and operation of buildings must beThe underlying layers are not affected by the completely eliminated. The third scheme expandsfoundation loads.the limits of application of the second principleIn the first scheme the use of a fill embankment, of soil use as a foundation bed, because the depthirrespective of the use of foundations, requires of the layer of sluiced materials promotes thethat there be no evidence of heave in the sluice; formation of an extensive, positive temperaturegravel, sand or a combination of both are used. thaw zone. Under natural conditions it can takeIt is necessary to provide high load bearing more than 15 years for this layer to freeze.capacity of the natural ground. It is compressed Measures designed to accelerate this freezing prounderthe sluiced layer and frozen in the com- cess are frequently ill-advised due to technicalpressed state, which improves its structural and economic considerations.properties. As for Yakutsk, when scheme 1 is used, The choice of scheme depends upon the thicknessfreezing takes place over the course of one winter of the fill and the characteristics of the naturalif the fill height does not exceed 2 m.topography of the area being developed. Therefore,If foundation works for the account of soil in the engineering preparation for future construcfreezingalong the lateral surface, it is recom- tion on the Yakutsk Lena River floodplain, allmended to use fine-grained soils. Their highest three schemes could be adopted.load bearing capacity will be reached under con- When the fill embankments are constructed by theditions of rota1 moisture capacity and maximum sluice technique in permafrost and severe climaticdensity. Maximum density is provided by theconditions, the problem of choosing the correctspecial selection of fractions. The best degree scheme for the use of sluiced materials as a founof pore filling in the mixture of two fractions dation bed is of particular importance. Thisis obtained when the small fraction weight 30% is problem has evoked considerable controversy among(Bannik 1976). Filter particles must not be frost- specialists. The problem, first of all, relates toheaved and have a dimension greater than 0.1 rn acceleration of the time required to freeze the(Dalmatov and Lastochkin 1978).sluiced materials, while increasing the thicknessWhen scheme I1 of sluiced fill use has been of this layer. In addition, the engineers arechosen, it is necessary that maximum load bearing interested in obtaining a frozen foundation bed ascapacity of both the sluice materials and the fast as possible. Periods of freezing and stabiliunderlyingground be maintained. Under sluicing zation of the temperature depend on the intensitythis soil thaws, but under the weight of the sluiced of sluicing, the season when the work is beingmaterials it is compacted and a redistribution of performed, moisture content of the alluvial fillmoisture takes place. It is recommended to take and also upon the design of building foundations.measures for draining the thawed layer in order to In order fo use permafrost as a foundation bed (inprevent frost heave. Experiments show that sandy thawed or frozen state) it is recommended to gosoil compresses during the thawing period. When with the natural development of cryogenic processescompression is completed they might be used as beds. in the new fills. Technological and engineeringThe calculation of strain deformation must be done solutions must facilitate intensification of theseaccording to norms established for two-layered processes and under no circumstances impede orfoundation beds. In the case of Yakutsk, theoppose them. This makes it possible to provide thedegree of settling under working loads does not necessary reliability of the beds and stability ofexceed allowable standards. Strain deformation of building and structures.the underlying soil can be reduced when the warming Insofar as temperature regime of the fill soileffect of sluicing decreases. Depth of thawing can affects the condition of the ground water, itbe diminished by depositing sluiced materials on determines to a great extent the soil's COnStructhefrozen ground in the spring, increasing the tion properties. In connection with this, thesluicing intensity and by thermal insulation of the prediction of fill thermal conditions is particunaturalsurface. In some cases, it appears to be larly important for differant technological schemesfeasible to obtain maximum depth of thawing ofof the use of sluiced materials, thickness of thenatural soils for their melioration in the sluicing alluvial layer and conditions of thermal exchangeprocess. The technical and engineering techniques between the alluvial layer and the underlying soilthat allow for the control of this process within in the bottom of fill and the atmosphere. For thedefinite limits in a prescribed direction are well conditions in Yakutsk, the problem of such predicknown.tion was solved for the firSK time using hydro-When scheme 111 for the use of sluiced materials integration and computer technology at the Permaisadopted, the thickness of working layer exceeds frost Institute of the USSR Academy of Sciencesthe computed thickness of the linearly deforming (Konstantinov and Votyakova 1981).layer. Therefore, the total depth of the sluiced

These calculations proved that there is a tend- ture), In this case, steps must be taken toency for permafrost to form in the alluvial embank- prevent subsequent soil freezing.ment fill under the heat exchange conditions in In the process of sluicing big skeleton soilsYakutsk. However the freezing time indicated by and when schemes 11 and I11 are used it is advisthesepredictions was considerably longer than for able yo use foundations with developed surface ofthe results of natural experiments.support, which make greatest of use the resistanceBased on the results mentioned above and new of alluvial soil to normal pressure.experimental data from a test polygon and an experi- When principle 1 is employed the freezing periodsmental construction site,the scientists of the can be considerably (2-3 times) shortened when suchYakut research division have now developed more pre- measures have been undertaken as construction ofcise methods of calculating alluvial soil tempera- ventilated sub-basements, forced cooling of theture conditions using a computer. The calculations soil by blowing cold air through the cavities ofmake it possible to get accurate data on fillfoundations and engineering lines, the use offreezing periods as a function of its thickness, automatic closed convective or condensation coolingtime and sluice intensity, soil composition and system, cleaning of snow cover, etc.moisture distribution taking into account the ef- The optimum use of sluiced materials, intensifectof the inhomogeneity of thermophysical proper- fication of natural cryogenic processes as a functieson fill depth. An algorithm for the numerical tion of nature (climatic and frost-soil conditions),solution of this problem has been developed. and specialized designs for buildings and structuralMathematical models make it possible to select foundations make it possible to manage the construc-any principle for the use of fill soil as a foundationbed. It should be remembered that formulationof the principles for definition of the conditions€or the use of sluiced materials changes in comparisonwith standards available. This makes itnecessary to take into account thermophysicalprocesses in alluvial soils.tion properties of foundation beds on sluicedmaterials both during construction and during theuse of buildings and structures.REFERENCESThus, the formulation of the first principle's Bannik, G. J., 1976, Technical melioration of soils:definition under conditions for the use of sluiced High School, Kiev.materials might be written as follows:Dalmatov, B. J., and Lastorkin, V. S., 1978, Gaspipe- alluvial and natural underlying soils of bedconstruction in heaved soils: Nedra.are used in a frozen and freezing state (freezing Konstantinov, J. R., Makhotko, S. P., and Li, G.E.,may occur during construction and operation of a 1981, Temperature conditions prediction ofbuilding or structure),alluvial fill and its bed, & Engineering inves-For the second principle:tigations of frozen soils: Novosibirsk, Nauka,- alluvial and underlying soils are used in aSiberian Division.thawed state (thawing of underlying soils at a Votyakova, N. J., 1981, Computation of sluice soilcalculated depth is assumed during the deposition and its bed freezing, & Composition and thermalof sluiced materials, building or use of a struc- conditions of frozen soils: Novosibirsk, Nauka.

ANALOG METHODS FOR DETERMINING LONG-TERM DEFORMABILITYOF PERMAFROST MATERIALSL. T. RomanDesign and Research Institute for Industrial EnterprisesEastern Baikal Division, Yakutsk, USSRThe paper demonstrates the possible use of temperature-and-stress-time analog methodsfor predicting long-term deformation of frozen earth materials. A solution wasachieved which a11-0~ one to process the data from ground testing using a sphericalpunch by analog methods.To compute foundations composed of elastict' t/aq;frozen soil it is necessary to predict settlementag - temperature-time reduction ratio.for a period comparable to the lifetime of thebuilding and construction. The reliability of theprediction depends on the choice of the optimalmathematical model. It should be capable of reveal-The equation is-compZicated to use. In practice,the reduction coefficient is determined accordingto the dependence of the specimen's compliance uponing the strain character during the primary phase the effect of the rime of loadiag under differentof loading and of giving an exact quantitativedescription of the deformation over a time oftemperatures. Compliance is the relationship ofrelative strain to stress (0):several orders of magnitude greater than theexperimental one.Studies of the rheological properties of frozenJ = 616 (2)soil (Vyalov, 1978) have shown that strain issignificantly influenced by temperature. As temperaturelowers, creep of soil decreases, otherthings being equal. In its turn, the effect oftemperature on the strzin value is interconnectedand interequivalent with the effect of time: underMethods of strain computation based on the uniaxialtension and compression (Urzhumtsev, 1975) andon spherical punch pressing (Takahashi, 1964) havebeen the test techniques widely used in frozen soilmechanics. They simplify the use of analog methodsfor frozen soil strain prediction and permit thestress that is an equal ratio of either instantane- combination of the specimen strength and strainous or long-term strength over a longer time period tests.in low-temperature soil the same strain value Using the analog method it is necessary to estabappearsas in high-temperature soil, Therefore if lish the character of the thermorheological behavitheinfluence of temperature and time on soil de- our of the samples under loading. In the theoretiformationis determined using the results of short- cal prerequisites of the temperature-time analogyterm specimens in high-temperature tests under two types of such behaviour are considered (Urzhumtloading,long-term soil deformation at low tempera- sev, 1975).tures might be predicted. An analogous relation-1. Under temperature change, compliance dependsship has been observed between the effect of stress only upon the displacement of the macromolecules.and time on deformability. It suggests thatIsothermal curves of viscous-elastic compliancetemperature and stress-time analogy techniques may obtained for different temperatures are similar.be used to evaluate deformability of frozen soil, The reduction ratio ag. which permits the general-These techniques intensify the strain one by of rhe ized curve under comparative experimental conditionsaffecting factors (e.g., temperature increase) in to be plotted, is the function of the singleorder to observe the strain under the increased argument of temperature.rate and to extrapolate the results of short-termGeometrically, the sense of this proposition is:experiments for longer time periods.under temperature change the compliance curves J vsTo make this extrapolation it is necessary to In t are barely displaced along the time axis and thedetermine the time reduction ratio (a). Its bas is parallelism of their displacement is not disturbed.is the correlation of compaction intensity a as This significantly simplifies the determination offunction of time and temperature (Urzhumtsev, 1975):the reduction ratio a0 because temperature changestipulates only the horizontal time shift of the(1) compliance.This type of strain is the characteristicfeature of thermorheologically simple materials.2. When strain is complicated by the effect ofwhere g(t,e) - the function of the compactionintensity;p,Po - densities under temperatures 8,00respectively;t - time;structure transformations, the relationship J vsIn t also becomes complicated. A vertical shift aswell as the horizontal one has been marked. The290

291FIGURE 1 Compliance of the log peat (R = 20%, yo = 1.03 g/cm3,yr = 1.5 g/cm, W = 4.95) according to the spherical punch test.1 - generalized curve plotted as for thermorheologically simplematerials.2 - generalized curve plotted as for thermorheologically complexmaterials.reduction ratio depends on both the period ofstrain and the temperature. These are referred toas thermorheologically complex materials.Computation of the reduction ratio for thermorheologicallycomplex bodies is a complicatedproblem, so, when the effect of vertical shift isinsignificant, it may be ignored. In this case onemay plot the generalized curve as for thermorheologicallysimple materials. The temperature-timeanalogy does not permit accurate long-term strainprediction when the vertical shift factor cannot bedetermined.To apply the analog method to frozen soil it iswaKer content, determined by calorimetric method,is shown in Table 1.TABLE 1 Unfrozen water content (WH unit fractions)in peat test specimens vs. temperatureO°C -2.5 -4 -6 -8.5 -9.5 -13 -25.5 -28WH 2 1.3 0.9 0.7 0.6 0.55 0.51 0.5necessary to understand whether the frozen soil is The most appropriate metho,d,must be chosen toa simple or complex a material.determine the relationship between the settlementThe results of frozen soil tests with a 22-mm soil strain modulus load and the punch dimensionsdiameter spherical punch (Roman, 1982) have been for frozen soils to calculate the strain valueanalyzed. Under all temperatures the sphericalusing the results of the spherical punch test.punch was loaded so that its settlement was similar Experimental analysis showed that the modulusat any given moment in time. It makes identical of strain of frozen soil may be computed from thethe stress influence upon strain, and revealed only rigid spherical punch pressing into the elasticthe effect of temperature. The specimens were made half-space (Bezukhov, 1953). In this case, as wellfrom an upper layer of bog peat. The degree of as for thawed clayey soil, the radius of the punchpeat decomposition was from 18 to 20%. To provide print as the initial parameter in the solution musthomogeneity, the air-dried soil was sieved. The be equal to the radius of the truncated segment ofdiameter of the sieve was 4 nun. The specimen was the punch being submerged in the soil.then saturated with water and kept in the sieve for Since the compliance (J) is the recipracal48 hours covered with a filter for free drainage. magnitude of the strain module using the aboveThe soil mass prepared by this technique was used solution it can be determined by the formula:to prepare metaform blocks lOOX 10x100 mm. Compactionwas by layered tamping and freezing in theunderground laboratory at 4.2"C. The specimensJwere then kept at the test temperature. The experimentshad been carried out in the chambers an of=4s 3/2 (d-S) 13(1-p2)Punderground laboratory and in a heat-proof room where S is the punch settlement (cm);where temperature conditions were provided by theeffects of outside air temperature in winter. Thep is the Poisson ratio; andP is the load on the punch.experimental data for analysis were obtained underisothermal conditions. The physical properties ofIn Figure I, the compliance of the tested specithesoil tested were as follows: soil density, mens in conditions J vs In t calculated by eq. 31.03; soil skeleton density, 0.172; particle den- is represented.sity, 1.5; moisture, 4.95; and initial freezingThe generalized curve has been plotted -13'C fortemperature of soil water, -0.08"C. The unfrozen for both rhermorheologically simple materials (curve

292FIGURE 2 Compliance with X-parameters being taken into accountand generalized curve plotted as for thermorheologically simplematerials.1) and thermorheologically complex ones (curve 2). TABLE 2 K-values for specimens testedThe procedure for plotting the generalized curvesby both methods is detailed in Roman (1982). Toevaluate the degree of reliability of any method, B°C -2.5 -4 -6 -8.5 -9.5 -13 -25.5 -28i.e. to decide whether the frozen soil is a thermo- K 0.625 0.746 0.815 0.85 0.867 0.876 0.883 0.884rheologically simple or complex material, long-term,30-day tests were conducted. The conditions of thebase experiment were preserved. The results show Plots JK vs In t and the generalized curve plottedthat frozen soils should be referred to as thermo- for thermorheologically simple materials are shownrheologically complex materials: the test points in Figure 2. It can be seen that the K parameterare on curve 2.Factors that disturb the frozen soils' continumallows the influence on the compliance of the structuremodifications connected with moisture phaseand homogeneity are the main reasons for stipulating transition to be reduced, and simplifies long-termthe vertical shift of the compliance curves. To strain prediction.plot the generalized curve, results of experiments Interpretation of the experimental data on thecarried out under a wide range of temperatures were J vs. In t coordinates shows that the family ofused, so the influence of unfrozen water content compliance curves has converged at the pole. Thewill be different in either test.abscissa of the pole was approximately equal toThe volume of soil occupied by unfrozen water and the time log of the atoms' free oscillation (10-13)gases as well as the volume occupied by ice andsoil particles can be determined. The relativeand the ordinate was approximately equal to thevalue of the instantaneous-elastic compliance. Tocontent of ice and particles (K) is easily expressed calculate the pole ordinate for the specimenas a proportion of the soil volume:tested, the module of instantaneous elasticity EyK = Yck[ l/y, + (Wc- WH) /Y*I (4)was obtained with an ultrasonic technique (Urghumtsevand Maksimov, 1975). Instantaneous-elasticcompliance taken as a reciprocal value Ey was from1. 1-6 to 2. 1-6 ma-'. It is one to two orders ofmagnitude less than the compliance value computedon the total strain of the specimens (elastic andresidual). It makes it possible to determine thewhere Yck - density of the soil skeleton;yr - soil particle density;Wc - total moisture;Wn - unfrozen water contentyn - ice density.To take the influence of the gas content andunfrozen water on compliance into account, thestress should be referred not to the geometricsquare of the specimen but to the square occupiedby soil particles and ice. An approximation isacceptable if it is proportional to the relativecontent of soil and ice (K). Therefore, the compliancevalue related to the source of soil particlesand ice will be equal to:J - 6k/(r =k-JK(5)For the experimental data given in Table 1, K-valuescalculated with eq. 4 are represented in Table 2.pole ordinate, which is equal 0. toThe availability of the pole suggests the plottechnique of curve construction. The rays crossingthe compliance curves are drawn. The coordinatesof the points of the rays' concurrence and eithercurve have been determined. The relationship Jxvs. In t from Bt-Bo under temperature-time analogyand ai - o0 under stress-time analogy have beenplotted. (ao, Bo ate stress and temperature correspondingly,and the base curve has been plotted forthem). Extrapolating these relationships to theordinate axis we determine the JK and In t valuescorresponding to ui-u0 = 0 or Bi-Bo = 0; i.e. wehave the coordinates of the points of concurrenceof the secant rays with the base curve. Usingthose coordinates, the base curve for a period of

293FIGURE 3 Plotting method of generalized curve construction usingthe log peat experimental results by the stress-time analogy method(e = 4.5%).time exceeding the experimental one by severalorders of magnitude was plotted. Figure 3 is anexample of generalized curve plotting based on theresults of frozen peat tests using the stress-timeanalogy. In practice, the generalized curve coincideswith the curve obtained by the conventionalmethod, i.e. a rigid horizontal shift to the compliancecurvep to the right of the reduction ratiovalue.The secant ray technique proposed in this paperis less labour-consuming and it permits the periodof strain prediction to be increased.A series of experiments carried out to plot the‘generalized curve allows long-term strains to bepredicted under other than base stress. Interpretationof the experimental data shows that theplotting relationships lnJK vs u - o0 determinedfor either fixed time form a famfly of parallellines (Figure 4A). Therefore it is easy to get theorbit line InlK - oi - o fot the time being equal toeach value within a preaicted period including themaximum one (tmax). For this purpose it is necessaryto find 1nJK value on the abscissa of the1dK vs ‘7i-uo plot taken from the base curve fortma. Across this point a line is drawn parallelto the experimental ones. This line is the compliancerelationship with stress for time periodtmax-For the temperature-time analogy method the1nJK vs lnt relationships prove to be linear.Their extrapolation to the given time period allowsthe long-term compliance under all experimentalvalues of t to be determined (Figure 4b).The reliability of the results of frozen soillong-term strain prediction by the analogy methodhas been verified in two ways:1. Comparison of the results of the strain predictionbased on the creep equations suggested bya.b.FIGURE 4 In JK relationships: a) In JK - ui - uo plotted on test data given in Figure 3.b) In JK - In t plotted on test data given in Figure 2.

294Vyalov (1978) and those based on the time-stressanalogy method.2. Comparison of the punch experimental settlementcomputed for the case when the strain modulehad been determined by the analogy method. Thesame data were used in as the first case.The equation was written as a power function,accounting for the similarity of the creep curves.A comparison of the results is given in Table 3.TABLE 3at 4.5'CTechniqueSignificance of bog peat compliance testedunder pressure of 0.2 MPa for 908 hr.JK. 10-"Pa-lAt the end of the stabilization period, the settlementwas determined by the layer-adding technique.Comparison of the experimental and the computedsettlement values show a good agreement for thefirst step of loading. For the last steps, thepredicted values were somewhat less than theexperimental ones. This was caused by ignoring thefact that the loading of previous steps occurredover longer periads of time. In conclusion itshould be pointed out that settlement prediction ismost reliable by the analogy method. It accountsfor the character of the soil rheological properties,in particular the nonlinearity of the straindependence upon stress.Using unconfined compres-REFERENCESsive strength 1.45Bezukhov, N. J., 1953, Basis of the theory onCreep equation 1.68elasticity, plasticity and bearing capacity ofStress-time analogy 1.39frozen soils: Moscow, USSR Academy of Science,p. 188.Roman, L. T!, 1982, Predictinn of creep of frozenpeat by the temperature-time analogy method, &Soil rheology and engineering geocryology Pub-The punch test was used to test the second methodlication.of comparison of the settlements. In the under-Takahashi, M., Shan, M., Taylor, R., and Tobolyky,ground laboratory (0 = -4'C) , a cylindrical hole 30A., 1964, Master curves for some amorphous polycmin diameter and 17 cm deep was drilled in a sandmers. J. Appl 1. Polymer. Sci., v. 8, no. &,layer of natural composition. It was filled withp. 1549-1-564.peat moss under layered tamping.Urzhumtsev, Ju. C. and Maksimov, P. D., 1975, Pre-After freezing and temperature stabilization a diction of polymer material strain ability:17-cm-diameter punch was installed. A jack provided Riga, "Zinatne", p. 416.incremental loading. The process of settlement overVyalov, S. S., 1959, Rheologic ability and bearingtime and its dependence upon stress has been fixed. capacity of frozen soils: Moscow, USSR AcademyThe frozen peat compliance at the same temperature of Science, p. 188.was also determined by the stress-time analogy. Vyalov, S. S., 1978, Rheological basis of soilThe generalized curve could be plotted and the mechanics: Moscow, High school, p. 447.relative settlement determined far these specimens.

RESISTIVITY LOGGING OF FROZEN ROCKSA. M. SnegirevPermafrost Institute, Siberian BranchAcademy of Sciences, Yakutsk, USSRThe article examines the present state of some aspects of resistivity logging as ameans of studying the cryolithozone, and the results of investigations in the pastfew years. The efficacy of resistivity logging is determined by the differentiationof the electrical properties of frozen ground, by the accuracy of measurement andby the technical conditions of drilling. The potential of the major methods is beingfully realized in holes drilled without using fluid solutions as long as the valuesfor electrical resistivity of the frozen rocks do not exceed 800-1000 ohm-meters. Anincrease in the range of measurements turned out to be possible only by using measuringequipment with a high input resistance of and new technical elements that substantiallyimprove the accuracy and operational characteristics of resistivity loggingequipment where parameters of constant and low frequency electric fields were beingmeasured in dry holes. The investigations carried out and the observational errorachieved allow one to apply resistivity logging studies of low-gradient processesoccurring within the permafrost zone, to improve the methods and technology of studyinggeoelectrical cross sections, and to study variability in the physical and chemicalproperties of permafrost in relation to the effects produced by external physicalfactors.Resistivity logging as a method of obtaininginformation about frozen rocks is based upon theassumption that the geocryological section can berepresented as spatially distributed electricalparameters of the medium of study (for example,resistivity, electrochemical activity, dielectricpermittivity), varying in time and depending oncomposition, ice content, concentration of mineralsalts in ice and pore moisture, temperature, andother characteristics of rocks. In principle,finding correlations between these parameters willcontribute to a mass determination of the geotech-rock studies in boreholes and should be taken intoaccount in field data interpretation.In this connection we now consider, in the firstline, the conditions of conducting resistivitylogging in boreholes that are drilled using a fluid,whether the fluid remains in the borehole or shaftis removed after drilling operations-are completed,or that are drilled using compressed air.The interpretation of resistivity logging dia-grams and electrical field parameter measurementsin boreholes filled with drilling fluid is markedby the appearance of an unfrozen layer in thenical characteristics of permafrost that are needed vicinity of the borehole shaft by a high-gradientby building workers and specialists studying heat temperature field perpendicular to the boreholeand mass exchange in permafrost and the deep freez- axis, and by the properties of the drilling fluid.ing of the Earth's crust, as well as by geologists The unfrozen layer produced by the drilling surandgeophysicists for the purposes of reliable rounds the borehole shaft (on occasion its thickinterpretationof field data.ness reaches 1-2 m (Maramzin 1963) and allows onlyStudy of resistivity logging with regard tolithological boundaries within the cross sectionpermafrost is justified given the rich background of the borehole to be revealed through resistivityof experience associated with the application of logging (for example, Musin and Sedov 1977). and toresistivity logging in prospecting for oil, coal, a considerable extent it hinders or even rules outand ore in areas where no permafrost is present. the possibility of studying the electrical proper-In a more specific context-that is, the deter- ties of the permafrost levels.mination of analytical and experimentally staristi- In the presence of such a layer and temperaturecal relationships between the recorded components gradient normal to the borehole axis, large resisofan electric field and the properties of the tivity installations have to be employed to revealmedium being studied-this problem becomes extremely the cross section andto investigate only relativelycomplicated, not only because of the specialthick frozen rock benches. The use of drillingfeatures of permafrost but also because of thefluid in drilling operations plays an importantmetrological characteristics of measuring instru- role in assessing the thickness of the permafrostmentation and equipment, and peculiarities of the zone using resistivity logging diagrams of thestate of frozen rocks in the vicinity of a borehole, natural electrical field. The experience accumuwhichare in many respects determined by the drill- lated in the Soviet Union (Volodko 1976, anding method.others) indicates that the accuracy of such deter-This last factor is known to play an important minations is fairly high.role in selecting electrical methods for frozen In boreholes where the drilling fluid is295

296removed after drilling is completed, there also therefore of operations in each borehole.arises a relatively thick layer of modified rocks. All of this requires further solution of theThe processes of thawing at the time of drilling theoretical, methodological, and technical probandof refreezing in the vicinity of the borehole lems of resistivity logging of dry boreholes beshaftafter drilling operations are completed lead cause they provide the best conditions for theto irreversible changes in the rock properties. In study in the permafrost zone.particular, once drilling is terminated, it isTheoretically, due to the wide range of electricpossible to apply methods using direct and alter- al conductivity values of frozen rocks it is practicallyinfeasible in the investigations to givenating current in order to subdivide the crosssection lithologically, but after the temperature preference to resistivity logging methods usingregime has recovered it is difficult to resolve either direct or alternating electromagnetic fields.this task. In a number of cases the high electrical The primary application in the Soviet Union andresistivity of frozen rocks makes it impossible to abroad of resistivity logging using direct currentapply frequency methods in investigations (forcould be due to the relative simplicity of theexample, the induction method) and postulates technical and methodical capabilities of this kindspecial requirements to the measuring technique of research, but analysis of the published data andfor elecrrical conductivity, natural electrical of results of special research shows this explanafield,and polarizability (for example, ensuring tion is premature.low contact resistance at the electrode-rock con- Several problems face resistivity logging, namelytact, the use of instrumentation with high inputresistance, and others).Similar measuring conditions are created withinboreholes that are drilled through permafrost whilepurging the face with cooled compressed air. However,experience shows that these boreholes aremore suitable for studying the geoelectrical crosswithin the lithological-stratigraphical levels, thesection of permafrost because the maximum thickness thickness of particular rock benches, etc.), idenofrocks warmed by the drilling does not exceed tification of the structure of natural and artif-0.2-0.3 m, and the natural temperature regime re- icial electrical fields in the vicinity of thecovers in the course of a few days (Balobaev et borehole al. and within the area of study, so and forth.1977).These problems will be successfully resolved throughFor several reasons, notably the lack of water the use of appropriate measuring installations andin the winter time and the difficulties of prepar- a sufficiently high accuracy of measurements ofing and using unfrozen drilling fluids, drilling electrical field parameters is ensured.operations using compressed air is widely used in The former (except for the solution of specialthe North for drilling test and prospecting holes. problems such as detection of ice in the boreholeThe volume of such drilling for the Yakutian cross section, evaluation of the amount of unfrozenRepublic alone exceeds many hundreds of running water, etc.) does not require special developmentsmeters. At the same time, techniques for resis- and is satisfied comparatively readily on the basistivity logging of these boreholes, judging by the of an extensive scope of theoretical and methodavailablepublications (e.g., Bakulin 1973, Akimov ological investigations in the field of oil, coal,1973, Hunter 1975, Jackson 1956, Avetikyan andand ore resistivity logging.Dorofeev 1970, Bakulin 1967, and others) have not The latter requirement however can only be metyet been adequately developed.after the main factors that distort the results oMost of the publications include an analysis of measurement of electrical parameters are identifiedthe results of investigations, but technical and and removed. We now consider these factors in themethodical questions are discussed to a lesser context of resistivity logging using direct currentextent, although logically it is they that should The contact resistance electrode-frozen rockbe emphasized in connection with the specifics of (pel) predetermines the choice of a generatingthe investigations being conducted. Poor informa- device and measuring instruments for the resistivitytion about the results of the investigations and logging installation. For a dry borehole drilled inimperfect resistivity logging techniques for frozen frozen rocks, pel is of particular importancerocks in dry boreholes seem to be the reasons why, because the known methods for decreasing and ensurinthe practice of engineering-geological and geo- ing the stability of this value (moistening, increasecryological work, the resistivity logging method is of the contact area, enhancement of clamping of thebeing used to study only an insignificant number electrode of to the hole wall, etc.) are not alwaysboreholes. In addition, these boreholes are most feasible. For example. increasing the electrode'sfrequently filled with a specially prepared fluid area of contact with the hole wall decreases pel,and observations are made with techniques developed limits the minimum dimension of resistivity loginoil and ore geophysics using standard measuring ging installations and necessitates complex calinstruments.In this case the rocks near the bore- culations of the geometrical coefficient of thehole shaft, particularly dispersive ones, become probe (Oparin 1978, and others). In this case, themechanically not solid and therefore there are value Pel nevertheless remains dependent on thefrequent cases of a tack of electrical probes. It electrical resistivity of rock (pn),is understandable that the effectiveness of suchresearch is on the whole low not only because ofthe need for performing a number of additionallabor-consuming operations but also in connectionwith time limitation of such observations andthe identification of particular features of a geoelectrical cross section (determining electricalparameters of individual levels, their time varia-tion and space variation, etc.), the refinement ofthe structure of a geocryological cross section(ice content distribution in the cross section andTests of various borehole electrode designs(brush, spring-type) and others) have demonstratedthat a maximum value of pel is reached as high as500 Kohm; therefore, to obtain a relative error ofmeasurement 6 = 1-20%, the input resistance of the

297measuring device should be of at least 50 Kohm. It apply such resistivity logging installations, whosecan be seen that operating instrumentation withsuch input resistance is possible only whendefinite microclimatic conditions are provided inreadings would be independent of these factors. Inparticular, probes that are more than 5-6 times thediameter of the borehole satisfy quite reasonablythe field laboratory, which is not always feasible. the solving of most of the problems; in this caseIn one of the latest papers (Snegirev et al.1981) it is proposed to dampen the surface of thecontact electrode-rock with an electrolyte contheborehole diameter can be omitted in interpretingthe observations. Efficient is also the applicationin probe designs of special devices that preservetained in a nonpolarizing electrode. Automatic the separation of clamping borehole electrodes (forcontrol of the electrolyte flow foreseen in the example, .Borisenko et al. 1977, and others).design ensures a value of 5 pel 100 Kohm.In addition, stable electrode potential (no morethan 3-5 mV) makes it possible KO study in a dryborehole the natural electrical field and the inducedelectrochemical activity of rocks.One other property of the measurements may includecurrent leakage from the current into linethe measuring line through the surface of the resistivitylogging cable.Figure 1 exemplifies some results of resistivitylogging, as obtained within one of the regions ofYakutiya.The scientific objective included an assessmentof the abilities of resistivity logging installationsto distinguish between various frozenlithological-stratigraphical levels. To aid comparison,a gradient probe and middle and verticalgradient installations were employed.In general, the influence of current leakage in The last two modifications were used to precluderesistivity logging installations upon the resultsof the investigations is known, as are the steps tobe taken to avoid leakage (Geophysicist's Manualshielding effects in the results of the investigation.For that purpose, a system of fixed feedelectrodes installed on the Earth's surface or1961). Their observance in investigating boreholes within the borehole was used to create d.c. afilled with drilling fluid normally yields stable,high-precision results. For dry boreholes the fulfillmentof these conditions is necessary butinsufficient.As a result of friction of the electrodes on theborehole walls, the detaching ice particulatesvertical electrical field.The measuring system of all installations (Figurele) incorporated nonpolarizing electrodes, a resistivitylogging cable, and a millivoltmeter withinput resistance of more than 50 Mob. The electrodepotential drop and natural electrical fieldtouching the relatively warm cable thaw to produce potential were compensated for at every point beforea wet film on its surface between the probe elec- cutting in. The measuring step was 0.5 m.trodes. Such a film may also result from electro- The set of all elements of the system and allowlyteleakage from the non-polarizing electrode or ance for special features of frozen rock resistivityfrom moisture that penetrates into the borehole logging described above provided at least 3% errorfrom a seasonally unfrozen layer, as well as from of measurement.other causes. The electrical conductivity of therising layer is unstable and varies due to variationsin its thickness, salt concentration, etc.Depending on voltage, the electrical resistivityThe geocryological cross section depicted inFigure 1 is representative of typical rocks of theregion, exhibiting in the vicinity of the boreholea uniform thickness, horizontal bedding, and differofthe rock, and the electrode earthing resistance, ent electridal conductivity. The behavior of thethe amount of current leaked may be substantial. pk plots within each lithological difference is dueIt is easy to show that with increasing rock both to the peculiarities of the formation of theresistivity and electrode earthing resistance the geocryological cross section and the to propertiesrelative fraction of leaked current on the cable of the measuring installation being used.surface between the electrodes increases, other The curve pk on the interval of rocks of trapconditions being equal; therefore the measurementerror will increase. (According to calculationsand experimental observations the relative errorreaches 100% and more.)This fact increases the existing requirementsformation (0-40 m) has a maximum in connection withthe different degree of metamorphism of the centraland peripheral parts, while the peaked appearanceof the pk plot obtained with a gradient probe isaccounted for by current shielding effects producedfor insulation resistance among all structuralby rock cracks. Given fixed feed electrodes (Figureelements of the resistivity logging installation lb, IC), the curve displays a smooth behavior.(not less than 50 Mohm) and requires the develop- We have similar plots on the borehole intervalment of special methods for eliminating the current between 95 and 150 m, composed of benches ofleakage between borehole electrodes that occur over dolomites, marls, and limestones, which have differthesurface of the cable. One of these devices, ent electrical resistivities. By reducing theproposed in Snegirev et a]. (1981), breaks theeffects of shielding, the positions of separatecurrent-conducting film by hollow packings, made of benches of seams can be reliably determined.dielectric hydraulic insulating material shaped The middle part of the cross section made up oflike cones bell-mouthed downwards and mechanically sand from the Permian age is characterized by smoothsupported by the cable between the electrodes. pk plots. Despite the different conditions ofThe evaluation of the influence of complicating electrical field excitation, the pk values do notfactors, such as the diameter of the borehole wall, practically differ from each other, 50 the sandthe Earth's surface, and the altered rock zone, upon cross section, especially its upper part (50-70 m),other kinds of measurement results can in principle can be regarded as uniform and isotropic.be carried out analytically and via modeling.For a specific conduction work of this intervalWhile excluding the possibility of using them, can be selected as a reference in determining transneverthelessin practical work it is advisable to verse resistances (Alpin 1978).

egradient-pde uerficalgradientA5. OM?. ON AB400m. MtV=40mA MNBA6MIFIGURE 1 Results of resistivity logging.1) crack dolerites; 2) sand; 3) alteration of marls, limestones, dolomites;a) pk curve, gradient probe; b) Pkcurve, middle gradient installation; C)Pkcurve, vertical gradient installation; d) temperature t°C and weightinghumidity W X of frozen rocks; e) layouts of measuring resistivity logginginstallations.Comparison of the plots in Figure lb and ICsuggests that, in principle, the use of a middleThe example just considered reflects an insignificantfraction of work on the effectiveness ofgradient installation makes it possible to deter- resistivity logging methods. (See Akimov 1973,mine the transverse resistance of seams that form Bakulin 1967, Snegirev et al. 1980, 1981, andthe middle part of the cross section because within others).the borehole it helps create a vertical electrical In summarizing, the following has to be emphas-field, ensures the measurement of fairly highvalues of electrical potentials, and removes theinfluence of shielding effects on the measurementresults. Nevertheless, operations with this installationare complicated by the laborconsumingized. It is advisable to conduct studies of geoelectricalcross sections of frozen rocks withresistivity logging within boreholes driven withoutthe application of drilling fluids. The technicaland methodological problems can be overcome if theoperations needed to provide reliable grounding of factors that influence the accuracy of observationsthe feed electrode in the dry borehole shaft and and by distort logging plots are taken into considerathepresence within the borehole of a feed cable, tion and eliminated.which displaces the measuring dipole. ThereforeThe investigations carried out permit measurementthe vertical gradient installation for a study of of electrical field parameters within a dry boreholeshallow dry boreholes provides a number of advan- with a relative error of 1-3%; which makes ittages as compared to the known point resistivitylogging technique KC.The essence of these merits lies in the possipossibleto utilize logging installations in experimentsand observations of weak-gradient processesoccurring within permafrost.bility of obtaining plain-shaped plots of observa- The peculiarities of resistivity logging of rockstions, uncomplicated by shielding effects, that outlined above do not cover the diversity of factorspermit solution of a major logging problem, namely that researchers may encounter, but we feel they athe determination of the parameters of rock seamsthat have different composition and properties. Inaddition, it is also possible to run continuouscrucial. The degree of reliability in determiningthe electrical parameters of the cross section usingresistivity logging dara-will largely determine theresistivity logging of rocks within a dry borehole. successful application of electrical methods inNo attempts have been made to address this problem areas of development of permafrost. Therefore therethrough the use of three-electrode probes because is a need for further development of the techniquesof the extreme difficulty of producing a currentstabilizer that operates where there is sharpvariation of load. With the vertical gradientinstallation, the need for such a stabilizer nofor borehole investigations. An in-depth study andaccumulated experience will make it possible, takininto account the state-of-the-art of the measuringtechnique, to start implementation of the mostlonger arises, while the variation of the installa- advantageous continuous resistivity logging oftion coefficient as the measuring dipole moves along frozen rocks in dry boreholes.the borehole shaft can be compensated for.

299REFERENCESAkimov, A. T., 1973, Logging in shallow dry boreholesaimed at studying geotechnical and geodynamicalcharacteristics of permafrost, I1 InternationalConference on Permafrost: Yakutsk,Yakut Publishing House, p. 18-25.Alpin, L. M., 1978, Determination of transverseresistivity of strata from measurements in bore-holes: Izvestiya WZ, Geology and prospecting,no. 4, p, 52.Avetikyan, Yu. A., and Dorofeev, E. A., 1970, Highqualitylogging of boreholes for determininggeoelectrical properties of rocks, Engineeringinvestigations in civil construction: Synopses4(7), Ser. 11, Moscow, p. 61-65.Bakulin, Yu. A., 1967, An instrument for resistivitylogging of dry boreholes and results of itsapplication in geocryological investigations:Komi, p. 213-219.Bakulin, Yu. A., 1973, On the use of resistivitylogging of dry boreholes in determination ofcomposition and some properties of frozen rocks:Proceedings of the VNII for hydrogeology andengineering geology, v. 62, p. 59-65.Balobaev, V. T., et al., 1977, Manual on thermistorcalibration and their use in geothermal measurements:Yakutsk, p. 28.Borisenko, Yu. N., et al., 1977, Design of the probefor the apparent resistivity 1 method, In Geophysicalinstruments, v. 62, Leningrad, "Nedra,"p, 108-111.Geophysicists Manual, 1961, v. 11, Moscow, p. 157-158.Hunter, J. A., Borehole geophysical methods inpermafrost: Geological Survey of Canada, Paper75-31, p. 67.Jackson. Equipment and method of borehole logging,US patent no. 2755450. 17.07.56.Maramzin, A. V., 1963, Experience of drillinggeological prospecting boreholes in frozen rocks:Moscow, Gosgeoltekhizdat, p. 21-26.Miller, A. V., 1970, The technique of resistivitylogging of dry boreholes, & Proceedings of the2nd Republican scientific-theoretical conferenceof young geologists of the Kazakh SSR: Ust-Kamenogorsk, p. 181-182.Musin, A. M., and Sedov, B. M., 1977, Some peculiaritiesof borehole resistivity logging underconditions of permafrost: Abstracts of papersand communications 'Wethods of engineering-geological investigations and mapping of thepermafrost region," v. 2, Yakutsk, p. 30-32.Oparin, V. N., 1978, Depth range of boreholeelectrometry, Journal Physico-technical problemsof mineral resources exploitation: Novosibirsk,Nauka, v. 4 , p. 84-87.Snegirev, A. M. et al., 1980, Some peculiarities ofresistivity logging (apparent resistivity) offrozen rocks in dry boreholes: Izvestiya WZ,Geology and prospecting, no. 6, p. 76.Snegirev, A. M. et al., A probe for resistivitylogging of boreholes, Patent certificate no.802891.7.2.81, Bulletin no. 15.Snegirev, A. M. et al., A non-polarizing electrode.Patent certificate no. 894655. 30.12.81,Bulletin no. 46.Snegirev, A. M. et al., 1981, Geoelectrical crosssection of frozen rocks of the Viluy Riverwatershed area, & Field and experimentalinvestigations of permafrost: Yakutsk, p. 7-16.Volodko, B. V., 1976, The use of the AR method indetermining the thickness of frozen terrigenousbanks, & Regional and thermal-physics investigationsof frozen rock in Siberia: Yakutsk,p. 212-214.

STRESS-STRAIN CONDITION AND THE ASSESSMENT OF SLOPE STABILITY INAREAS OF COMPLEX GEOLOGICAL STRUCTURE UNDERVARIOUS TEMPERATURE REGIMESS. B. Ukhov, E. F. Gulko, V. P. Merzlyakov, and P. B. KotovInstitute of Civil EngineeringMoscow, USSRCalculations of the stress-strain condition and the stability of rock masses innorthern regions are complicated by the effects of temperature and by associatedphysical and mechanical processes. In terms of thermodynamics these processes arecontrolled by the stress tensor, temperature, concentrations of individual componentsand phases, crack density tensor, and by irreversible internal parameters. Equationsof.the condition of the rock, including the above-mentioned variables, complete thesystem of equations of equilibrium expressing geometric relationships heatmass andexchange. It is possible to simplify the proposed scheme to the level of engineeringpossibilities by taking into account adequate representation of results. In thiscase a set of engineering investigations essential for assessing the stability ofthe sides of reservoirs under different regimes would include the following: 1) Onthe basis of data derived from engineering exploration the real structure is representedin the form of engineering and geological models and reflecting the peculiaritiesof its composition, structure and condition; 2) the laws governing the behaviorof rocks under loads in frozen, thawed, and thawing conditions are determined underboth field and laboratory conditions. On this basis the physical and mechanicalproperties of the rocks of separate zones and the elements of the actual slope aredetermined. Geomechanical models of the rock mass are then on built the basis ofthe data obtained; 3) items 1) and 2) allow one to compile calculations of the stressstraincondition of the slope under varying conditions; 4) on the basis of the dataderived from calculations of the stress-strain condition minimum stability safetyfactors may be determinedeach element of the layout network, potential slip planesmay be identified and integral safety factors of slope stability may be calculated.Analysis of the stress-strain condition and thestability of rock masses in northern regions includesthe physical and mechanical processes connectedwith temperature. For a general case,thermal strains of frozen and thawing rock arecontrolled by the behavior of skeleton and icecrystal lattice, phase transitions, structuraltransformations, water and air compressibility,chemical reactions, and migration and filtrationof moisture. In this connection, the classicalconcept of thermal strainsE= aae (1)should be more accurate. Here E is the relativestrain, a is the thermal expansion factor, and A0is the temperature change.In frozen masses of complicated geological composition,several nonhomogeneous types can bedistinguished. The nonhomogeneity of propertiesis conditioned by the nonhomogeneity of the masscomposition, its structure, and state (Ukhov 1975).Nonhomogeneity caused by phase transitions (frozenand thawing zones) is clearly seen within a homogeneousrock mass. It is necessary to apply thermodynamicsto describe the processes in such a medium(Merzljakov 1980) eTo describe a thermodynamic system one shouldchoose the so-called external parameters characterizingconversible processes. First, there arethe stress tensor components Gij (or strains Eij)and temperature 8. The influence of the intensivephase transition zone is taken into account byadding concentrations of components and phases mi,variable in this process, to the mentioned variablThe degree of fissuring described by crack densitensor B;* (Vakulenko 1974) also influences themechanical properties of rock to a considerableextent. Thus, thermodynamic functions, namely fullthermodynamic potential 9, are the functions offour variablesand a potential change in a reversible process mabe expressed byAlso taking into consideration that in the reversibleprocess,d$ = p dm + SdO - E..dOij1 1 11300

30 1we getwhere p1 is the chemical potential of a componentor phase 1 and S is the entropy of the system.of using eq, 6.Here and further, summing up is implied by repeated Describing the mechanical behavior of rock inindices. Tensor E ~ in ~ general, , is a tensor of terms of non-linear equations 7 or 8 causes a nontlnitestrains. It should be noted that eq. 4,linear equation system of the stress-strain stategenerally speaking, makes it possible to take into calculation problem. The solution of the problemaccount mass exchange processes by introducing of is possible only by means of numerical methodsthe source of the K-component:% = Gkdt (6)where Gk is weight flow per time unit. By disintegratinga thermodynamic potential (eq. 2) intoTaylor's series regardless of initial stressedstate and differentiation in accordance with eq. 5we getthe intensive phase transition zone. One of theversions may be found in Plotnikov (1978). Thevariable surface of frozen water in such a case isa known temperature function (Ershov and Akimov1979). Comon calculation of the stress-strainstate and filtration is one of the indirect waysaccording to the iteration scheme, provided actualnonhomogeneous and boundary outlines are taken intoaccount. Let us explain the scheme by a particularexample. In the case of an isotropic nonlinearelastic medium, eq. 7 is equivalent to the relation-11, = 2VIT,5(10)+ "ijklokle + * . . (7)Here, the constant coefficients are respectivelyequal to the following:whereIx = xkk/3,11 X = J(xLL-x22>2 f (x11-x3d2 + (x22-x33)22 2 2f 6(~12 + X13 + x23).....................................As a rule, not every elastic constant Cijkl isindependent. It is possible to demonstrate that,for instance, for fissured rock the number ofindependent constants does not exceed six. Insteadof eq. 7, it is possible to use the equivalentrelationshipwhere coefficients Cijkl and aij are functions ofvariables Okl,o, Rkl, and mp, which are determinedexperimentally.Equations of state 7 or 8 complete the equilibriumequation system, geometric relationships, andequations of heat-mass exchange. As has been shownby Porkhaev (1970), mass exchange processes may beneglected in most cases while calculating thermalfield in mass rock. Therefore further we shallconsider that heat movement inside frozen and meltedzones and displacement of a "demarcation" line arecarried on only by conductivity heat exchange.Stephen's problem solution may be obtained accordingto enthalpy techniques, which take into accountHere, X and p are elastic characteristics in termsof Lame factor, concentrations mi are considered tobe temperature functions, and their change areevaluated by a, the coefficient, thus,a = a' + 61-3ml/a@(Merzljakov 1980). To determine the parameters ofrelationships 9 and 10 I,, IIE, I, 110, k, 0 itappears to be necessary to add two dependenciesthat are determined experimentally:$i(fE, IIE, I, IIu, 1-r6, 0) = 0, i = 1,2 (11)where &is the Lode parameter. It is assumed thata stress tensor and a strain tensor are similar(Q pol; temperature changes during the experimentand parameter CI may be determined by the supplementaryexperiments. Dependencies 11 also includestrength conditions. Then, using equilibrium equationsin displacements(U'U. .I i +(!J Uj),i+ 2 0 'ukk>,j + (Ye)1,J a ,i+x -0j(12)where i,j = 1,2,3. We can draw up an iterationsolution of nonlinear elastic problem, in the sameway as was done by Gulko (19791, but taking intoaccount temperature changes. Equation 12 makes itpossible to determine displacements with the givenelastic constants X and p, thus determining I,,IIE, and PI. I, and XI, may be determined from

302eq. 11. and lore a ccurate valu es of A and p fromeis. 9-and 10. The process is repeated. It shouldbe noted that eqs. 9 and 10 express the so-calleddeformation theory, while relationship 8, generallyspeaking, is non-holonomic.To describe irreversible processes in the system,it is necessary to consider particularly choseninternal parameters along with the external parametersof a medium (Sedov and Eglit 1962). The socalled"non-compensated" heat dq' is added to theright side of eq. 4. As the simpliest hypothesisdescribing creep, it is possible to assumedq' = K(dx/dt)dx, K>O (13) the formation of the dangerous collapse surface isrevealed and serial of potentially collapse surwhereK is scalar functions of external parameters faces is chosen. 5) For the series mentioned above,and internal parameter. Non-holonomic relations 8 integral total stability safety factors (K,) areunder condition 13 turn into the following:defined as the ratio of epure square of ultimateshear stresses at the dangerous surface to epuredEij = CijkldOkl t aijdO + A. .dx ... (14) square of acting shear stresses along the same1Jsurface. The design surface is chosen from thepossibly dangerous surfaces with minimum K, value.where coefficients Cijkl, "ij, and Ai. are externalBelow, as an example, the results are of givenparameters, functions, and x. If necJssary, due tothe slope evaluation of the K, of the complicatedthe experimental data, hypothesis 13 can be alteredgeological composition of a northern water-storageand internal parameters can be added.reservoir. The slope in question consists of 12The full equation system described above, eventypes of rocks whose disposition and the locationwith the stated limitations, cannot be completedof the supposed great wreck are shown in Figure 1.because of the great expense of the research underDue to the lack of experimental data, the sequencecomplicated geological conditions. By simplifyingof quasi-stationary (temperature and mechanical)the scheme to the capacity of an engineer and to states is under consideration to make eq. 7 moreconsiderable reliability of the results obtained,concrete. The calculations are carried out on theacceptable practical solutions of the given problembasis of the thermo-physical and mechanical properriesof rock in frozen, thawing and thaw states.are possible.The suggestions made above concerning mechanical The design versions and calculation results of Ksbehavior of frozen-thawing rock is the basis for theare given in Table 1.solution of a stress-strain state problem. The In different periods (pre-construction, construcproblemof evaluating slope stability is closely tion and maintenance of a dam) the rock's physicalconnected with it, and the ultimate stable state ofstate and its mechanical properties may be quitethe rock is considered to be the final state. Indifferent. To compile the calculation schemes, 26this case, the stability safety factor (Ks) of aquasihomogeneous rock areas were considered. Theslope may be defined as the ratio of critical parapermafrostand thawed areas are demarcated inmeters of the problem (failure load, critical em- Figure 2-6 by a dotted line. A boundary of a slopebedding of slopes, etc.) to the actual spatial para- melting area at filling of a water storage reservometers. However, this method was not a success in (Figures 5 and 6) is meant for 50-year maintenance.practice since it does not have enough practicalIn deciding upon the design (calculation) schemesgrounds. In this connection, in design practice and the numerical solution of the problem, thetraditional techniques are used based on thechoice of the dimensions of a calculation area isdefinition of (Ks) as the ratio of forces keeping important. The dimensions were derived from thea creeping fill to forces shifting it along the test calculations (other conditions being equal).given surface of sliding. Experimental data K, of Preliminary calculations and analysis carried outrelevant to this technique have been stored which in this way demonstrated that marking the dimen-assures slope stability. However, traditionaltechniques have a significant shortcoming which isto the following effect: confining and shearingforces are determined rathet approximately andwithout any connection with the solution of astress-strain state boundary-value problem. Boundarycondition influence and changes in maintenanceperiod, force, and temperature influence cannot beaccurately taken into consideration.responsible for its physical and mechanicalbehavior. 2) Stress components are calculated forthe boundary area in question by the solution ofsome physical problems (e.g., thermo-technical)determining a state of the object and a stressstrainstate problem. 3) Strength safety factors(Kss) are considered .to be the ratio of ultimatevalues of shear stresses (the latter is determinedby the condition of strength, e.g. Coulomb'sequation) to the maximum acring shear stresses, thestress field being known. 4) By analyzing theminimum Kss values and the stress-strain statepattern, the area that is evidently responsible forsions of a calculated area by Version 1 (Figure 2)caused erroneous results for K,, which is 10-14% byVersion 2 (Figure 3-6) and to the error not exceeding1-2% in calculation versions (the area ofVersion 2 is increased by 35% in comparison withVersion 1). For example, the value of K, for aslope in the preconstruction period is 1-09 and0.95, according to Versions 1 and 2, respectively.As shown, the results obtained are considerablydifferent. In the first case, the slope is stable,in the second it is not. Thus, when applyingnumerical methods of evaluating slope stability,The following method of evaluating slope stabilityof complicated geological composition, developingupon suggestions of ukhov (19751, may be considereda rather important specification of traditional one should be very accurate in outlining the calcutechniques:1) On the basis of the design data andlation area.the geological and geomechanical research an ofThe following conditions are assumed as theobject, the geomechanical model and design schemecalculation area boundaries: at the lateral boundareworked out. They reflect its structural peculi- aries, horizontal displacements are equal zero; toarities, composition, state, and other factors

303YFIGURE 1 Geological scheme of a left bank and ariver bedFIGURE 4 Calculation area schematic in constructionperiod (Section 1-1)""--FIGURE 2 Calculation area schematic in preconstructionperiod (Version 1)FIGURE 5 Calculation area schematic in maintenanceperiod (cross-section is higher than darn)YY/ z2""-6FIGURE 3 Calculation area schematic in preconstructionperiod (Version 2)

304TABLE 1 Calculation Results of Minimum Stability Safety Factor (PSIK, valuesCalculationnumberDescriptionWith a crackWithout filled withcracksbreccia1 Preconstruc'cion period (naturalslope) 1.35 1.182 Construction period (designout, "discharge" stressconsidered)Similar t o No. 2 but without"discharge" stressMaintenance period, natural,melt slope at TWLSimilar to No. 4, at instantdischarge of NTWL up to tailwaterlevel and non-stabilizeddepression curve, stress dischargeinvolvedSimilar to No. 5, but atstabilized depression curveMaintenance period, crosssection1-1 (within a damand upstream), "discharge"stress considered at constructionperiod cutSimilar to No, 7, regardless"discharge" stresses1.261.571.461.281.231.421.731.091.391.381.201.131.321.60Similar to No. 7, but atinstant discharge NTWL up toTWL and non-stabilized depressioncurve, "discharge" stressinvolved 1.33 1.2110 Similar to No. 9 but atstabilized depression curve 1.36 1.27at the lower boundaries vertical displacements are dangerous surfaces are composed of two regions: theequal to zero; and at the upper boundaries external first includes a crack plane, the second a formationloads are zero. During the construction and main- surface III. Table 1 lists minimum Ks values. Intenance periods, in shear areas external forces are the versions without cracks, minimum Ks valuesassumed to be equal to discharge forces. Hydro- correspond (in different versions) to surfaces I1static water pressure upon frozen mass outline,and 111, for versions with cracks-to surfaces IV.accordance with breaking of the area into finite Comparison of calculation results shows that the Kselements, is applied in terms of horizontal andvertical components of discretion forces. Afterthe normal top water level is removed, the "disofa slope during different periods (pre-construction,construction, and maintenance) undergoesdifferent changes. Rock thickness during construccharge''forces are applied to the areas of frozen tion period causes considerable change of a stressmassoutline free of hydrostatic pressure.strain state and K, value decrease.For every design, K, has been calculated for theprobable sliding surfaces disposed in the area ofminimum values of local strengrh safety factors.The typical surfaces (I, 11, 111) corresponding tominimum values of K, are presented in Figure 2-6.In the calculated versions with a supposed crack,When a water storage reservoir is filled, slopestability increases due to the horizontal componentof hydrostatic water pressure. At maximum waterdischarge and a stabilized depression curve,K?tends to minimum values. The latter is conditlonedby the size of the thawed slope area and by the

305difference in mechanical rock properties in frozen,REFERENCESthawing, and thawed states. In a dam cross-sectionan extra load from upstream fill increases slope Ershov, E. D., and Akitnov, U. P., 1979, Phase moisstabilityin all calculated versions.ture composition in frozen rock: Moscow, MoscowThus, calculation result analysis makes pos- itUniversity.sible to draw the following conclusions:1. The differences in rock's strain and strengthproperties in the frozen, thawed, and thawingstates changes considerably the stress-strain stateand the stability of a slope,2. Slope stability is conditioned by the con-struction period and by the maintenance regime ofthe reservoir. The design value of K, is influencedby several variable force factors dependentupon a) construction cutting of rock thickness,b) changing hydrostatic head, c) unit weight changeof a thawed part of a hillside along with a changeof a depression curve disposition, and d) the dimensionsand conEiguration of the thawing area a ofhillside outline.3. The suggested method of evaluating slopestability, based on numerical calculations of thestress-strain state, is efficient for a greatextenr actual non-homogeneity of slopes (initialand changing with the maintenance of the water powerproject, variable force, thermal effects, and otherfactors.Gulko, E. F.. 1979, Forecast of stress-strain stateof soil fill in its spatial action: Candidatethesis, manuscript, Moscow.Merzljakov, V. P., 1980, Application of the basicthermodynamic relations in description soil ofstrains, Proceedings of the 3rd All-UnionSymposium on soil rheology: Et'evan, p. 273-278.Plotnikov, A. A,, 1978, Temperature regime calculationof permafrost footings, Energeticheskoyestroicelstvo,"no. 8, p. 70-73,Porkhaev, C . V., 1970, Heat interaction of buildingsand structures with permafrost soils:MOSCOW, Nauka.Sedov, L. I., Eglit, M. E., 1962, Non-holonomicmodelling of continuous media by finite strainapplication and some physical and chemicaleffects: Doklady Academii Nauk USSF., v. 142,p. 54-57.Ukhov, S . B;, 1975, Rock footings of water powerstructures: Moscow, Energia.Vakulenko, A. A., 1974, Interaction of micro andmacro models of an elastic-plastic body, Elasticand Plastic Research, vol. 10: Leningrad:Leningrad University, p. 3-37.

A NEW TECHNIQUE FOR DETERMINING TF! STATIC FATIGUELIHIT OF FROZEN GROUNDV. V. Vrachev, I. N. Ivaschenko, and E. P. ShusherinaGeology Department, Koscow State UniversityMoscow, USSRExisting techniques for determining the static fatigue limit (b) of the frozenground are time-consuming and labor-intensive (Vyalov al. et 1966, 1978; Tsytovich1973). The proposed new method can achieve an accelerated determination of thestatic fatigue limit by means of brief tests by gradually increasing on loadingsublimated samples of frozen ground. The physical bases of the method, which hasbeen verified experimentally, are as follows: 1) the static fatigue limit offrozen clay materials depends upon the structural bonding of the mineral frameworkrather than on bonding by ice-cementing; 2) the structure and texture ofthe mineral framework do not vary Considerably during sublimation of the icecreteuntil the ground moisture equals the content of unfrozen water under the samethermodynamic conditions; and 3) the static fatigue limit of sublimated groundapproximates in magnitude its theoretical instantaneous strength b. To determineby the proposed method within limits of accuracy which are acceptable forpractical purposes, it is recommended that one select for analysis samples offrozen clay material with a massive or micro-veined cryogenic texture within thetemperature range of -3 to 20'~.INTRODUCTIONin the field of intensive phase transformationshould not exceed +O.l"C. In addition, to protectThe mechanical properties of frozen ground stemmainly from porous moisture crystallization andicecrete bonding (Tsytovich 1973, Vyalov 1978).Two types of bonding can be distinguished: intrasamplesof frozen ground from erosion it is necessary to keep them hermetically sealed in specializedcases. These factors complicated thepreparation and perfornance of extensive tests;crystalline bonding within the polycrystalic ice- moreover, slight deviations from these requirementsctete and ice-cementing between the ice and mineral causes significant scattering of the experimentalparticles. Both types are of chemical (hydrogenic) data. The most reliable values of can benature, but can vary considerably in their energy obtained when a number of identical ground sauplesdepending upon the chemical affinity between thesurface contacts and the presence of an unfrozenwater film between them. The rheological processesare rested by loads that are different in strength,but constant over time. The firsr sample was testedby rapid loading and its conditional instantaneousof creep, relaxation, and decrease of strength in strength Ro was then determined. The rest of rhetime are associated with the presence of ice in the samples (no less than 6) were tested for creepfrozen ground.effect at various loads less than Ro. Each sampleThe strength and deformability of frozen clay was pushed to failure and the corresponding timeground can also be determined by structural bonding was recorded. The resulting static fatigue curveof the mineral framework caused by molecular and approximates, in particular, the experimentallyion electrostatic interaction of particles and their verified expression:cementation by various cryohydrates. Eliminationof ice by means of sublimation allows evaluation ofR(t) = - the individual role of structural bonding and ice-tincementingin the formation of mechanical propertiesT(1)of frozen ground.The present paper considers the use of ice sub- where 6, T are parameters of the static fatiguelimation for the evaluation of the static fatigue curve and t is the time to destruction. Assuming tlimit lL,, which is a basic engineering parameter to be equal to 100 years, we obtain the staticused in the design of structures with foundations fatigue value, R,,.in frozen ground (Vyalov et al. 1962).The proposed method of accelerated estimationR, is used in different design formulae to pre- of ILL was at the Cryology Division of the Geologicaldict the origin and development of cryogenic pro- Department, Moscow State University. It is based oncesses (Grechischev et al, 1966). Existing methods the study of the process of ice sublimation and ito determine parameters of strength and deform- specific effect upon the compasition, structure,ability require strict observation of the tempera- and mechanical properties of frozen ground.ture regime during the test because of theinstability of the mechanical properties of thefrozen ground. The allowable temperature deviationsIce sublimation is a phase transformation of thfirst type, and is a direct transformation of watermolecules from solid to gas phase (Lykov 1968).

307Taking into consideration experimental data that -1O'C under uniaxial compression by various actingindicate the existence of a thin "quasiliquid"layer of bound water on the surface of the icestresses constant in time (Vyalov et al, 1966).All creep tests were repeated three times.crystals, this sublimation is, in fact, evaporationof unfrozen water and simultaneous enrichment ofits reserves due to melting from the lower ice layerDISCUSSION OF RESULTSbrought about by the thermodynamic balance betweenthe solid and liquid phases (Ershov et 1975). al.Results of the study of the microstructure ofthe frozen clay ground by electron microscope TeslaB5-242 (Rogov and Zabolotskaya 1978) show that the??iETBOD Or TEST PREPARATION ANDPERSORMANCEmineral framework is initially represented byseparate elementary particles of various size (fromclay to sands) and by their aggregates. AggregatesThe research performed included the study of the vary in shape and size from 0.1 to 2 mm. Icecretecomposition and structure of the frozen and sub- was not detected even at 500OX magnification. Therelimatedground by electron and optical microscopy, fore, we can suppose that structural bondingtheand the determination of strength and deformability aggregates is determined mainly by the molecularparameters with consideration of the time factor. and ion electrostatic interaction of mineralSamples of Paleogenic clay (mPgp) having natural particles. Ice inclusions should be consideredand disturbed structure and a moisture content (W), typically cement-like, since they form as the resulton the order of about 32-34%, and a framework of water freezing in the ground pores with negligdensity(Yck) of 1.45 g/cm3 were analyzed. Moreprecise definition of the physico-mechanicalible displacement. As a rule, isometric icecreteinclusions consist of one or, rarely, severalproperties of the clay have been studied in a paper crystals with chaotic orientation of optical axes.by Ershov et al. (1975). Cylindrical samples of The ice inclusion-ground aggregate boundary isground (d = 3.8 cm, h = 8 cm) were frozen at aindistinct, which can be explained by the existencetemperature of -30°C to form massive cryogenic of an unfrozen water film in the gap between them.texture. The experimental subject was selected The type of bonding between the crystals within thedue to the fact that sandy types of disperseice inclusions can be regarded as intercrystalline,grounds (sands, fine sandy loam) with massiveand between the ice and mineral aggregates as icecryogenictexture and clays with veined cryogenic cementation. Intra-aggregate ground porosity (n),texture did not fit the purpose of research because in particular, is another basic element of microduringfrost desiccation they broke down into their structure. The optical method used to study theconstituenc elements or units (Zhestkova et al. surface of a cross-section of clay samples in1972).reflected light revealed the distribution of poresIce has been sublimated -10°C at in the special over 0.02 mm. To estimate the effect of ice subsublimatorsin which air an at optimum velocity of limation upon a given component in the microstruc-10-20 m/sec. was blown over and around it. During ture of frozen ground we derived individual indicesice evaporation the changes in the sample wereof its porosity. General porosity "1 is determinedperiodically monitored by the formulabyPH - PK = v YCk (tiH - w )H.B.(2)where PH is initial sample mass (in grams); PK is where A is density of mineral mass of the groundfinal mass (in grams), V is sample volume (in cm3) ; (2.72 g/cm3) and Y,k is density of solid in g/cm3.Y,k is density of ground framework (in g/cm3); WH Porosity formed in 0.02 mm voids has been calculatedis initial sample moisture (in %); and WH.B. is as a pexcentage ratio between the density of theseunfrozen water content (in %).pores and the total area of the analyzed sample inDesiccation of the samples stopped when moisture its plane section. Pores of this size are the mostof clay W became equivalent to the unfrozen water sensitive to any volume changes of the ground.content for the given temperature of -10°C (WH.B.=Table 1 illustrates data on micro-aggregate7.5%).composition and porosity of frozen and sublimatedThe moisture limit WH.B. is of special considera- clay samples.tion; below this limit volume densification of the Analysis of the structure of the mineral framegroundoccurs, resulting in a considerable increase work in the sublimated clay samples shows thatin strength. After ice sublimation is completed, elimination of ice leads to formation of postthesamples were sealed hermetrically and kept at cryogenic a (inherited) structure and texture in thegiven temperature regime for more regular distribu- ground. There is no significant change in thetion of the moisture within the sample. Homogeneity geometry and average size of the aggregates, ofof samples was verified by nondestructive monitor- their mutual alignment and the degree to which theying of the velocity of acoustical wave propaga- fill in the structural space. The latter agreestions in orthogonal directions (Zykov et al. 1974). well with results (Lykov 1968) on the study of theThe microstructure of frozen and sublimated clay effect of vacuum-sublimation drying on the structuresamples has been studied using a light polarization of capillary porous bodies. Lykov noted that "thismicroscope, MIN-8 (Vrachev and Rogov 1975).drying technique keeps the pores of the materialSimultaneously, the micra-aggregate composition of uncompressed and the structure almost unchanged.the described samples was determined by Kachinsky's Slight shrinkage does occur during elimination ofmethod (1957). Creep tests have been performed at adsorptive bound water." All this allows the sub-

308TABLE 1Composition and Structural Properties of Clay SamplesMicro-aggregate compositionSize of particles (mm)Content of particles (W)Clay"-FrozenSand Silt Clayr0.05 0.005-0.05 S0.00546.2 44.6 - 9.2 1.4533.2 37.3 29.5 1.43yCk (g/cm3) nc n > 0.02 mm46.5 __ -47.4 9.948.2 43.8 8,OSublimated -30.0 38.4 31.61.47 46.0 -1.4646.3 8.1Note: Numerator stands for indices of natural composition of ground,denominator is for destructed ground.cerned we shall consider the behavior of frozen andl, %with complete water saturation occurs throughoutthe intraphase surface of particles, while formationof structural bonding occurs only at sites ofgreatest contact. Resistance to the breakdown ofsuch a porous system as the mineral framework ofthe ground depends upon the bonding strength betweenmicro-aggregates at contacts and upon spatial distributionof these contacts. As far as the differencein the reaction of structural and icecretebonding to external mechanical influences is consublimatedclay samples under conditions of prolongedloading. The origin and behavior of rheologicalprocesses in the frozen ground stems mainlyfrom ice inclusions, i.e. icecrete and ice bands intheir composition. Practically any load can causeFIGURE 1 Creep curves for frozen clay of natural plastic flows in them and a re-orientation of theircomposition; stresses equal to: 1-0.47; 2-1.24; ice crystals, in addition to viscous films of un-3-1.49; 4-2.10; 5-2.48; 6-2.64; 7-2.79; 8- frozen water (Vyalov 1978, Tsytovich 1973). The2.94 MPa.process of deformation of the non-sublimated claysamples over time is typical of frozen ground(Figure 1). The creep curves show three distinct4 %stages when stresses exceed static fatigue limit(O>'R%): 1) non-stable creep with a graduallydecreasing rate of deformation; 2) stable creepwith an approximately constant rate of deformation(i.e. plastic viscous flow); and 3) progressingflow with an increasing rate of deformation.In the case of natural ground the last stageends in breakdown of the sample with the formationof visible fractures. Samples of irregular composit',day Qtion demonstrate plastic deformation with theFIGURE 2 Creep curve8 for sublimated clay of following barrel-line formation. The stable creepnatural composition; stresses equal to: 1-0.1; stage dominates over time. The second and the third2-0.5; 3- 1.27; 4- 1.58; 5- 1.7; 6- 1.78 ma. stages are absent in the presence of small stresses(u

309Frozen32t2.034S2 * 01.4520.34 3.1020.3 1.74iO. 251.44f0.03 3.90k0.2 1.50k0.25Sublimated9.7~0.5 1.45t0.01 2.00i0.1 1.73tO. 0510.2*0.5 1.45f0.01 1 e 35kO.l 1.27S0.05Note: Numerator stands for properties of undisturbed ground, denominatorstands for disturbed ground.after the test began. Deformations developing in the mineral framework, which can be determined bythe initial period are caused by elastic compression short-term tests for the strength of the sublimatecof the ground framework and by a predominantly ground samples.reversible relative shift of mineral particles along If we compare the proposed and existing methodsviscous films of unfrozen water, General creep for determining h5 we note that the first hasdeformation of the frozen ground is 15-20% depending obvious merits. In particular, it reduces teston the effective stress and is mainly plastic time since it allows us to determine the of the(reverse). That of sublimated samples is reduced frozen ground by conducting short-term tests ofto 3-5% with domination of the elastic component.When ground freezes its strength is sharplyincreased due to crystallization of porous watertheir sublimated analogues. Besides, sublimatedsamples are less sensitive to temperature variations,especially beyond the field of intensiveand formation of ice-cementing. This phenomenon is phase transformations (below-5'C).And finally,widely used in civil engineering, for instance,during tunneling or trenchingweak and watertheaccuracy of the test results for sublimatedsamples is higher (k4%) than for frozen samplessaturated ground by means of artificial freezing (k12 to 15%).(Vyalov et al. 1962). Ice-cementing depends onAt the same time, it should be noted that thethe amount of ice and the ground temperature; it is proposed method can be used only to determine theless stable than structural bonding. Ground loadingcauses a shift in the balance between the ice andof clay ground in massive cryogenic structures.The possibility of using this method at temperaunfrozenwater due to a concentration of stresses tures below -1OOC is also debateable because weat particle contacts. Under the influence of thegradient that arises, the unfrozen water, which ishave little knowledge about the rheology of lowtemperaturefrozen ground.replenished by melting ice, shifts to the less tensezone where it refreezes. Simultaneously, the icerecrystallizes and a basal plane reorientation ofCONCLUSIONScrystals occurs parallel to the shift forces.These processes cause a decrease in the frozen 1. To determine the of the frozen clayground's strength when the loading is prolonged. ground of a massive cryogenic structure. the sub-The load for clay samples Q is determined by (I) limated analogues can be used, because the strucandequals 0.45 to 0.5 (Table 2).ture of the mineral framework is not disturbedSublimated clay samples, as compared to frozen during the process of frost drying until CJ,., andsamples, do not demonstrate considerable decrease in its static fatigue limit corresponds to the condistrengthover time; their static fatigue resistance tional instantaneous strength of the sublimatedto compression is 0.85 to 0.9 of the conditional ground.instantaneous strength. of the frozen ground2. The proposed method for determining the FJLand % of the sublimated ground show considerable of frozen ground has certain merits as compared tosimilarity. Such coincidence seems to be regular existing methods. It allows a reduction in testif we assume % as maximal stress at which no defor- time, is not as sensitive to temperature variationsmation of the ground occurs during plastic-viscous (+3"C), and its results have high accuracy.flow or breakdown. A similar conclusion about the 3. Ice sublimation allows for more detailedphysical properties of the of capillary porous investigation into the nature of the strength andbodies was reached by Bykovsky (1954) when hedeformability of frozen ground. In particular, itanalyzed the after-effects of deformation of wood. allows us to determine the individual roles ofIf we treat the frozen ground as an elastic- structural bonding and ice-cementing in the formaplastic-viscousmedium pierced by an elastic spatial tion of their mechanical properties.grid, the system could be destroyed when the stresslimit is surpassed; as a result, further increaseof deformations in the frozen ground is no longerinhibited by its mineral framework. As far asREFERENCESinterground bonding is concerned, this stress limit Bykovsky, V. N., 1954, Definition of static fatiguecorresponds to the value of structural bonding oflimit of the wood by the after-effects deforma-

310tion: Zhurnal tekhnicheskoi fiziki, V. 24,is. 9, p. 1631-1635,Ershov, E. D., Ivaschenko, I. N., et al., 1972,Effect of ice sublimation on physico-mechanicalproperties of frozen rocks, 2 Permafrostresearch, is. 13, Izd. MGU, p. 172-176..Ershov, E. D., Kuchukov, E . Z., Komarov, I. N.,1975, Ice sublimation in dispersed rocks: Izd.MGU, Moscow, p. 27-34.Grechischev, S. E., Chistotinov, L. V., Shur, Yu.L., 1980, Cryogenic physical-geological processsesand their prediction: Moscow, Nedra, p.243-246.Kachinskii, N. A., 1957, Mechanical and microaggregatecomposition of the soil and methodsof its investigation: Izd. AN SSSR, IIoscow,p. 34-36.Osipov, V. I., 1979, Nature of strength and deformabilityproperties of clay rocks: Izd. MGU.Moscow, p. 139.Rogov, V. V., Zabolotskaya, M. I., 1978, Finestructure of frozen rocks with icecrete, i~Problems of cryolithology, is. 7: Izd. MGU.Moscow, p. 169-171.Tsytovich, N. A., 1973, Mechanics of frozen ground:Vyshaya shkola, Moscow, p. 126, 127.Vrachev, V. V., Rogov, V. V., 1975, Frost drying asa technique to investigate the strength natureof the frozen clay ground, & Permafrost research,is. 16: Izd. MGU, p. 230-235.Vyalov, S. S., 1978, Rheological basis for mechanicsof the ground: Moscow, Vyshaya shkola, p.138, 263.Vyalov, S. S., Goroderskii, S. E., et aL., 1966,Parameterization method for creep, staticfatigue limit and compression of the frozenground: Izd. AN SSSR, Moscow, p. 41-65.Vyalov, S. S., Gmoshinskii, V. G., et al., 1962,Strength and creep of the frozen ground andcalculations for ice-soil barrier: Izd. ANSSSR, MOSCOW, p. 144-158.Zhestkova, T. N., Ivaschenko, I. N., et al., 1972,On the dependence of mechanical properties ofthe frozen ground and their cryogene texture,- in permafrost research, is. 13, Izd. MGU, p.166-172,Zykov, A. V., 1968, Theory of drying, Energy, p. 74;Zykov, Yu. D., Baulin, Yu. I., Vrachev, V. V.,1972, Some data on elastic moduli variations inthe frozen clay ground in the result of theirfrost drying, Permafrost research, is. 15,KGU, p. 248-250.

PERMAFROST BENEATH THE ARCTTC SEASL. A. ZhigarevGeography DepartmentMoscow State University, Moscow, USSRFrozen seabed materials are widespread beneath the Arctic seas, thus forming asubmarine cryolithozone. The major part of this submarine cryolithozone consistsof mineralized materials containing water supercooled below O'C, Perennially frozenrocks occur as a continuous belt along both continental and island coasts, and alsoas isolated masses on the open shelf within the limits of the Zyryan-Kargin lacustroalluvialplain. The conditions of formation and survival of the frozen sedimentsbeneath the seabed in the arctic seas are discussed,Cryogenic rocks, which are widespread beneath Carrie d out since the 1930s in connection with portthe Arctic Ocean and its marginal seas and which surveys and prospecting for mineral deposits.are one of the most striking phenomena of the Abroad, investigations into cryogenic rocks, basedArctic, constitute a vast subaqueous cryolitho- on drilling, were carried out I932 in by McLachlanzone. The study of cryogenic rocks in the sea- in the northern part of the Atlantic Ocean on thebed is of both theoretical and practical signif- western coast of the Hudson Bay. Systematicicance. Both Soviet and foreign experience in studies of the subaqueous cryolithozone in thethe economic development of the Arctic shelf show American-Canadian North were commenced only in thethat during design and construction in offshore late '60s in connection with the discovery of oilzones, lack of knowledge about and insufficient and gas deposits in the Beaufort Sea.account of, or disregard of, the characteristicThese studies have revealed patterns of disfeaturesof development of the subaqueous cryo- tribution of cryogenic rocks in the Arctic seas,lithozone and its cryogenic rock constituent can as well as special features of the subaqueouscause no less grave consequences than on drycryolirhozone formation. They allowed evaluationland.of permafrost conditions within a large part ofChanges in cryogenic conditions in the ofl-the water area in the Arctic basin. Such evaluashorezone of the Arctic seas take place withtions were made by Baranov (1958), Grigoryev (1962),hydrotechnical construction, prospecting, and Kudryavtsev and Romanovsky (19751, Are (19761, andespecially the exploitation of mineral and oil- Danilov and Zhigarev (1977). Recent research intogas deposits. An essential change in the cryo- the subaqueous cryolithozone makes it possible togenic-geological copditions is to be expected in essentially clarify the cryogenic conditions inestuarine offshore regions as a result of inter- the Arctic seas.basin diversion of northern rivers, as well as inBut is is to be recalled, first of all, thatshoals of bays and straits as pipeline construction cryogenic racks are divided (Danilov and Zhigarev,progresses.1977) into recent and relict by age, perennial andThe first data on the occurrence of frozen seasonal by existence period, and into frozensediment in the Arctic seabed were obtained 1739 in (negative temperature, containing ice and unfrozenduring the Great Northern Expedition, when P. Kh. water), frosty (negative temperature, containing noLaptev, commander of the naval detachment, observed ice and practically no water), and supercooledsea ice adfreezing to bottom deposits at the north- (negative temperature, containing unfrozen watereastern coast of the Taimyr Peninsula. He suggested but no ice) by physical state.that sea ice in the western part of the Taimyr also The subaqueous cryolithozone develops due toadfreezed to the bottom sediments. Such a phenom- thermodynamic, chemical, and hydrodynamic interenonwas recorded by U. R. Parry in 1819-1820 in action between the atmosphere, the hydrosphere,Viscount Melville Bay (the eastern part of the and the lithosphere. The basic external agentsBeaufort Sea).that determine freezing or thawing of rocks in theLater, data on the subaqueous cryolithozone sea are those of absorbed radiation, turbulent andresulted from the expeditions of Nordensheld, Toll, convective circulation of the water mass, andand Sverdrup, as well as some Soviet expeditions advection of heat by currents, which is determinedfor the exploration and exploitation of the Northern to a considerable degree by the sea depth, theShipping Route. It is to be noted that a particular bottom relief, and the ice cover. The main intercontributionto the study of the special features nal agents are the lithological composition ofof cryogenic rock distribution in the seabed was rocks, humidity, mineralization of deposits, andmade by the Uussian polar expedition headed V. by E. pressure of the overlying water mass and sediments.Toll,The integral expression of the external agents isIn the USSR, systematic studies of the subaqueous the temperature of the bottom sea-water layer, andcryolithozone with the use of boring have been that of the internal agents is the temperature of31 1

312the pore water freezing in the bottom sediments.As has been established earlier (Nolochushkinand Gavrilyev, 1970; Zhigarev and Plakht, 1974),the mean annual temperature of the bottom waterlayer is almost identical to that of the depositsat the base of the layer of zero annual amplitudes.Hence the correlation between the temperatures thatdetermine the external and internal agents indicatesdirectly the possibility of freezing or thawingof the deposits, i.e. the formation of recent(newly formed) frozen rock series, conditions ofconservation of relict perennially frozen rocks,and distribution of seasonally or perenniallysupercooled deposits. Only frosty rocks arecharacterized solely by the mean annual temperatureof the bottom sea-water layer.Existing perennially frozen rocks are found tooccur in all recently emerged localities as wellas in the water areas of the seas, but at depthsnot exceeding the maximum thickness of the fastice. Bottom sediments in the coast-ice areasfreeze deep due to the high heat conductivity ofice and the insignificant thickness of the snowcover. The annual repetition of deep freezingresults in new growths of permafrost. With thesea depth exceeding the mentioned value, recentperennially frozen rocks do not form even near theshore. In all the other areas, the recent frozenrocks encircle the entire offshore zone at thecontinental and island coasts with a belt of varyingwidth. The width of this belt is greatest inthe Laptev Sea (up to 35 km) and in the westernpart of the East Siberian Sea (up to 30-40 km).The temperature of the recent perennially frozenrocks at the depth of the annual variation basewas -ll°C in one of the sections of the Laptev Sea,and their thickness for 35 years of freezingapproximated 60 m, as was estimated in the EastSiberian Sea.The problem of occurrence of relict permafrostin Arctic seas is extremely complicated; it can besolved only on the basis of research into the paleogeographicalconditions of the Late Pleistoceneperiod. These conditions comprise the developmentof transgressions and regressions of the Arcticseas and the sea level during their maximum phases,the relief of the shelf and possible formation ofan ice sheet on it, the thickness of the perenniallyfrozen rocks prior to their becoming subaqueous,the interior heat flow, as well as the abovementionedexternal and-internal agents of freezingand thawing.Relict perennially frozen rocks have undoubtedlysurvived in some comparatively recently abradedareas in the Laptev Sea and in the western part ofthe East Siberian Sea within the bounds of thelacustro-alluvial plain of the Zyryan-Kargin age.The boundary of this plain probably ran at a depthof about 30 m. This is demonstrated by numeroussand fields and banks that are residual outcrops ofthe former continental plain and that do not exceedthat depth in the Arctic seas, and also by the factthat there is little or no subaerial relief overthe entire area of the sand fields and banks.During the period of development of transgressionsof the Arctic seas, as is known, there tookplace thermoabrasional destruction of the shoresbuilt of ice-rich deposits of the Zyryan-Karginlacustro-alluvial plain. The deposits thawed inthe destroyed shore sections as they were submerging.It has been noted (Zhigarev, 1981) thatthe most intensive thawing of frozen sedimentstakes place at sea depths ranging between 2-3 rnand 5-7 m. The mean annual temperatures of Thebottom water layer within this depth range arepositive and can reach relatively high values.The sea takes hundreds, and possibly thousands, ofyears to transgress through this depth range.Therefore, extremely intensive degradation of thefrozen rocks from top and from bottom developsduring this time period. The continuing rise ofthe sea level and bottom sediment washout increasethe depth, lower the mean annual temperatures ofthe bottom water layer, and hence stop the thawingof frozen rock from above and retard the thawingrate from the bottom. Occurrences of relict permafrostare distinguished on the basis of an analysisof sea depths, bottom relief, and the lithologicalcomposition of the bottom sediments. Relict frozenrock series have survived in areas of the completelythermoabraded Semenov, Vasilyev, Figurin, and Diomidislands.' The survival of relict permafrost is also possiblein regions with intensive present-day accumulationsof marine sediments where the sea depthhas decreased to a value equal to the maximumthickness of the fast ice. Thus, for example,highly ice-rich rocks were recorded at a depth offrom 86 m to the borehole face at 100 rn on an inletoffshore bar in the Laptev Sea, with its depth herebeing 1.9-2 to 2.5 m (Zhigarev, 1981). Relictfrozen rock masses can be supposed to occur inregions of extensive sand field distribution overshoals of the seas. It can be assumed, accordingto the mentioned characteristics, that relict frozenrock series are most widespread in the Laptev Sea,bur they also occur in the western part of the EabLSiberian Sea and more rarely in the Kara Sea. Theirthickness can reach hundreds of meters in freshlyabraded areas, but it probably does not exceed tensof meters in regions of old thermo-abrasion withinthe Zyryan-Kargin lacustro-alluvial plain.The recent and relict perennially frozen rocksnear continental and island coasts form original"visors"(overhangs) directed towards the sea wherethey wedge out. Grigoryev (1966) was the first torecord such forms of deposition of perenniallyfrozen rocks. In some gulfs of the Laptev and EastSiberian Seas, we happened to observe doubleIIvisors", . with the upper and lower ones beingcharacteristic of the recent and relict frozenrocks respectively.As is known, the zone of the Arcric seas is amosaic structure consisting of a number of largeupheaved or lowered blocks divided by foldedformations or by wide ruptured belts. The upheavedblocks are built of sedimentary rocks of theSilurian, Devonian, or Carbonic periods. In theeastern sector of the Arctic, these are overlain bythe Cretaceous effusive rocks and by a thin coverof loose deposits, but this cover is locally washedaway completely, and the effusive rocks, undernegative temperatures, are overlain by frost rocks.The latter are widespread in the Kara, Laptev, andEast Siberian seas.The lowered blocks in the western sector of theArctic are built of a series of poorly consolidatedor unconsolidated sediments with a thickness of up

31 3to several kilometers of the Triassic-Quaternary occurrences. Stamukha is an ice hummock (oror Jurassic-Quaternary age, and those in thegrounded ice) of dynamic origin that forms a a5eastern sector are built a of series of Cretaceous-Cenozoic deposits. The occurrence of relict frozenrocks is theoretically possible in lowered blockareas under negative temperatures. However, poreresult of the wind effect and the development ofsea-ice compression pressure forces on shoals,banks, and reefs, with sea depths not exceeding20 m. Usually, floating hummocky ice penetratingwater of loose deposits in the offshore zone of the shallows adfreezes to the bottom sediments, becomesArctic seas, as seen from the studies carried outby the MSU Problem Laboratory for Development ofimmobile, and turns into stamukhas. The latterhave a shape of gently sloping eminences with slopethe North and other organizations, is characterized steepness not greater than 30". In some parts ofby extremely high mineralization of chloride-sodium, the East Siberian Sea, an average of one stamukhasulfate-sodium, or chloride-calcium types, reaching per km* can be observed (Eosbunov et al., 1977).50 to 160 g/kg and penetrating right down to theunderlying bedrock, Under the conditions of suchmineralization and of relatively high negativetemperatures of the bottom deposits (-0.4" to-l.a"C), loose rocks supercooled below 0°C are mostwidespread in the Arctic seas. Perennially super-Their lengths, widths, and heights vary here from50 to 4750 m, 20 to 3500 m, and 2-4 to 20 m,respectively. Occasionally some stamukhas standingnear one another form chains or ramparts and ridgesstretched for several tens of kilometers. No onehas studied the temperature regime of stamukhas.cooled rocks occur in all the Arctic seas, as well There are, however, some temperature data on a perasin the abyssal part of the Arctic Ocean. Theseare absent only in areas where the warm Atlanticand Pacific waters affect the bottom, and in thezones of influence of the major Siberian rivers,ennial ice mass from the section. Cherepanov(Peschansky, 19631, for example, studied the temperatureregime in an 8-m ice mass at SP-6 theStation (North Pole drifting station), The temperawherethe mean annual temperatures of the submarine ture at its base varied during the year from -2.4"Cdeposits are always positive.(June, 1957) to -3.8'C (April, 195&),The recent and relict perennially frozen andperennially supercooled rocks recorded in the Arcticseas are overlain by seasonally frozen and seasonallysupercooled rocks in the offshore zone.Seasonally thawed rocks occur in the emerged areasof the newly formed frozen rock masses. Seasonallysupercooled rocks are rather widely spread in theArctic seas. According to estimations, these aredeposited as a layer up to 4 m thick from zero sealevel to depths of 16-18 m, 14-16 m, and 20-22 m inthe Kara, Laptev, and East Siberian Seas, respectively.Within the above depths, these rocks areabsent only in areas of localization of fast-icemasses (the Northern Land, Yana, and New Siberianmassifs).Seasonally frozen rocks in areas with rapidlygrowing depths extend into the sea for tens orhundreds of meters, while on shoals with depthsnot exceeding the fast-ice thickness they extendfor kilometers or even tens of kilometers. Themaximum thic.kness of seasonally frozen rocks atzero sea level reaches 2 m. The thickness invariablydecreases towards the water. Such rocks,as well as the newly formed frozen rock massesdiscussed above, occur at sea depths not exceeding2.5-3 m. Sections of submarine deposits washed byfresh river underchannel flows in estuaries andestuarine offshore zones are an exception to thisrule, Seasonally frozen rocks in this case canform at greater depths as well. In the autumn-winter period, due to the reduction of the warmflows of the river waters, sea waters supercooledbelow O°C intrude along the deepest sections ofthe rivers. Because the sea waters have negativetemperatures, while the pore water of the poorlypermeable underchannel deposits is fresh, freezing This factor should be given proper attention andof the latter takes place, The extension of the must be taken into account in any kind of economichalocline in the estuaries of individual rivers can development of the vast Polar territory.reach hundreds of kilometers, and most deep-waterand poorly permeable sediments over this entireREFERENCESdistance are seasonally frozen. The depth of theirfreezing, according to estimations, reaches 1 m.A unique characteristic of freezing bottomsediments is observed in regions of stamukhaA rather intensive destruction of stamukhas takesplace in summer in the ice-free water area due tothe effects of heat and wave agents. The greaterthe size of the stamukhas, the slower their destruction.After the stamukhas are destroyed com-pletely, the bottom sediments in places of theirbedding can be found to be nonsaline or even frozen.It is probably just such sediments that were observedby Molochushkin (1973) in the Dm. LaptevStrait of the East Siberian Sea. The very widedistribution of stamukhas in this region is corroboratedby observations carried out during navigationin various years (Khmyznikov, 1937). The existenceof sediments in a frozen state is determined by thetime period of existence of the stamukhas themselves.It can be either seasonal or of 2- to 3-years existence, The areas of such freezing, likethe areas of stamukha occurrences, have no permanentcharacter. The depth of freezing of the bottomsediments in these areas apparently does not exceedseveral tens of centimeters. Hence it follows thatsmall sporadic islands of the original seasonallyfrozen rocks, or pereletoks of frozen ground, occurin the bottoms of the Arctic seas.Seasonally thawing rocks ("osushki", beaches,spits, barriers, bars, etc.) are widespread on theemerged surfaces. Due to the high mineralizationof the pore water, these rocks thaw considerablyearlier and freeze later than the nonsaline deposits.The thickness of seasonally thawed deposits in theregion of zero sea level is equal to the thicknessof the layer of seasonal freezing.Thus, the Arctic seas are characterized by thewide distribution of various cryogenic rocks thatcreate a very comp1,icated cryolithozone structure.Are, F. E., 1976, On the subaqueous cryolithozoneof the Arctic Ocean, & Regional and thermophysicalstudies of frozen rocks in Siberia,

314Yakutsk, Knizhnoe Izdatelstvo, p. 3-26.Baranov, I. Ya., 1958, Some regularities in thedevelopment of perennially frozen rock seriesand in seasonal freezing of soils, & Transactionsof the Academy of Sciences of theU,S.S.R., Series of Geography, no. 2, p. 22-35.Danilov, I. D., and Zhigarev, L. A., 1977, Cryogenicrocks of the Arctic 1 In shelf, Frozenrocks and the snow cover, Moscow, Nauka, p.17-26.Gorbunov, Yu. A., Losev, S. M., and Timokhov, L, A.,1977, Ice drift with stamukhas present, & Thehydrological regime and dynamics of the ArcticOcean, Leningrad, Gidrometeoizdat, p. 79-94.Grigoryev, N. F., 1966, The perennially frozenrocks of the maritime zone of Yakutia, Moscow,Nauka, 123 Q..Grigoryev, N. F., 1962, The role of cryogenicfactors in the formation of the sea coasts inYakutia, & Perennially frozen rocks and theaccompanying phenomena in the territory of theYakutsk A.S.S.B., Moscow, Academy of Sciencesof the U.S.S.R. Publishers.Khmyznikov, P. K., 1937, A description of thenavigations of vessels in the Laptev Sea and inthe western part of the East Siberian Sea,Leningrad, Glavsevmorput Publishers, 180 p,Kudryavtsev, V. A., and Romanovsky, N. N., 1975,The cryolithozone of the shelf of the Polarbasin, & Problems of the geology of the shelf,Moscow, Nauka, p. 60-66.Molochushkin, E. N., 1973, The effect of thermoabrasionon the temperature of perennially frozenrocks in the offshore zone of the Laptev Sea, &The Second International ConferencePermafrost,Papers and Communications, v. 2, RegionalGeocryology, Yakutsk, Knizhnoe Izdatelstvo, p.52-58.Molochushkin, E. N., and Gavrilyev, R. I., 1970,The structure, phase composition, and thermalregime of the rocks constituting the bottom ofthe offshore zone in the Laptev & Sea, TheArctic Ocean and its coasts in the Cenozoic,Leningrad, Gidrometeoizdat, p. 503-508.Peschansky, I. S., 1963, Ice science and ice engin-eering, Leningrad, Morskoi Transport, 345 p.Zhigarev, L. A., 1981, The development of thecryolithozone of the East Siberian and ChukchiSeas in the Pleistocene and Holocene, Thehistory of development of perennially frozenrocks in Eurasia, Moscow, Nauka, p. 181-191.Zhigarev, L. A., and Plakht, 1. R., 1974, Specialfeatures of the structure, distribution, andformation of the subaqueous cryogenic rockseries, in Problems of Cryolithology, v. 4,Moscow, Moscow University Press, p. 115-124.

ofProblemsGeocryologyIIPOGJIEMbIrEOKPIiIOJIOrHMP, 1. W1' nikov, Editol-in-ChiefNauka, Moscow, 1983PREFACEThe present collection contains papers byleading Soviet experts in the field of geocryology,prepared for the Fourth International Conferenceon Permafrost, held in Fairbanks, Alaska,July 1983. "ne collection contains the results ofresearch conducted between 1978 and 1982 in variousareas of permafrost study. Problems of theoretical,experimental, and engineering geocryologyare examined, and principles of new scientifictrends are formulated.This collection combines the results of researchcarried out on general geocryology, cryolithology,the thermal properties of permafrost,rheology, mechanics and engineering geocryology,as wel as on the principles of environmental protectionand the recultivation of landscapes thathave been altered by man and that are found in thevicinity of permafrost,The combination of leading experts in differentareas of geocryology, who describe importantproblems for future research, is of great interestwithin the framermrk of a single collection,The collection opens with a paper by Mel'nikovet al. that, based on a geohistorical analysisof the conditions of development of cryogenicstrata during the Quaternary period, presents zonaland regional principles of the cryogenic transformationof rocks and groundwater in various hydrogeologicalstructures within the USSR. Kudryavtsev'spaper presents an analysis of the thermalbases of geocryology and describes ways to improvegeocryological surveys and to obtain rawdata for forecasting changes in permafrost conditionsand for considering cryolithogenesis as azonal type of lithogenesis. Specific zonal featuresare distinguished in the structure of epicryogenicrock strata, and the spatial correlationbetween types of cryogenesis and the conditions ofunidirectional tectonic development is noted.A number of the papers present results of researchin the area o€ soil mechanics and the constructionof foundations. Tsytovich et al. presenta unique method for forecasting the thermalstress-strain states of soil structures that isbased on the theories of thermoelasticity andthermomechanlcs. The paper by Vyalov et al. presentsnew methods for calculating pile foundationson the basis of two groups of limiting conditionsthat take into consideration the rheological characteristicsof frozen soils. A new approach tothe thermal physics of the foundations of buildingsand structures is described by Khrwtalev.The collection includes papers that are devotedto the study of cryogenic structures and thestructure and characteristics of freezing, frozen,and thawing soils. There are papers describingresearch into the dynamics of the cryolirhozone asit is affected by changes in climate and by humanactivity, the role of thermal abrasion in the developmentof the cryolithozone of the EurasianArctic shelf during the late glacial period, andother problems. Current views on the history ofthe development of permafrost in the USSR are givenby Baulin et al. Gorbunov presents correlatedresults of studies on permafrost in the mountainousregions of Central Asia.Individual problems of environmental protectionand the recultivation of disturbed landscapesare examined in the papers by El'chaninov and Grigoryev.The materials in this collection shed lighton various problems and trends in geocryology and,in some measure, sum up the work that Soviet geocryologistshave conducted in recent years.ABSTRACTSNew trends in ground water study in cryonenic re-gions. Mel'nikov, P.I., Romanovskii, N.N., and_ _Fotiev. S.M.. D. 7-21.Based on a geohistorical analysis of the developmentalconditions of cryogenic strata duringthe Quaternary period, the zonal and regionalcharacteristics of the cryogenic transformation ofrock strata and ground waters in various hydrogeologicalstructures in the USSR are examined andindicated on a map. The characteristics of thecryogenic transformation of the conditions ofwater exchange in different geocryological zonesand hydrogeological structures are evaluated.Particular attention is given to the results ofnew studies of open underwater taliks and icing,which are indicators of ground water dischargefoci. The importance of studying the compositionand mineralization of cryometamorphosed fresh andsalt waters is discussed.Initial assumptions of the thermophysical (geophysical)bases of geocryology.Kudryavtsev, V.A., p. 21-27,A broad geophysical approach, which unitesthe geostrucrural, geographic, geohistorical, andthermophysical approaches, is substantiated forthe study of the frozen zone of the Earth's315

316crust. It involves the use of a large variety ofmethods to study the qualitative and quantitativerelationships between the parameters of seasonallyand perennially frozen strata, as well as theprinciples of formation of the composition and thecryogenic structure of permafrost, cryogenic processesand phenomena with the constituents of thegeological and geographical environment, examinedwithin a geohistorical framework. The permafrostsurvey is the basic method of obtaining the initialinformation.Geocryological conditions of Yakutiya in relationto the construction of trunk pipelines.Mel'nikov, P.I., and Grave, N.A., p. 28-35.The paper presents a brief physico-geographicaldescription of Yakutiya. Geocryological regionsare described, and the territory is schematicallydivided into regions according to the resistanceof the surface to technological activities.Data are presented of observations of thedevelopment of surface damage al-ong the route of aburied pipeline.Cryolithogenesis as a zonal type of lithogenesis.PODOV. A.1.. De 35-43.. The geneial position of cryolithogenesiswithin the lithogenesis system is determined.Cryolithogenesis is examined as a phenomenon ofdiagenesis and hypergenesis (cryodiagenesis andcryohypergeneais) that is characteristic of thethermodynamic situation of the zones of constantcooling of the Earth, Specific zonal featuresare distinguished in the structure of epicryogenicrock strata that are characteristic of northernEurasia (as an example of the zonal nature ofcryolithogenesis). The spatial relationships oftypes of cryolithogenesis to the conditions ofequidirectional tectonic development are noted.Predicting the thermal stress-strain condition ofearthworks by the finite element method.Tsytovich, N.A., Kronik, Pa.A., Gavrilov, A.N.,and Demin, 1.1. , p. 44-56.How to formulate and obtain an approximatesolution to the problem of predicting the thermalstress-strain state of earthworks that are constructedunder severe climatic conditions is examined.A unified method is developed for predictingthe thermal and stress-strain states ofearthworks on the basis of the theories of thermoelasticityand thermomechanics in the formulationof a disconnected plane problem. As an example,the thermal stress-strain state of a test embankmentconstructed of macroelastic soil is calculatedby the finite element method with the aid of acomputer. The results of the computations arecompared with two years of field observations ofthe test embankment.Settlement and bearing capacity of pile foundationson permafrost. Vyalov, S.S., Slepak, M.E. ,and Tikhomirov, S.M., p. 57-67.Methods are presented for designing pilefoundations on the basis of two groups of limitingconditions. In contrast to traditional nrethods,the methods described take into account the rheologicalcharacteristics of frozen soils and makeit possible to carry out pile computations underboth constant and variable external loads and temperatures.Examples are presented to illustratethe new methods.Foundations on permafrost that thaws while thebuildinR or structure is in use. Kolesov, A.A.,p. 68-75.Effective methods are examined for the constructionof foundations on permafrost for industrialand civil uses. Recommendations are givenfor the design of foundations, how to lay them,and how to prepare the ground prior to construction.Ventilated solid foundations on fill,Kutvitskaya, N.B., and Dashkov, A.G., p. 76-82.Design solutions are examined for solid foundationsof the slab, strip, and column types,which combine bearing and cooling functions. Onthe basis of experimental and theoretical research,a solution is given to the problem of theinteraction between buildings on ventilated solidfoundations and the permafrost. Examples are presentedof design solutions and of actual construction.Calculating the thawing depth of multilayer coveringson permafrost ,includinE a highly efficientlayer of thermal insulation. Ivanov, V.N.,Merzlyakov, V.P., and Plotnikov, A.A., p. 82-89.An analytical method is proposed for calculatingStefan-type thermal conductivity in multilayerconstructions that include an efficient layerof thermal insulation as used in permafrostcoverings. The solution is reduced to a series ofrecurrence formulas that are used to write a computerprogram in Fortran IV. The results of thecalculations are compared with field observations.Fundamentals of the thermorheology of cryogenicsoils. Grechishchev, S.E., p. 90-100.The thermorheology of cryogenic soils (TCS)is defined. A brief overview is presented of certainscientific trends in the physics and mechanicsof cryogenic soils from the point of view ofthe applicability of the obtained results to thedevelopment of the principles of TCS, The thermodynamicand mechanical conditions at the phaseboundaries in waterlogged so118 are presented, asis a theoretical model of cryogenic heaving. Severalknown cryogenic soil phenomena are explainedon the basis of the proposed theory.Shear resistance of permafrost during thawing.Shusherina, E.P., Maksimyak, R.V., and Martynova,G.P., 100-108.Results of experimental studies of the shearresistance of permafrost during thawing are examined.The research was carried out on undisturbednatural soils of various origins, charac-

317terized by different structural and textural features,moisture contents, and compositions of theskeleton. The shear resistance of thawed soil at.the thawing boundary as a function of these factorsis presented, as is the relation of the sizeof the normal load and the angle of inclination ofthe ice layers to the shear plane.The flow of frozen soils on rock slopes.Sadov-skii, A.V. , and Bondarenko, G. I. , p. 108-113.The mechanism of the shear deformation offrozen soil during flow over a rock slope wasstudied. The shear testing of samples of soilthat are adfrozen to rock slopes and observationsof the deformation of frozen soils during dumpingon rock slopes established the existence of twoflow zones in soils that are flowing down a rockchannel: a contact layer and a layer that is locatedhigher in the soil. The rate of flow at thesoil surface is equal to the sum of the rates offlow of these layers. The rates of flow that arecalculated using the suggested formulas are ingood agreement with observed rates of creep offrozen soil dumps.Physicochemical aspects of the creation of manmadeice structures using seawater. Savel'ev,B.A., Gagarin, V.E., Zykov, Yu.D., Latalin, LA.,Rozhdestvenskii, N.Yu., and Chervinskaya, O.P.,p. 113-118.The creation of man-made ice structures isexamined from three points of view: the quality ofthe artificial ice, the adfreezing of the structureto the bottom of the reservoir, and the durabilityof the structure. On the basis of experimentsthat used structural analysis and geophysicalmethods, the advantage is shown of creatingice structures and of securing them to the bottomby freezing ice within a volume of water. Thequestion of the thermal regime of a man-made icestructure in shallcw water is examined.Elastic and electrical properties of ice-richsoils and ice. Zykov, Yu.D., Rozhdestvenskii,N.Yu., and Chervinskaya, O.P., p. 118-127.To successfully use geophysical methods tostudy ice-rich soils and ice, it is necessary tostudy their properties, beginning with their elasticand electrical properties. Experimental dataare examined on specific electrical resistancesand speeds of elastic waves in ice of varying compositionand structure, as well as the dependenceof these parameters, as measured on model sampleswith layered cryogenic structure, on the ice content.Significant anisotropy was observed, andits dependence on various factors was studied.The results are compared with calculations. Thepossibility of evaluating the properties of iceand ice-rich soils by electrical and acousticmeasurements Is demonstrated.Thermophysical problems of permafrost engineer-&. Khrustalev, L.N., p. 127-136.Practical problems that currently confrontresearchers in the construction of foundations onpermafrost are examined. The author discusses theproblem of thermal interaction between erectedstructures and permafrost, foundation cooling usingnatural cold with the aid of various types ofself-regulating cooling installations, and evaluatingfoundation reliability to arrive at a seientificallyvalid way of choosing the method forbuilding a foundation. The most effective approachesand methods of solving these problemsare indicated.Significance of soil complex changes on the permafrosttemperature regime. Shur, Yu.L.,Shvetsov, P. F., Slavin-Borovskii, V.R.,Moskalenko, N.G., and Malevskii-Malevich, S,P,,p. 136-143.The effects of weathering, soil formation,and vegetation on the temperature regime of permafrostare examined. Changes in mean annual temperatureare evaluated in connection with a directedchange in the properties of the seasonallythawing layer. Temporary variability of the componentsof the temperature balance is studied.Formation of cryopenic structures during; eplgeneticand syngenetic freezing of dispersed soils.Ershov, E.D., p. 143-152.The mechanism of the formation, development,and transformation of various types of cryogenicstructures is examined on the basis of heat-massexchange and physicochemical and physicomechanicalprocesses that occur in freezing and frozensoils. The formation of migration ice and segregatedice layers in permafrost, which have frozenepigenetically and syngenetically, is examined.Investigation of the main factors and the mchanismof the cryogenic transformation of minerals.Konishchev, V.N., Kolesnikov, S.F., and Rogov,V.V., p. 152-157.A theoretical model of the cryogenic stabilityof particles of various sizes of the mainsoil-forming minerals is examined on the basis ofnotions about the protective role of unfrozenwater. The cryogenic breakdown of quartz, feldspars,hornblendes, pyroxenes, and ores is modeledin the laboratory. Tables are given of the cryogenicstability of minerals at various temperaturesand moisture contents.Permafrost facies structure of modern alluvial depositsof plain rivers in the eastern Subarctic.Rosenbaum, G.E., p. 158-161.The facies structure of modern alluvial depositsof plain rivers of the eastern Subarctic isexamined. Riparian and inner-floodplain faciesare distinguished in the structure of the riverplain alluvium. Subfacies are distinguished withineach facies, depending on the nature of the developmentof the polygonal relief and the iceveins in different sections of the plain surface.Superimposed river plains are distinguished inwhose cross sections the facies of the innerfloodplain is underlain not by channel alluviumbut rather by deposits of an alas complex.

Cryolithogenic deposits and their permafrost-formationcomplexes. Katasonov, E.M., p. 162-169.Deposits that form near permfrost are examined.Depending on the conditions of accumulationand freezing, they are classified as permafrostformation complexes - strata that are distinguishedby the types of facies and their contentand distribution of ground ice. Special attentionis devoted to ice complexes. Standardsections are presented.Cryolithogenic consequences of non-uniditnensionalfreezing of soil. Zhestkova, T.N., p. 169-177.The freezing of soils under two- and threedimensionalconditions was investigated. The relationshipbetween the cryogenic structure and thethermal field of the frozen soil is established.The existence of horizontal heaving, which may attainsignificant proportions under non-unidimensionalsoil freezing conditions, is proven.Paleogeographic reconstructions of the Pleistocenebased on the thickness and structure of perma-- frost. Baulin, V.V., and Chekhovskii, A.L., p.177-184.Problems of paleoclimatic reconstructionsbased on the analysis of the distribution of thickpermafrost are examined. It is concluded that thethickness and structure of permafrost can serve asindicators of changing heat exchange conditions atthe Earth's surface.Cryolithozone dynamics as related to climaticchanges and anthropogenic influences. Balobaev,V.T. , and Pavlov, A.V., p. 184-194.An analysis is presented of climatic and geocryologicalchanges effected by the natural globalcycle (which has a period of several thousandyears) and influenced by anthropogenic changes inthe composition of the atmosphere, for the nextcentury, and, as affected by local technology, inthe short term. An attempt is made to evaluatethe quantitative limits of possible transformationsof the CKyOlithOZOne, its thermal regime,thickness, and local development.The role of thermal abrasion in the developrent ofthe cryolithozone of the Arctic Shelf of Eurasiaduring the late- and post-glacial period. Are,F.E., .. p* 195-201.Based on studies of the deterioration of theshores of arctic seas and on paleogeographic concepts,the role of thermal abrasion in the developmentof the subaqueous cryolithozone of the ArcticShelf of Eurasia during the late- and postglacialperiod is presented. In the Soviet Arctic,six regions are distinguished that differwith regard to the development of thermal abrasion.It is shown that in the East Siberian regionthe rise in the sea level during the postglacialtransgression was responsible for a rapidrate of change in the position of the shoreline.During this process thermal abrasion broke up theupper layers of the continental glacial deposits,which then came to be in a subaqueous position.Methodological principles of the evaluation, proRnosia,and mapping of natural complexes with varyingresistances to thermal subsidence. Zhigarev,L.A., and Parmzina, 0. Yu., p. 201-206.The principles of evaluating and forecastingthermal subsidence in natural complexes are described.Methods are proposed for mapping suchcomplexes, which have varying resistance to thermalsubsidence.The effects of mining on the environment and methodsfor alleviating them. El'chaninov, LA., p.207-214.Mining for minerals causes the removal fromthe natural environment and the dumping into theenvironment of a series of components. An evaluationis presented of the subsystem of the technologicalcycle and the degree to which they affectthe environrcent. Information is given on developedtechnological procedures that contribute tothe elimination or attenuation of the harmfuleffects of mining on the environment.The Central Asia permafrost region. Gorbunov,A*P*, p* 214-222.Data about the cryolithozone and the cryogenicrelief of the mountains of Central Asia arecorrelated. The extent of the area of permafrostin the region is estimated to be 2.09 million km2,the volume of the cryolithozone is 160,000 Ian3 andthe volume of ground ice is 9,000 km3. The upperpermafrost boundary in the northern part of theregion is at 2200 m above sea level, and in thesouth at 5000 m above sea level.History of the development of permafrost in theUSSR, Baulin, V.V., Velichko, A.A., and Danilova,N.S., p. 222-229.A brief paleogeographical scheme is proposedfor the formation of permafrost throughout the en-* tire territory of the Soviet Union for the mainstage of the Quaternary. The Upper Pleistoceneand the Holocene, which are subdivided into stagesof multi-directional permafrost dynamics, are coveredin the greatest detail. All of the reconstructionsare made on the basis of an analysis ofthe cryogenic structure of the permafrost, ofwedge ice, and of associated pseudomorphosis, aswell as the thickness of the permfrost. Specialfeatures of the development of permafrost in largeregions of the USSR, such as the European plainand western Siberia, are examined.The use of cryochedcal data in the study of theoripin of ground ice deposits. Anisimova, N.P.,and Kritzuk, L.N., p. 230-239.The physicochemical processes that determinethe chemical composition of ground ice depositsthat were formed in various ways are examined.The comprehensive study of the unique deposit ofground ice in the valley of the Se-Yakha River onthe Yamal Peninsula is presented as an example.It is concluded that it originated underground,and that the injection mechanism o€ formationplayed a role.

319Suprapermafrost water of the cryolithozone: Itsclassification and description. Shepelev, V.V.,p. 239-244.The characteristics of the suprapermafrostwaters of the cryolithoeone and schemes for theirclassification are examined. A brief descriptionis given of the individual subtypes, classes, subclasses,and varieties suprapermafrost water, distinguishedaccording to their relationships to thevarious cryogenic confining strata, the degree offreezing, their conditions of occurrence, hydraulicproperties, and temperature. The great importanceis pointed out of suprapermafrost water inthe development of many permafrost processes andphenomena, as well as in changes in the permafrost-hydrogeologicalcircumstances that are dueto man's activities.depth at which soil strata that contain ice occurin the cryolithosphere, as are results of the geomorphologicalstudy of various permafrost indicatorsin the relief of Mars.Autoregeneration (optimization) of disturbed surfaceconditions in northern West Siberia.Grigoryev, N.F., p. 256-263.Examples are presented of relatively rapid(3-4 years) arrest of thermokarst during its initialstages, when it is caused by the disturbanceof the vegetative cover of tundra on ice-richsoil. The summer thawing layer is observed to dryout gradually after the removal of the vegetativecover, which helps to improve the stability of thesurface.Thermodynamic criteria of the stability of thesoil complex in the Subarctic.Shvetsov, P.F., p. 245-247.The expenditure of energy for cryogenic processesis evaluated on the basis of heat storagedata. The thermodynanic and mechanical stabilityof subarctic soil complexes is examined.The cryolithosphere of Mars and cryogenic phenonrena on its surface. Kurmin, R.O., p. 247-255.Structural features of the olanetarv ... oermafrostmantle of Mars' crust (cryolithosphere) andthe possible distribution within it of stablephases of water and carbon dioxide are examined.Data are presented about the determination of thePermafrost surveys and forecasting of chanRes inpermafrost conditions during economic developmentof permafrost regions. Kudryavtsev, V.A., p. 264-269.The existing requirements for permafrost surveys,as stated in Departmental and All-Unionstandards and technical regulations for surveys,are inadequate for producing scientifically substantiatedforecasts of permafrost conditions duringthe construction and use of structures in thepermafrost zone. Recommendations are presentedfor conducting permafrost surveys in such a way asto make it possible to produce a geocryologicalforecast, and measures are proposed that will ensurethe stability of structures and of the environment.

Other ContributionsWATER FLOWS INDUCED BY THERMAL GRADIENTSD. Blanchard and M. FrhondLaboratoire Central des Ponts et Chausse'es58 Blvd. LeFebvre, 75732 Paris, FranceWater flows are important in soil freezing.At the frost line (O°C isotherm) which separatesthe frozen soil from the unfrozen soil a large depression,the cryogenic suction, draws in a largemount of water, which freezes. We describe amacroscopic model of thermal gradients and waterflows, including the cryogenic suction. The modelis based on the deformability of the soil consideredas a porous medium and the existence of unfrozenwater in the frozen soil. It uses the conservativelaws (Fourier's law, Darcy's law, unfrozenwater content versus temperature in the frozensoil). Its outputs are the temperature and hydraulicpotential functions of space and time. Atwo-dimensional computer program is available.THE NATURE AND DISTRIBUTION OF SHALLW SUBSEAACOUSTIC PERMAFROSTON THE CANADIAN BEAUFORT CONTINENTAL SHELFscale, shallw AET is laterally and verticallyvariable and discontinuous. East of the 135' meridian,the distribution is less well defined becauseof the marginal nature of the ice bonding.The distribution is closely related to thesurficial geology. The shelf is overlain with athin veneer of fine-grained marine deposits (unitA) that overlie or grade downward into a transgressivesequence of interbedded fine- to mediumgrainedsediments (unit B). These two units unconformablyoverlie older pre-Holocene sediments(unit C) of possible reworked fluvial-deltaic origin.The APF is primarily confined co unit C (althoughsome ice content has been observed in theoverlying units). Depth to the APF may vary from0 m to 50 m below the unconformity. In someareas, the top of the APF ia found to mirror theunconformity surface.FROST-HEAVED STRUCTURES IN BEDROCK: A VALUABLEPERMAFROST INDICATORJ . C.DionneDgpartement de Ggographie, Universitd Lava1Quebec City, QuGbec, Canada GlK 7P4S.M. BlascoFrost-heaved structures in bedrock are peri-Geological Survey of Canadaglacial features produced by the vertical dis-Bedford Institute of Oceanography, P.O.Box 1006 placement of bedrock fragments. Blocks, frost-Dartmouth, Nova Scotia, Canada B24 4A2wedged from bare bedrock along joints, are raisedM.J. O'COnnorabove the general surface by frost processes.They are common and exclusive to permafrost regions,and are considered by French as featuresM.J. O'ConnOr and Associates Limitedrepresentative of very active periglacial regions.101-4712, 13th StreetAlthough they were mentioned long ago in theCalgary, Alberta, Canada T2E 6F1Literature by Tyrrell, they have been describedand studied in some detail only recently by Bournbrias,Payette, Dyke, and Dionne. Among the var-The correlation of high resolution analog re-ious features reported, isolated heaved blocksflection seismic profiles with shallow and deep(monoliths) and conical mounds are the most comboreholedata has led to the identification ofmon. Their existence, to our knowledge, is reseveraltypes of shallow acoustic permafrost (APPF) stricted to the Northern Hemisphere: Canada,to depths of 100 m below seabed, including discon- Greenland and Spitsbergen. Numerous sites occurtinuous hummocky APF, continuous APF, stratigraph- in subarctic Qugbec, between Latitudes 51"45' andically controlled APF, APF lensing, and possibly 60"20'N, and in subarctic Canada between latitudesmassive APF associated with offshore pingo-like58"30' and 66'10'N.features. The occurrence of shallow APF has beenThey develop in various lithologies: basalt,mapped over the shelf from the coast to the 70-m diabase, andesite, gabbro, granite, gneiss, crysisobathand from Baillie Island to the easterntalline schisLs, and occasionally in sedimentaryedge of the Mackenzie Trough. On a regionalrocks such as sandstone and quartzite. However,This section contains non-Soviet abstracts and papers that were not available at the time of printing ofeither the Abstract and Program volume or the first Proceedings volume.321

322most features are in volcanic, igneous and metamorphicrock with well-developed system ofjoints.Single heaved blocks from 50 to 200 cm longare often raised as much as 150 cm above the surroundingsurface. Conical mounds made of severalblocks (up to 15 fragments) are commonly 3 to 10 min diameter, and a central depression (crater)characterizes a few structures. Most heavedblocks exhibit weathered and lichen-covered sidesexcept at their bases where freshly exposed surfacesindicate recent heaving. As already mentioned,these features result from frost action,particularly frost wedging and heaving due topressure of ice in vertical, oblique and horizontaljoints.Frost-heaved features in bedrock are all locatedin the permafrost zone. The southernmostoccurrence is at the summit of the Groulx Mountains,QuBbec (51'45'N), near the southern limitof the discontinuous permafrost zone. The meanannual air temperature in the area consideredranges from -4' to -9'C. Although snow depth isnot known for each locality, most sites consist ofbare, well-exposed bedrock surfaces which arewind-blown during the winter. Consequently, athin snow cover is common to the environment.Dating heaved structures is a difficult problem.Hcwever, recent heaving is usually evidencedby lichen-free sides at the base of heaved blocks.The occurrence of several structures in a localityindicates primarily that the conditions requiredfor their development do or did exist; the structuresmay have developed in a relatively shorttime (a few decades) as well as over many centuries.Thus, further studies are needed to documentthe time required for the development ofheaved features in bedrock and to determine theirage in a given locality.Based on their geographical distribution, onclimatic data, and on the occurrence of permafrostat almost every site, it is suggested that heavedfeatures in bedrock could be considered a valuableindicator of permafrost. If found outside thepermafrost regions today, relict heaved featureswill indicate former permafrost conditions.ciation in latest Pleistocene time; most have uppersurfaces which first stabilized by the earlyHolocene. They range from 3-km-long, tongueshapedlobes that are cored by glacial ice andheaded by reactivated (Neoglacial) cirque glaciersand late Holocene moraines to smaller lobate masses15 to 150 m in length lying beyond taluscones. They appear best developed below resistantridges with large exposures of shale, siltstone,and phyllite; their talus enhances insulation ofsubsurface ice. All rock glaciers occur withinthe zone of continuous permafrost at altitudesfrom 900 to 2,000 m. About 75% of the rock glaciersand almost all of the active form occurnorth of the Continental Divide, demonstratingthe climatic significance of this east-west trendingdivide. Gctive tongue-shaped rock glaciershave a strong N to NE orientation pattern. Bowever,lobate form face all directions, demonstratinginsensitivity to insolation and perhaps alower ice content relative to debris. Both formoccur 50 to 100 m higher on south-facing slopesthan on northerly slopes. No correlation wa6found between solar energy received at a rock glacierand the rock glacier's present state of activiKy.Little correlation also exists betweenthe activity state and a) bedrock, b) overallslope, c) orientation, or d) latitude and altitudenorth of the Continental Divide. Whether or not arock glacier is active appears to depend most uponthe availability of debris from headward cliffs.ACTIVE LAYER STUDIES IN NORTHERN QUdBEC: TOWARDS APREDICTIVE MODELS.T.Gray and J. PoitevinDgpartement de Gbographie, Universit4 de MontrCalMontrbal, QuBbec, Canada H3C 357J. PilonEarth Physics BranchDepartrnent of Energy, Mines, and Resources,Ottawa, Ontario, Canada KIA 043ROCK GLACIERS OF THE EAST CENTRAL BROOKS RANGE,ALASKAJ.M.EllisGulf Oil Exploration and ProductionP.O. Box 37048Houston, Texas 77236, USAP.E.Calki nCo.Dept. of Geological Sciences, State UniversityNew York, Buffalo, NY 14226, USAM.P.BruenHarza Engineering Company, 203 W. 15th AvenueAnchorage, Alaska 99501, USARock glaciers here were largely formed by increasedmass wasting associated with valley degla-ofField studies recently conducted on the west coastof Ungava Bay, in the southern part of the contin-UOUE permafrost zone, have permitted the establishmentof the pattern of active-layer developmentfor six different geomorphological and vegetationalterrain types. All study sites were situatedon horizontal surfaces free from local topographicinfluences in order to permit the explanationof thaw progression in term of the earthmaterials, moisture content, and vegetation coverthat characterize each terrain type. Therm1 propertiesfor organic and mineral soil and for bedrockwere calculated from field data on texture,bulk density, and moisture content of the earthmaterials at the sites, and were used to explainthaw-layer development for each terrain type. Alinear relationship was established for each groupof sites between the logarithmic transformation ofthaw penetration and an atmospheric thawing indexobtained through interpolations of air temperaturedata from the two closest meteorological stations--Kwjjuaq (Fort Chimo) and Koartaq (Cape Hope's

323Advance). This relationship was then used in apredictive sense to establish, first, the depth ofthe active layer at the end of the thaw season foreach terrain type, and second, variations in active-layerdepths in the region over a 20-yeartime period. Probable spatial variations of activeLayers for extreme climatic variations in theUngava Peninsula are also briefly presented.THE INFLUENCE OF CLAY-SIZED PARTICLES ON SEISMICVELOCITYFOR CANADIAN ARCTIC PERMAFROST*M.S.KingLawrence Berkeley Laboratory andUniversity of CaliforniaBerkeley, California 94720, USASeismic wave velocities have been masured on37 unconsolidated permafrost samples as a functionof temperature in the range -16' to +5'C. Thesamples, taken from a number of locations in theCanadian Arctic Islands, the Beaufort Sea and theMackenzie River, were tightly sealed imlnediatelyupon recovery in several layers of polyethylenefilm and maintained in their frozen state duringstorage, specinen preparation, and until they weretested under controlled environmental conditions.During testing, the specimens were subjected to aconstant hydrostatic confining stress of 0.35 MPa(50 psi) under drained conditions. At no stagewas a deviatoric stress applied to the permafrostspecimens. The fraction of clay-sized particlesin the test specimens varied from almost zero toapproximately 65%. At temperatures below -2'C thecompressional-wave velocity was observed to -be astrong function of the fraction of clay-sized particles,but only a weak function of porosity. Attemperatures above O°C the compressional-wave velocitywas observed to be a function only of porosity,with virtually no dependence upon the fractionof clay-sized particles. Calculation of thefractional ice content of the permafrost porespace from the Kuster and Toks6z theory showedthat for a given fraction of clay-sized particlesthe ice content increases with an increase in porosity.It is concluded that the compressionalwavevelocity for unconsolidated permfrost from theCanadian Arctic is a function of the water-filledporosity, irrespective of the original porosity,clay content, or temperature.PERIGLACIAL DUNE FORMATION AND NIVEO-EOLIANFEATURES AS EXEMPLIFIED IN THEKOBUK SAND DUNES, ALASKAE.A.KosterPhysical Geography and Soil Science LaboratoryUniversity of AmsterdamAmterdam, The Netherlands*Full paper subsequently published in CanadianJournal of Earth Sciences, vol. 21, p. 19-24,1984.J. P. GallowayU.S. Geological Survey, 345 Middlefield RoadMenlo Park, California 94025, USAActive dune building in the Nogahabara SandDunes (approximately 44 km2) in the Koyukuk Flatsand in the Great gnd Little Kobuk Sand Dunes (approximately64 km ) in the central Kobuk Rivervalley is being studied to compare it with paleodunebuilding in the well-known Weichselian inlanddune and cover sand regions of Western Europe.The active dune fields in the Kobuk River valleyconsist primarily of large parabolic and transverseridges, indicating primary wind directionsfrom the east and southeast. During summer monthssecondary slip faces on the dunes develop due towesterly winds. Wavy transverse ridges have beendeformed into barchan-like dunes. Radiocarbondates (approximately 24,000 B.P.) of sandy peatand organic mud layers underneath the dune sandsindicate a late-Wisconsin age.Distinct stabilized, canoe-shaped dunes resemblethe "Cree Lake-type dune ridges" which occurin northern Saskatchewan. They have beenformed by southeasterly paleowinds of uniform directionby elongation of primary parabolic dunes.Recent analogues are found opposite the mouth ofthe Akillik and Hunt Rivers.In early summer annual denivation features,several meters high, develop in the steep westward-facingslip faces of the large transversedunes. Sand layers incorporated in the snm indicateniveo-eolian deposition during winter, relatedto a discontinuous snow cover. Hummocky topographywith a completely cracked, moist sand surfacerapidly develops. During the course of summerthese features gradually disappear and asmooth slip face is reestablished.THAW PENETRATION AND THAW SETTLEMENT STUDIESASSOCIATEDWITH THE KIRUNA TO NARVIK ROAD, SWEDENS. KnutssonUniversity of Lulei, S-951 87 Lulei, SwedenA permafrost study has been undertaken on therecently built road between the towns of Kiruna,Sweden, and Narvik, Norway. The road crosses anarea with discontinuous permafrost (68'15'N) wherean environmental engineering study was initiatedduring autumn of 1979.Eight holes were drilled to maximum depths of11 m. Four of these were located outside the roadin the undisturbed permafrost and four within theroad in a cross section perpendicular to the roadline.Temperature gauges were Installed in thedrill holes at vertical distances of 0.5 m, Measurementsof the temperatures are taken approximatelyonce a month, and the measurements fromthree years of data-logging have been analyzed.The discontinuous permafrost is warm, -1°C at6-8 m depth, and the depth of seasonal thaw pene-

324tration (active layer) in the undisturbed areasadjacent to the road is on the order of 0.5-1.0m. Beneath the road the seasonal thaw penetratesabout 2.5 m. The difference is explained by thedark colour of the bitumen top cover and of therelatively coarse road material, with its relativelyhigh thermal conductivity during surnmertime.The permanently frozen soil materials rangefrom rock to ice-rich, fine-grained silts with atop layer of peat.The core from the undisturbed area is geologicallydescribed and the amount of ice and thicknessof ice lenses have been measured by means ofX-ray technique. This technique seem to be auseful, easy and non-destructive tool for ice-contentmeasurments in cores of frozen soil.In addition to the temperature measurements,settlement of the road has been observed as well.This shows gradually increasing settlements, whichare due to the thawing of the underlying permafrost.The observed settlements are compared tothose predicted. The predictions are based onthaw-consolidation tests performed in the laboratory,and these are described as well. Reasonableagreement between the observed and predicted settlemntsis obtained.THE EFFECTS OF COAL DUST ON SURFACE ALBEDO ANDTHAW DEPTH IN NORTHERN ALASKAJ.S. Makihara(formerly) Geography DepartmentPennsylvania State UniversityState College, Pennsylvania 16801, USAThe effects of coal dust on surface albedoand thaw depth in arctic Alaska were studied viafield data acquisition and analysis and computersimulation modeling. Field research was conductedduring summer 1981 in the vicinity of PrudhoeBay. Coal dust reduced albedo by 25 to 90 percent.Apart from a higher rate of thaw exhibitedon cqal-dusted plots compared to control plots inJuly, the short-term effects of coal dust were notapparently significant in the field data due tothe short period and spatial extent of observation,and natural variability in thaw and soilthermal regims. In determining long-term effects,computer simulations of one-dimensionalheat conduction revealed deeper maximum thaws upto 52.4 cm, 20 percent over the undisturbed condition,and especially a higher thaw rate in thefirst part of the summer on disturbed plots ascompared to control plots. Given comparableparameters, winter-only impact cases producedgreater thaw depths than summer-only impactcases. Dusting in winter produces prematurespring meltout and consequently deeper thaw; anypotential coal mining activities should be restrictedin April and May. 'Ihe mdel assumes thatdust does not affect vegetation mortality. Inactuality, dust can reasonably be assumed to damagevegetation with subsequent enhanced thermalimpact. Future research should take into accountthe effect of vegetation mortality on surface albedo.PALEO-CLIMATIC RECONSTRUCTION FROM MEASUREDTEMPERATURESIN BOREHOLES IN NORTHERN QUEBECJ.A. Pilon, A.S. Judge and A.E. TaylorEarth Physics BranchDepartment of Energy, Mines and ResourcesOttawa, Ontario, Canada K1A 043J.T.Gray and J. PoitevinDdpartement de Gdographie,Universltd de MontrealQuPbec City, QuPbec, Canada H3C 357B. LauriolUniversity of OttawaOttawa, Ontario, Canada K1A bN5The analysis of deep borehole temperature gradientscan assist in the reconstruction of formerclimates at the ground surface. In this report,emphasis is on the modelling process itself, butsome results are presented in the context of theauthors' geothermal studies in northern Quebec.The modelling process begins with the acquisitionof temperature profiles from one or several boreholesonce the disturbance due to drilling hasdissipated. The drill-hole temperature profileintegrates the geothermal heat flux from deep inthe crust and a number of largely near-surfacemodifying effects. The latter, which create departuresfrom the constancy of the heat flw profilewith depth, reflect the role of I) varyingthermal conductivity in an anisotropic medium, 2)spatial topographic and microclimatic irregularitiesaround the collar of the borehole, 3) watermovement in fractures and joints, and 4) temporalfluctuations in ground surface temperatures.Through the modelling process, the influence ofthe first two groups of factors on the temperatureprofiles is determined, and secondary profiles arederived from which irregularities results fromthese influences have been removed. Where characteristicresponses indicating water flm are present,the data are usually not suitable for theclimatic analysis. In suitable data sets the finalstep then takes available information on thedates and direction of climatic change at the BUTfaceand generates the amplitude of such changesbackwards in time. Since the mathematical solutionsare non-unique it is necessary to use independentlyderived information on dates and amplitudesand to use geothermal profiles to determinethe unknown parawter.Other applications of the technique are todetermine the development or degradational historyof permafrost, whether it is contemporary or relicin nature. and to determine approximste ice-basetemperatures beneath the Wisconsin ice sheets,provided the drill holes are sufficiently deep.Such modelling of geothermal data carried out attwo sites in northern Quebec indicates major differencesin the permafrost and glacial historybetween the central highlands of Ungava and a lowlandregion approximately 500 km southeast.

325EXCAVATION RESISTANCE OF FROZEN SOILS UNDERVIBRATING CUTTINGSShingi TakasugiTechnical Research Center, Komatsu Ltd.Kanagawa, JapanA. PhukanUniversity of Alaska, 3221 Providence AvenueAnchorage, Alaska 99504, USAThis paper presents dynamic laboratory experimentalstudies of frozen sands and silts at temperaturesvarying from -2Oc to -11"C, using variouscutting velocities from 2 mm per second to 18mm per second. The 6-Hz vibration model used wasvaried from 1.3 mm amplitude to 4 mm amplitude.Theoretical analyses of the cutting resistance offrozen soils under vibration cutting are formulatedto explain the failure characteristics obtainedduring the experimental work. Energy ratio versusthe number of contacts per inch of cutting (Nc)plots show a similar tendency for both silty andsandy frozen soil samples; that is, as the energyratio increases, Nc increases. 'he contact lengthbetween the soils and the tool in the vibrationcycle is inversely proportional to Nc. At highNc, the contact length is too small to cause soilfailure and thereby increases the vibration energy.Relationships between the energy ratio and Ncat various amplitudes, €or both soil types, show agreater energy requirement at 4 m amplitude ofvibration than at 1.3 mm amplitude, in spite ofthe identical draft energy reduction at both vibrationamplitudes. It is possible that by inducingvibration of the cutting tool, a reduction indraft energy can be obtained and thereby the excavationprocess can be efficiently executed in frozenground.SHORELINE REGRESSION: ITS EFFECT ON PERMAPROST ANDTHE GEOTHERMAJ, REGIME ,CANADIAN ARCTIC ARCHIPELAGOA.E. Taylor and A.S. JudgeEarth Physics BranchDepartment of Energy, Mines and ResourcesOttawa, Ontario, Canada KIA 043D. DesrochetsDepartment of Geography, University of OttawaOttawa, Ontario, Canada K1A 6N5In the Queen Elizabeth Islands of the CanadianArctic Archipelago, the late Quaternary eventwith the most profound influence on ground temperaturesis shoreline regression accompanying postglacialisostatic uplift. The coastal margins ofmany islands have experienced hundreds to severalthousand years of submergence since 8,000 yearsago. The effect on the geothermal regime is farfrom subtle because of the large contrast betweenarctic air temperatures and sea temperatures,Permafrost thicknesses measured today reflect thissurface temperature history. Two deep wells 1 kmapart on Cameron Island have measured permfrostthicknesses of 726 and 660 m; the geothermal analysisattributes the difference entirely to thefirst, and higher, site having emerged from thesea around 7,000 year B. P., about 2,000 years beforethe second. Inland sites on the Sabine Peninsulaof Melville Island may have, in a similarlithology, permafrost twice as thick as coastalsites. The geothermal analysis explains this variationin term of a simple sea regression modelderived from emergence curves published for theregion.A COMPARISON OF SUCCESSIONAL SEQUENCES FOLLOWINGFIRE ON PERMAFROST-DOMINATEDAND PERMAFROST-FREE SITES IN INTERIOR ALASKAK. Van CleveForest Soils Laboratory , University of Alaska,Fairbanks, Alaska 99701, USAL.A.ViereckInstitute of Northern ForestryFairbanks, Alaska 99701, USAThe structure and function of upland interiorAlaskan forest ecosystem has been examined acrosstwo secondary successional sequences. One, themost common in interior Alaska, follows fire inblack spruce stands on permafrost sites. The other,less common sequence follows fire on warmer,generally south aspect sites and passes through ashrub and hardwood stage to white spruce. Onblack spruce sites, the thickness of the forestfloor is a key factor responsible for maintainingmoist soil, low soil temperatures and permafrost.Soil degree-days range from 1250 to 1000 degreedays1 to 5 years follwing fire. In mature blackspruce temperature ranges from 500 to 800 degreedays.The active layer thickness in later stagesof this succession is usually from 40 to 60 cm.Following fire it increases for several years andmay reach 1 m. In the south aspect white sprucesequence, soil temperature approaches 1400 degreedaysin heavily burned forest in contrast with 9m0to 1000 degree-days in mature white spruce. Onthe black spruce successional sequences, low soiltemperature results in the lowest rates of soilbiological activity, nutrient cycling, and, inturn, the lowest tree productivity. Net annualabove-ground tree production ranges from about 7metric tons per hectare on the warmer, south aspecthardwood-white spruce sequence to less than 1metric ton per hectare on the black spruce sequence.SOME CONSIDERATIONS REGARDING THE DESIGN OFTWO-PHASE LIQUID/VAPORCONVECTION TYPE PASSIVE REFRIGERATION SYSTEMSE. Yamk. Jr. and E.L. Long

326Arctic Foundations, Inc., 5621 Arctic BoulevardAnchorage, Alaska 99502, USATwo-phaee liquid/vapor convection type passiverefrigeration units are widely used for permafrostfoundations and earth stabilization. ABpectsthat are of primary importance to the designerinclude determination of an effectivefreezing radius for a unit, calculation of a thermalresistance for the soil surrounding the embeddedportion of the unit, and estimation of an appropriatethermal resistance for the condenserportion of the unit. Design charts and formulasare presented to estimate these values and demonstratethe sensitivity of varying key paramterssuch as soil type, wind velocity, condenser surfacefinish and spacing. Computations for twodifferent design applications are detailed.THE STABILIZATION OF THE NANISIVIK CONCENTRATORFOUNDATION, NANISIVIK MINES LTD.D. WilliamsStrathcona Mineral Services Limited401-44 Victoria Street, TorontoOntario, Canada M5C 142Nanisivik Mines Ltd. operates a 2,000-ton/dayunderground zincllead mine in the Canadian Arcticon the north end of Baffin Island at 73'N in anarea of thick permafrost. The concentrator buildinghouses the powerplant, workshops, warehouseand offices. The grinding dlls and generatorsproduce heavy foundation loads. A suitable constructionsite was selected following drilling andsurface inspection. All bore holes within thesite area showed a gently dipping dolomite as bed-rock. The ice content was negligible, being presentonly in small vugs or as thin coatings alongbedding planes.The steel frame building was erected during1975 and in the following year minor cracks werenoticed in the concrete block partition walls. Asurvey of the steel column bases was carried outto provide reference elevations for future observations.Accelerated movement was observed during1979, with elevation changes on the order of 50 mmbeing recorded over the course of the year.In order to determine the nature and extentof this problem a number of holes were drilledwith a diamond drill through the floor of thebuilding. These holes indicated an ice lens underthe building at an average depth of 10 m whichvaried in thickness from 1 to 1.5 m. In someareas the ice had completely melted, leaving awater-filled void. The overlying crown pillar ofrock on which the building had been constructedwas subsiding into this cavity.Several support methods were tried which involvedplacing tailings, cemented tailings andgrout into the existing void and into voids whichwere deliberately created, in an attempt to arrestmovement. When none of these methods guaranteed apositive solution to the problem the decision wasmade to tunnel in under the building and to providepositive support in the form of concrete pillars.Stress meters have been placed in selectedpillars. The crown pillar has been monitored byregular level surveys on the building column basesand by the installation of wire extensometers andthermistors into the rock.This paper deals with the investigations carriedout, the remedial attempts, the installationof ground movement monitoring instruments, temperaturemeasurements, the mining problems in ice,the pouring and setting of concrete in freezingconditions, a study of the heat transfers Involved,and a review of the successful solution ofa unique problem.

~ ~~~~Gerald E. NelsonDepartment of Geology, Casper bllege/University of wyanins at CasperCasper, Wyoming 82601, USAAt least four levels of gently sloping erosional surfaces, representing at leastfour periods of erosion, axe present in the Bighorn Canyon area of southcentralIW~tana. The truncated bedrock surfaces are irregular in detail, and are overlainwith a thin (1 to 3 m) veneer of diamictm. The diamicton is very poorly sorted,and contains erratic blocks up to several metres in dimter. Most of the finegrained portion of the diamicton originated f m formations beneath the veneer.Forrnerly much mre active frost wedging and frost churning are indicated by thewide size range and angularity of the erratic blocks, fragmxkation and disaggregationof subjacent forrmtions, and the thorough mixing of these mterials. Frostwedging of bedrock is thought to have been the main process of @itrent erosion; noevidence or prior planatian was found. The meent of the diamicton is interpretedto have been rnainly by solifluction, as indicated by the extensive, sheet-likegecmetry of the depsits, preferred dmnslope block orientations, the presence ofdiamicton lobes, pd the trransportation of huge blocks several kilmters on slopesbetween and 11 . he major conclusion drawn from data and interpretationspresented in this paper is that these pedbnts are cryopediments, dwelopedthrough the action of intensive frost processes in a periglacial envimnnent.lxlFmmmNumerous studies have dccumnted the expansionof the periglacial zone that occurred during thePleistocene. Various features are interpretd tohave formed under periglacial conditions, but, withthe excepkion of inactive sand wedges and ice-wedgecasts (Black, 1969), the recognitim of manyfeatures is difficult and may be subject tomltiple interpretations (French, 1976, Chapter12). Ice-wedge casts and inactive sand wedges havebeen recognized and studied in the high basins andplains of Kyaung (Mears, 1981, and Nelson, 1980)and Montana (Schafer, 1949). It muld seem highlylikely that additional relict periglacial featuresmld be found in this region, but, to date, littlework has been done on the problem.Deposits of blocky, poorly sorted diamicton,veneering pdhts, are present in m y of thehigh valleys and basins of Wy&g and Montana(e.g. Bailey et al., 1968, and Nelson, 1983, p.129). The pedkents and their associated veneersappear to be similar to cryopedinmts (Chk andDemsk, 1970). One such case, in the Bighorn CanyonNational Recreation Area in southcentral Montana,was studied in detail (Nelson, 1983). The presentpaper s mizes the results of that study.DESCRIPTIONS OF 'B33 FW3l"STHEIR DLAMICXON VENEERSGeneral CharacteristicsANDAt least four levels of gently inclined pedktsystems, each consisting of several individualsurfaces at or near the m elevation above localbase levels, are present in the transition zonebetween the Pryor Mountain front and the BighornRiver (Figure 1). The erosional surfaces truncategently-dipping IWSOZO~C sandstones, siltstones,and shales. They are covered with a thin (1 to 3m) veneer of poorly sorted, blccky diamicton.Downslope profiles of the surface are snmth,hyperbolic curves, steeper in their upper portionsand of such shallaw concavity in their lmrreaches that they are nearly rectilinear. Inpl? view, the pdiments are very nearlyrectilinear. Average size, slope, and elevationof each pedhnt system are presented in Table 1.TABLE 1. Sumnary of Size, Slope, and Elevationof Pedht systems.Ave.Area Ave.Lmqkh Ave.Width Ave.Slope Ave.ElwQp 1 1.03 1.2616 -1es1.35 5-11 1330-1490"""""""""""""""""~""""""-ap 2 -25 -76 .39 4-8 1380-150024 mamplesGp 3 1.14 1.04 .55 2-3 1425-152018 &E5rampleSQp 4 .20 .76 .55 3-6 1500-15809 Exaqles327

328WESTEASTQP 4Figure 1. Generalized geological cross-section between the Pryor Mountains on the west and the BighornRiver on the East, shming the area of pedimnt developrent. The pediments shown on this cross-sectionare diagramtic, to shm the relationships between the various pedimmt systems.Most @me.nts join steep upper slopes withrelatively sharp angles of inflectian. This anglecoincides with changes in bedrock geology onlyalong the mtain front fault. others do not joinsteep upper slopes at all; instead vley ocm ontop of isolated, butte-like landforms. The lcwerends of the lmst surfaces grade to presentaystreams or, in a few instances, to ledges ofresistant rock. The lmer edges of pediments inthe higher system project as planes into spaceover the surroUnaing lowlands. The diamictonveneers of all @inrents contain erratic blocksthat could only have originated at outcrops alongthe front of the Pryor Mountains. This indicatesthat the isolated pediment remnants were, at onetime, connected to a source of erratic material,either at the mtain front or a higher pedht.Isolated surfaces are often surrounded or nearlysurrounded by pedimsnts of 1-r system. Suchcrosscutting relatianships allow classification ofthe systems into a relative age sequence, with thehighest king the oldest, and on down to the lmstwhich is the youngest.?tu0 examples of pedirrents were selected fordetailed study of the diamicton veneer and thetruncated bedrock surfaces, one each frm the lcwertwo systems. Gully erosion and construction of ahighway through the study area provided goodcross-sections of these pediments and theirveneers.Pedht VeneerNatural and man-made eqmswes indicate agenerally uniform thickness for the veneer, fran 1to 3 mtres, with about 2 metres being the mstcmrmn (Figure 2). The veneer consists of one,rarely two or three, layers of poorly sortedraterial. Individual layers consist of chaoticmixture of various grain sizes, with a tendency forlarger than average blocks to occur at or near thetop of the layer (inverse grading).

329Blocks in the diamicton reflecthe compositionof fomtions expsed in source areas directlyupslope f m the pe3jlllents. They have lowsphericity and range betwen bladed and elongate inshape. Estimates of roundness, using a ccmpariscnchart, range frcm very angular to subrounded. ~twas impractical or jmpossible to mame a largeenough nmbr of blocks to obtain an average blocksize. An estimate of maximum blcck size was madeat sample sites on the tw pediments selected forstudy (sample sites are same the as those shm inFigures 4 and 5). These esthtes consist of theaverage ncminal diatneter (the diameter of a spherewith the sam volw as the block) of the 10largest blocks found within a 100 metre radius ofeach sanple site. Average naninal diarrreters of thelargest blocks range between 40 and 250 an forp d h t 1, and 40 to 350 for pediment two.Based on sand-silt-clay ratios of samples takenat the same sample sites, the matrix of thediamicton is a silty sand; mst of the sand is inthe very fine to fine-sand size range. Histogramsof average grain-size distributions of the s msamples shcw that the matrix is texturally andccmpositimlly b-1 (Figure 3). Thecoarse-grained ride is ccmposed chiefly of erraticmaterial fmm Pryor mtain source areas, mainlymbnate rccks and chert: this type of materialdecreases in abundance with decreasing fractionsize until, in the fine-grained ude, mst of thematerial is -sed of disaggregated grains of thesubjacent formation (PermD-Triassic Chugwatersandstone and siltstone).Block FabricBecause of the obvious indication of blocktransportation, the orientation the of long axis of100 blocks was determined at each sample site onboth pdhts. Fabric diagram (Fiqwes 4 and 5)are generally -sed of two well-defined modes;me oriented downslape and a second, generallym r , parallel with the contours. The strengthof the damslope m e increases with increaseddistance f m source areas. In the 1-r reachesof the m b t s , the cross-slope rrcde is as strongor stronger than the damslope rcde.Diamicton I&esPEDIMENTThe apparent srmthness of the land surface whenviewed fran a distance is, upn close inspection,broken by lobate acmlations of blocky diamicton(Figure 6) , The lobes are elongate damslope, havearcuate, oonvex fronts, and merge into the generalslope or are covered over by additional l&es inthe upslope direction. Very large blocks are oftenfcund at lobe fronts, packed tightly together. Thelmst two Himent syetms have the clearest andgreatest nmber of lobes, while the upper two haveat best only vague, arcuate concentrations ofdeqly inplant& blocks.-3-2 -I 0 I 2 3 4Veneer Bedrock InterfaceThe eroded bedrock surface is the actualpedht; the zone containing the uppemst portion Figure 3. Average grain-size distributions ofof the bedrock, the @im?.rlt, and thf? luwemst diamicton mtrix. Diagonalshadingrepresentsportion of the diamicton is herein named the erratic material, mainly carbrmate rock fra-ts,veneer-bedrock interface. In all expsures, the and the clear area represents material derivedinterface is a relatively thin zone, ranginq fran a fran subjacent formations.few centirnetres to a few tens of centhtres thickIO50PEDIMENT 2I

330(figure 7). Many interfingerings betweenbroken and disturbed bedrock and over- thelying diamicton are present. Below theinterface, primary bedding is preservedand the bedrock is in place although cementationis lacking and they are unconsolidated.Between these fragments, thematerial is a fine-grained mixture of disaggregatedgrains from subjacent formationsplus erratic carbonate clasts. Thefragmented bedrock zone grades upwardsover a very short distance into typicaldiamicton, containing fewer local clastsand more erratic clasts.M-RWORTHPERCENT OFC.1. 40'ffi20PERCENT OFOB8ERVATIOW810 EACH 10 DEOREE8ECTORn4120'VKILOMETER C.I. 80'Figure 5. Fabric diagrams of the long axes of 100blocks at each sample site, pediment two.and stone cairns used by prehistoric people, anddevel-t of soil horizons within the diamidan.Origin and mvemmt of DiamictonAnalyses of the samples prove that the dMctonis tjexturally and catpsitionally b-1.The only possible sources for the generallymarse-grained Mnponents are outcrops alonq thefront of the Pryor Mountains. The win murce forthe bulk of the fine-grahd ocmponents is bedrocksubjacent to the diamictm deposits. The angularityand wide size range of all these canponentsIntroductionsuggest that they were produced by frost wedging(see, for example, Washbum, 1980, p. 76-78 and p-UnpLicit in the following discussion is the 222-223). Gradual, continual mixhg of materialassumption that the diamictm deposits are not ncw f m the tvm source areas is indicated by theforming or mxlinq and that pediment erosion is no diffusecontact between the veneer and thelonger takinq place. Evidence for lack of underlying bedrock. Mixing could have occllrreddiamicton m3vanent consists of fence lines and during diamicton mmemnt or by frost churning ormadcuts that remain undisturbed, blocks whose both.exposed surfaces are covered with lichens and whose The type of slope -ts reported in theburied surfaces are covered with caliche, pine literature which produce deposits withtrees sweral inches in dimter growing in the characteristics similar to those described in thisdiamicton, undisturbed stone circles or tipi rings

3310*IMETERPOlITlON AND ORIENTATION OF BLOCK0 OREATER THAN OR LCIUALTO PI DM 8HOWN lY: /Figure 7. Camera lucida drawing of thebedrcck-veneer interface, p3-t two. Thestimled pattern is bedrock (PedriassicChugwater formation in this case) which isin-place at the bttm of the drawing and asseparate frarpllents elswhere. The vertical stripepattern represents erratic carbonate clasts, thehorizontal stripes represent diamicton rich isdisaggregated grains frm the subjacent formation,and the clear area represents typical diamictonwith fewer local clasts and mre erratic clasts.Disaggregated grains of the local bedrock aremixed thoroughly into the dian&ztm even near thetop of the deposit.Figure 6. Bruntrm and tape sketch map of a 50 by50 mtre site on pediment one. The lobesillustrated here are typical of those found on theher txm pediment systems.paper axe solifluction and frost creep (forexample, see sumoary in Washburn, 1973, p. 189).Solifluction is indicated by: 1) obvious m m tof a silty diamicton, containing huge erraticblocks, on very gentle slopes; 2) lobes ofdiamicton; 3) preferred downslope orientations oflong axes of blocks; and 4) the uniformly thin,sheet-like gemetry of the deposits. In additionto the abwe, intensive frost creep is indicated bythe concentrations of blocks found at lobe wins(Benedict, 1970).It is possible that the flcw ccmponent ofdi&cton IOEWVXI~ was gelifluction (mxtement overa frozen substrate) rather than solifluction(substrate not necessarily frozen). Tpleaccurmlated evidence of fomrly mre intensivefrost actim suggests that at least a seasonalfrost table existed in the area tkroughout mre ofthe year than is presently the case, but positivepmf of permafrost is 1acku-q. Slopewash andstream adion must also be considered as probableadjunct processes of erosion and transportation,but direct evidence of these processes is lacking.Erosion of Pedimentsmlopuent of lower, younger surfaces in thestudy area was at the expense of higher, oldersurfaces, as indicated by the isolated, buttelikepediment remnants surrounded or nearly surroundedby Lower pediments. The fact that higher surfaceshave retained their pedimnt form suggests thatbackwaring of steep slopes at the upper edges ofthe pedhts is daninant over damwearing.However, sane reg-rading must take place as thepediment extends itself upslope and gently slopingporticns replace steeper portions.%lifLuction (or gelifluctim) rrrsvanent byitself appears to have little erosive ability.This is demonstrated by vertical velocity profilesshming nmranent concentrated in the upper fewdechkres, and attenuating to zero at scme shal-1m depth (Rudberg, 1964, and Wiliams, 1966) , andby numerous cases of solifluctian lobes overridingorganic material (e.g. Benedict, 1970). The angularityand wide size range of fragmmts of theeroded kdrcck in the diamicton suggests -thatfrost wedging was responsible for pediment emsim,with the material thus produd mved

332damslope mainly by solifluction. No indicationswere found during the COuTse of this study whichwwld suggest that the bedrock surface had beeneroded by, for example, stream action, prior todiamicton memmt. Mermore, the diffuseveneer-kdmck interhce indicates that diamictmmvmt and kdrcck planation were contemporaneous.The luwest @hats in the Bighorn Canyon areaare between the foot-portions of higher slopes andlocal base levels. No similar features have developedon the front or the crest of the M r-bin Range. In this geamrphic position, andwith evidence suggesting their formation byperighcial processes, the pediments in the studyarea may more properly be tend cryopedirrents(Czudek and Demek, 1970).Age of Biqhorn Canyon Pedim=ntsRelative age relationships amng the four levelsof pedhts have been established on the basis ofcrosscutting relationships, relative agesequence is supported by differences in microrellefof blocks and labes; upper pedim?nt systems areSMOther and differ in surface W e fran eachother and fran the lmx two systems. The highestpdiment system is the oldest, and each successively1-system is -. No evidence for theabsolute ages of the m t s is available. Theyare, in general, Pleistocene in age because: 1)similar features are not ncw dwelopinq in thearea; 2) the youngest system grades to levelsdated archaeolcgically at least as old as 8,000years (I-Iusted, 1969): and 3) the accumulatedevidence presented in this pap strongly indicatesa relationship between @hat erosion anddiamicton mvemmt, and Cold climatic cormditims.Clirrvatic ConsiderationsInactive sand wdges and ice- casts havebeen found in numrous scattered localitiesthroughout the state of wyanins by &kxcs (1981) andNelson (1980). Fossil priglacia1 features havebeen found at leasth v as 1,500 msl in thenorthern Bighorn Basin, 35 kilanetres south of thepresent study area. Although similar features havenot yet been found in the Bighorn Canyon area, itseans likely that this area (1,300 to 1,600 masl)also exprienced a permfrost climate duringPleistacene cold periods. Late Pleistocene vertebrate mterial fran Natural Trap Case , threekilcmetres smtheast of the premt study area,include remains of tundra dwellers such as thecollard lemning Dicrostmyx sp. (Gilbert et al.,1978). Although a spatial relationship betteenpermfrost features and tundra dwllers, and&bents in the BighornCanyondces&pmveaterrporal relationship, it does support the interpretationsbased on gecm3rphology alone. At thevery least, the area had a clhte rigomus enoughto have supported mre intense frost wdging, frostchurning, and solifluction than is presently thecaw. The cryopediments in this area indicate thatthe effects of Pleistocene periglacial climates inthe Middle Rocky Mountains are mre widesprd thanpreviously daronstrated.AC!UlOWl@dg€WIltSPartial funding for this project was providedby grants fran Si- Xi and a DissertationFellwhip f m the University of Kansas. I amvery grateful for this and aid, the support of thefaculty in the aepartment of geology at theUniversity of Kansas.REFmm3s CITE0Bailey, R.L., Harp, E.L., Jasmin, P.H., &en,LA, Lavin, S.J., Wkin, R.L., Meuller, R.G.,Schneider, G.B., Stradley, A.C., Tadd, S.G., andbbntagne, J. , 1968, Pedhts of the northeastslope of Canyon Mountain, Livings-, Park Co.,Montana: Montana State Univ., Earth ScienceMiscellaneous &search Series, no. 1, 17 p.Benedict, J.B., 1970, Downslope soil mvmmt in aColorado alpine region: Rates, prccesses, andclirmtic significance: Arctic and AlpineResearch, V. 2, p. 165-226.Black, R.F., 1969, Climatically significant fossilperiglacial phenanena in northcentral UnitedStates: Biuletyn Peryglacjalny, v. 20, p 225-38.Czudek, T., and J., 1970, Pleistocene CryOpdkmtationin Czechoslovakia: Acta Waphicamziensia, v. 24, p. 101-108.French, H.M., 1976, The Periglacial Envirormwt,Lmgrmn Group Ltd., Irxldon, 309 p.Gilbert, B.M., Martin, L.D., and chanko, S A ,1978, Paleontology and paleoecology of NaturalTrap Cave, waning: 20,000-10,000 BP: Z4'ericanQmkernary Association, Abstracts 5th BiennialMeeting, Iuberta, Canada, p. 203.Husted, W.M., 1969, Bighorn Canyon archaeology:smithmian Institute River Basin flweys, Publicationsin Salvage Archaeolcgy, no. 12, 138 p.&am, B., Jr., 1981, Periglacial wedges and thelate Pleistocene emrironmmt of yrcming's interrrrmtanebasins: &ternary Research, V. 15, p.171-198.Nelson, G.E., 1980, Inactive sand wedges at Casperwaning: Indicators of the former presence ofpermfrost: Geolwical Society of America,Abstracts with prcgrams, v. 12, no. 6, p: 299.1983, Origin and paleoemrimrmental significanceof pdirrrents in the Bighorn Carryon area, mumcentralmtana: unpublished PbD muscript, TheUniversity of Kansas, Lawrence, Kansas, 159 p.Schafer, J.P., 1949, Sane periglacial features incentrallbntana: Jaurnal of kl., 67, p154-74.Rudberg, S., 1964, Slow mass mwmnt processesand slop devdopnent in the Mrra Storfjallarea, mthern Swedish Lappland: Zeitschriftfur~rpholcgie N.F., supplarrent 5, p. 192-203.Washburn, A.L. 1973, Periglacial processes andenvirorrments: st. Martins Press, New York, 320 p1980, Geccryolq: a survey of periglacial processesand envimrmnts: John Wiley and m,New York, 406 p.Williams, P.J. , 1966, kmslape soil mverent at agubarctic location with regard to variationswith depth: Canadian Gwkdmical Journal, v. 3,p. 191-203.

ELECTRICAL TIJAIJING OF FROZETI SOILSAlfreds R. JumikisIn foundation engineering activities in the Arctic, permafrost is a dominant factorthe builder nust cope with. To facilitate excavation and foundation work in frozensoil, the latter can be loosened up, among other methods, by thawing electrically.Electrical thawing is a convenient and expedient method for application to small,dispersed structures, especially in built-up areas during cold seasons of the year.This article presents a method of calculation for electric thawing of frozen soils.The thawing system is a hexagonal electrode grid. It consists of six, verticallyembedded, electrodes around one central grounded electrode, Single-phase, three-wirealternating current for thawing 17as used in this calculation.INTRODUCTIOllThe principle of radial, electrical, thawingof a frozen soil by means of vertical electrodesmay be described as follows. A soil, through whichpasses an electric current, heats up due to resistivedissipation, that is, the applied electricalenergy is transformed into an equivalenr thermalenergy.The electrode-soil-electrothermal system underdiscussion is a vertical cylindrical system wherean a-c current emanating from the vertical, cenrralelectrode flows radially into the soil. There arealso currents flowing between adjacent electrodeson the periphery of the hexagonal &rid.The region of influence of thawing of a uniformsoil around one electrode is assumed to be avertical annulus of soil whose inner radius is re(the outer radius of the electrode), and ourerradius is r, see Figure 1. Because of the electricalresistance of the entire body of the frozensoil, Joules' heat is generated Iten masse" withinthe soil around rhe electrode.ElectrodesFor direct, radial, electrical, thawing offrozen soils, solid, steel electrodes, -25.4 mm to-50.8 mm in diameter, may be used. Because lateraland downward drainage of the melt water of ice isblocked by the still frozen permafrost around theelectrodes, the thaved soil becomes more or lesswater saturated. To cope with a muddy site condition,the melt water can be removed and dischargedif perforated metal pipe electrodes, instead ofsolid steel rod elecrrodes, are used,The electrodes may be installed in the frozensoil in various electrode grid patterns at equalspacing of approximately s = 2-3 m, center tocenter, in a straight row. The spacing of rows is-2.5 m to -4.0 m. The array of electrodes in anelectrical thawing system may also be in staggeredrows (equilateral triangular pattern or in acheckerboard arrangement). Figure 1 shows a hexagonallyarranged electrode grid pattern.For safe operation of an electrical thawingfacility, the electrical thawing installation mustbe grounded. The site must be fenced in, and providedwith warning signs. Also, for reasons ofsafety, direct electrical defrosting (with bareelectrodes) of frozen soils containing metallicores should be categorically prohibited becausestray electric currents in the ground.ectrodeFIGURE 1 Hexagonally arranged electrode gridpattern. Irorizontal cross-section through electrodesand frozen soil.El. = electrode.G = grounded tap electrodere = de/2 = radius of electrode.r = outer radius of frozen soilcylinder.s = 2r = spacing of electrodes.P = pocket.of333

334THAWINGGenerally, the process of thatling of frozensoils may be visualized to take place in threemajor steps:1. heating of the frozen soil from its initialtemperature Tin to the temperature of themelting point Tm of the soil ice;2. isothermal melting of soil ice at constantmelting temperature Tm.The latent heat of melting is suppliedby heating the soil electrically and theice in the frozen soil changes its phasefrom solid to liquid. A pure ice transformsto water at a theoretically constantmelting temperature of Tm = O'C. At highmineralization of ice, its melting beginsat less than 0°C. The change in the phaseIce to water Is accompanied by a simultaneousdecrease in the resistivity of thesoil, and by changes in its thermal conductivityand heat capacity. And,3. after melting of the ice, the thawed soilcontinues to be warmed up to some final,positive, design temperature Tfin.The accumulated heat in the thawed soil disrributesslowly beyond the designed that7 boundaries, andpractically increases the design-volume of thethawed soil. This heat might help to thaw the"triangular" spaces or "pockets" between themerged, already thawed soil cylinders.FIGURE 2 Hexagonally arranged vertical heaters.1-brizontal cross-section through heaters and thawedand frozen zones of soil.B = heater.'h = dhl2 = outer radius of heater.5 = radius of thatred zone.r = outer radius of frozen zone.s = 2r = spacing of heaters.m.b. = moving isothermal thaw-frostboundary.P = pocket.In Figure 2, the cylindrical surface whoseradius is 6, is the interface between the thawedand frozen zones of the soil. Bere the absorptionof the latent heat of melting of the ice occurs.This isothermal interface is also known as the movingisothermal boundary between the thawed andfrozen zones of the soil, On this isothermalboundary, changes in phase and thermal propertiesbring about a discontinuity in soil temperaturedistribution, and in heat transfer. Because of thediscontinuity, as well as because of the nonlinearitythat results upon introducing the latent heatequation into the system of Fourier's heat transferequations for frozen and unfrozen states, there isno general, exact, closed-form solution for changesin phase in cylindrical coordinates available.Further discussion on thawing of this type is beyondthe scope of this article.As mentioned already, on passing of electricalcurrent through the cylindrical body of the frozensoil around the electrode the soil heats upen masse because of the electrical resistance ofthe soil. The frozen soil changes temperature, andeventually the ice of the soil melts: .Recausethere are no thermal gradients in this thawing soilsystem, there is no heat flow. Consequently, thereis no isothermal phase change boundary present uponchange of ice to water.The interwoven complex phenomena of electriciryand electromagnetism in frozen and thawing soils,the complex nature of the multicomponent electrothermalsystem of soils, and the multitude of soilphysical and electrical properties indicate thatthermal and electrical calculations during electricalthawing of frozen soils are very difficult.Therefore, to make such a problem accessible toreasonable calculations, the thawing problem mustbe idealized by making simplifications and assumptions.Simplifications facilitate a practicalapproach to dealing with the electrical thawingproblem in frozen soils. The solution to such asimplified problem can be acceptable in practice,but, the solution to the problem of artificialthawing of frozen soils electrically in a cylfndricalsystem can be treated only approximately.Assumptions made for electrical thawing of frozensoils are:1, the soil is homogeneous, uniformly frozen,permafrost;2. the cryogenic texture of the frozen soil ishorizontally layered soil platelets (scales)(Jumikis, 1973l; 19782> ;3. the frozen soil is fully saturated witht.7a t er ;4. there are no heat convection processes;5. to avoid undue upward flow of heat from thethawed soil to the atmosphere, and to protectthe already thawed soil from refreezingduring a cold season, the ground surfaceat the site is covered with an appropriatethermal insulation (as is commonlypracticed in other methods of thawing offrozen soils) ;6. the upward flow of the terrestrial hear fromthe interior of the earth toward the undersideof the permafrost, being relativelysmall, is ignored;7. the heat loss from the thawed soil to thefrozen subsoil (or to the unfrozen subsoil,

335if applicable), as is usually done, may beincluded as a percentage of the overallenergy loss of the thawing system;8. the initial temperature Tin of the uniformlyfrozen soil is constant.ELECTRICAL RELATIONSThere are various electrode grid configurationspossible. Figures I, 3 and 4 show a plan of ahexagonal grid or group of six vertically embeddedelectrodes. They are arranged radially about onecentral, grounded electrode in a triangular pattern.Each electrode interacts with adjacent electrodesspaced from one another at 6 = 2r (Figures 2 and3). It is assumed that in such an electrode gridall electrical paths between the electrodes haveequal electrical resistance R because of the hexagonalgeometry of the grid (Figure 3), and becauseof the assumed homogeneity of the soil, However,the homogeneity may vary more or less with thelocal conditions at the site, especially as thethawing of the soil progresses. Notice inFigure 3that in each of the six inner or radial resistancepaths the voltage is U, and that the power in thesix outer or circumferential paths will be fourtimes the power in the six inner or radial paths.The grounded center tap is connected by an insulatedzero wire (the third wire) to the singlephase alternating current three-wire electricalpower line.The progress of thawing may be monitored bytemperature measurements of the soilin 'cemperaturemeasuringboreholes. Also, soil cores can be extractedto check whether all ice inclusions in thesoil are melted.Soil ResistanceThe electrical resistance R between a pair ofparallel cylindrical electrodes in an infinite,homogeneous medium, assuming the spacing s of theelectrodes is large compared to their diameter, isgiven by Della Torre and Longo (1969) asP, = (p/2*n*FI )*Rn(s/re),elwhereR - soil resistance, ohmp = resistivity of soil, in ohm metersI! = embedded length of an electrode, inmeterss = spacing of electrodes, in metersre = radius of electrode, in metersThe electrical resistivity of soils depends onmineralogical composition, porosity, moisture content,amount of electrolytes in the soi1,cryogenictexture, ice content, temperature, and possiblysome other factors.According to Rennie, Reid, and Henderson (19781,the range of resistivities of an unfrozen lowplasticclay is 25-45 C t n , that of a frozen lowplasticclay is 40-80 h, that of a high-plasticsilt in an unfrozen condition is 40-60 h, andthatof a frozen high-plastic silt is 60-110 Gm.PowerThe power loss in an electrical resistance traversedby an alternating current is expressed bythe well-known formula2P = u /R,(2)where P = the power lost in heating thewattsU = voltage, volts(1)material,Thus the power P, in each of the six radial electricalresistance paths is:2Pr = U /R, (3)Connectline IElectrode2JConnrctline 2I0420G Electrode@Zero wire( neulrol 12I2Connect line IFIGURE 3 Radial and peripheral electrical resistancepaths in soil (after personal communicationwith Prof. C. V. Longo),G = grounded central tap electrode.I = current.R = electrical resistance of soil betweeneach pair of electrodes.U = voltage.CT = central tap." l " lFIGURE 4 Connection of electrode grid to a singlephasesource of electric power.G = grounded central tap electrode.U = voltage.

336because the volrage is U for these paths. Thepower P in each of the six circumferential pathsis2PC = 4.U /R,(4)where k = a coefficient.Then the ice content istli = W-w 30% - 7.7% = 22.3%UWBy Eq. (l), the electrical resistances of thebecause the voltage is 2U for each circumferentialpath. The power PT in the entire grid of all elec- 'Oil under consideration are:for unfrozen condition: Bth = 23 ohmtrical paths isfor frozen condirion: RF- = 36.6 ohmLLPT = 6.P + 6*Pc = 30(U2/R)(5) The volumetric heat capacities of the frozen andthawed soil systems are given by the usualThe total power PT in the entire grid heats up thefrozen soil, as well as provides for the latentheat of melting for the soil ice upon its changing Cvfr = Yd ' (wi) + (cm) CwUw (8)state from solid to liquid.cvth = yd[Cmd + (cnnJ).(w)] (9)TtIERElAL CALCULATIONS The total energy is: requiredIn designing artificial defrosting facilitiesfor frozen soils, one needs to know the amount ofthermal energy Q (electrical energy E = Pnec*t),necessary, and the total duration of time t necessaryfor thawing the given volume V of the frozensoil.The thermal calculations of the necessary amountof heat Q to be added to the frozen soil for itsthawing are usually made for each of the soil com-ponents - solids, ice contents, unfrozen water -separately (Jumikis, 1977). The air component isusually disregarded in these calculations.where Q1 - energy needed to increase soil temperaturefrom Tin to Tm92 - latent heat of ice meltingQq - energy to increase soil temperatureThusfromExample3Given V = 110 m of a lour-plastic clay to bethawed electrically.The average initial temperature of this frozen soilis: Tin = -6'C.The average final temperature of the thawed soilis: Tfin = f2"C.The resistivities of this Soil are given as:pbnfrozen = 25 Gm and Rfr = 40 Ihn.3The unit weight of the soil is: y = 1950 kg/m .Its saturation moisture content by dry veight isThen Q1 = 447.3 kwh92 3423.4 h7h93 191.8 kwhQ, = (0 .I) (Ql+Q2+Q3) =(0.1)(4062.5) = 406.3 kwhQ = E = 4468.8 kwh.Assuming that the thawing project is planned tobe completed in t = 60 days, the required gridpower PT is:Moisture content at plastic limit of the soil:By Eq. (5), the necessary voltage U for thiswp L = 14%.necthawing work isThe piasticity index of this soil is: e7p.1. = 11%.Mass heat capacity of soil mineral partlcles orskeleton: Cmd = 0.20 kcal/l:g.'C.Mass heat capacity of ice: cmi=0.50 bcal/kg.'C.'net = [(Rfr/30)*PT]o.5 = 61.5 = 65 vMass heat capacity of water: cw=l.OO kcal/kg*'C.line-to-grounded center tap, or 2Unec 4 130 v line-Latent heat of melting: L = GO kcal/kg.to-line.Beat losses from ground surface of the thawing soilIf U is taken as 65 v then the power dissipatothe atmosphere: assessed at 9 10% of thetions in the frozen and thawed soils areenergy requirements.Pfr = 3.46 IW25.4 mm-diameter (= de) steel electrodes are spacedPth = 5.51 kw.s = 4.00 m apart.The thawing depth 11 should be 1.5 m.The effective depth of the embedded electrode isThawing TimeHel = 1.00 m. 1. The time tth in hours necessary for heating upThe mount of unfrozen water in frozen soil is the frozen soil from its initial negative temgivenby perature Tin < 0°C to theTm O°C of the ice in the soil ismeltingw = k wOW P.L.= (0.55)(0.14) = 0.077 (=7.7%), (6)tth = Ql/Pfr = 129.3 h = 5.4 days.

3372. Duration of time t for isothermal melting ofmice at T = O'C:mtm = QZ/Pfr = 988.6 h = 41.2 days.3. Duration of time tfin for final heating up thesoil from Tm = 0°C till final temperatureTfin = t2"C of the soil:tfin = Q3/Pth = 34.8 h = 1.5 days.4. Total approximate thawinE time:ttotal = tth + tm -+ tfin = 48.1 day,The required grid power is:3.46 kw for frozen soil, and5.51 kw for thawed soil.The necessary voltage is:Unec = 65 voltsThe total thawing time is:ttotal = 1155 hours < 1440 hoursThe electric power and its voltage can do thethawing job in 1155 hours.CONCLUSIONSUnder permafrost conditions, direct, radial,electrical thawing can be pursued year-round and atany time if electrical energy - from stationaryelectric plants or mobile generators - is readilyavailable at the site. This method would speed updefrosting time considerably as compared to hydraulicthawing, because the electric defrosting isindependent of climate, and temperature of waterand steam used in the other methads of defrostingof soils. The radial method of electrical thawingis good not merely for year-round thawing of frozensoils but it is also convenient for protecting thealready defrosted soils against their refreezing.The main disadvantages of the direct, radialthawing of frozen soils electrically are:a) a more complex thawing operation than thatwhen air, water, solar energy, or steam isused as a hear source for thawing;b) the relatively high cost of operation of anelectric thawing installation; andc) the necessity to adhere to strict safetyregulations in operating an alternatingcurrent electrical thawing installation withbare electrodes.In the future, in the economical development ofcold regions, artificial, radial thawing of frozensoils electrically will probably be increasinglyused.The natural thawing process of frozen soils bymeans of radiation heat or solar radiation is nottoo dependable for continuous, uninterrupted thawingwork, especially in cold climates. The hydraulicmethods of thawing of frozen soils such as bymeans of river water, warm water, and/or steam,take a lot of time and involve great, unproductiveheat losses.Today, calculations of thawing frozen soilcylindrical systems electrically are atill performedbased on incomplete soil electro-thermaldata.Although electrical properties of permafrostsoils have been studied for their own purpose and/or interest by Arcone and Delaney (1981); Olhoeft(1978); Rennie, Reid and Ilenderson (1978), andothers, there still exists a great need for systematicallyintegrated knowledge about electrical andthermo-physical properties of freezing, frozen andthawing soils, and the functional relationships ofthe various factors involved, with particularreference to radial thawing of permafrost. Of particularneed in calculations are usable values ofresistances and resistivities for unfrozen andfrozen soils as functions of soil geotechnicalproperties, and electrode grid configurations.ACKNOWLEDGMENTSThe author expresses his cordial thanks toProfessor Emeritus C. V. Longo of Rutgers University,Department of Electrical Engineering, for hisassistance on electrical circuits and power calculations,and detailed review of the draft of thisarticle. The writer is grateful to Dr. V. J.Lunardini, M.E., of the U.S. Army Cold RegionsResearch and Engineering Laboratory at Hanover,New Hampshire, €or his valuable suggestions andfinal editing of the author's article. Also, theauthor expresses his sincere appreciation toDr. E. €1. Dill, Dean, College of Engineering, andDr. E. G. Nawy, Chairman, Department of Civil andEnvironmental, both of Rutgers, The State Universityof New Jersey, for sponsoring tangibly thepreparation of this article.REFERENCESArcone, S. h., and Delaney, A. J., 1981, VHF Electricalproperties near Point Barrow, Alaska:Hanover, N.H., U.S. Army Corps of Engineers,Cold Regions Researchand Engineering Laboratory,CRREL Report 01-13, 24 pages.Della Torre, E., and Longo, C. V., 1969, Theelectromagnetic field: Boston, Mass., Allyn andBacon, p. 192-198.Jumikis, A. R., 1977, Thermal geotechnics: NewBrunswicl:, N.J., Rutgers University Press,375 pages.Jumikis, A. R., 1978l, Cryogenic texture and strengthaspects of artificially frozen soils, Proceedingsof the First International Symposium onGround Freezing, Ruhr University, Eochum,Germany, v. 1, p. 75-85.Jumilds, A. R., 1978', Some aspects of artificialthawing of frozen soils, %Engineering Geology,Amsterdam, Holland, Elsevier Scientific PublishingCompany, v. 13, 1979, p. 287-297.Olhoeft, G. R., 1978, Electrical properties of permafrost,& Proceedings of the Third InternationalConference on Permafrost, Ottawa, NationalResearch Council of Canada, v. 1, p. 127-131.Rennie, J. A., Reid, D. E., and Henderson, J. D.,1978, Permafrost in the southern fringe of thediscontinuous permafrost zone, Fort Simpson,N.TJ.T., 2 Proceedings of the Third InternationalConference on Permafrost, Ottawa, NationalResearch Council of Canada, v. 1, p. 439-444,

Closing Plenary SessionFriday, July 22, 1983TROY L. PlfwE- - Good afternoon, ladles and gentlemen.Welcome to the final formal session of theFourth International Conference on Permafrost. Wehave been meeting here in Fairbanks for the past' five days to listen to excellent papers on all aspectsof permafrost. Now we are gathered for afew final Items of business, a few closing remarks,and presentations. I would like to thankall of you on behalf of the Organizing Candtteefor attending the conference. I am sure you allagree that w had five days of very fruitful discussionwith friends from many countries involvedin permafrost research, and I know we look forwardto continuing these contacts in the days ahead. Iwould first like to call on Dr. A. Lincoln Washburnto read the necrology.Closing session of the Fourth International Con- chad Hammond, interpreter; P.I. Melnikov, Deleferenceon Permafrost, University of Alaska, gate from the USSR.Standing: Troy L. P&d, Chair-Fairbanks, Alaska, July 22, 1983. Left to right: man of the U.S. Organizing Committee for the con-Kaare Flaate, Delegate from Norway; Li Yusheng, ference; Governor of Alaska, Bill Sheffleld; ShiDelegate from the People's Republic of China; Jay Yafeng, Delegate from the People's Republic ofBarton, President of the University of Alaska China; Hugh French, Delegate from Canada; JerryStatewide System; A. Lincoln Washburn, USA; Mi- Brown, Delegate from the U.S.339

340A.L. WASHBURN - Ladies and gentlemen, it is importantfor the Fourth International Conference onPermafrost to honor our colleagues who have diedsince the last Congress. They include:Ivan Baranov - USSRRobert F. Black* - USASietse Bylsma - The NetherlandsRoger J.E. Brown - CanadaDon Gill - CanadaRobert Eilpin - CanadaReuben Kachadoorian - USAVladimir Kudryavtsev - USSRDaisuke Kuroiwa" - JapanRalph R. Migliaccio - USA.Edward Patten - USAVal Poppe - CanadaGeorgi Porchaev - USSRE.F. "Eb" Rice USAJanuary Slupik - PolandSigurdur Thorarinsson - IcelandKenneth B. Woods - USAKenneth A. Linell* - USATo commemorate these colleagues, and any otherswhose passing remains to be reported, let USrise for a moment of silence in their honor,Thank you.TROY L. PIhf - Alaska is the only state in the Unionwith much permafrost. In fact, 85% of thisstate is directly or indirectly affected by permafrost,and it affects almost all of the taxpayers,one way or another, in the State of Alaska. Thisconference is directly related to this state, evenmore than others. It was our pleasure last night,and it is as well today, to be joined at this conferenceby Governor Bill Sheffield. I would liketo now present the Governor of Alaska, Bill Sheffield.BILL SHEFFIELD - Thank you very much, Dr. Pgwwi. Itis an honor and a pleasure to again welcome thisdistinguished group of scientists and researchersto Alaska. I had the opportunity to enjoy dinnerwith many of you last evening. From all over theworld you have traveled to this conference, andfor that I not only welcome you, I want to takethts opportunity to also thank you. I welcome youbecause we in Alaska are proud of our state in aworld too often prone to the ills of mankind suchas air and water pollution. For example, we inAlaska are proud that YR still have a relativelyclean environment. And even though Alaskans endurelong and cold winters, a high cost of living,and smmers that are far too short, a clean andspectacular environment makes the living here veryenjoyable. So welcome to our state.I also want to thank you for coming here, becausethe wrk that you do is very important to mystate and nation. Indeed, it is important to theentire wrld because you know better than I thatso many of the resources we need for the survivalof the hman race are in the Arctic and Subarctic.The arctic regions of our state now producemoBt of the revenue that w enjoy as the 49thstate of the Union. If you haven't already, many*Died since the conference.of you will have the chance to see the Trans-Alaskaoil pipeline, That pipeline and the road thatparallels it are good examples of why the work youare doing in promoting the understanding of thearctic environment is so important. The oil pipelinewas built with private financing and goverrrment supervision. In that regard, it representsthe best our nation can offer the wrld: The initiativeand vision of individuals working toward aspecific goal like building a pipeline, and thecooperation and broader concerns of a governmentworking for the common good, like protecting theenvironment.This kind of approach to development of theArctic and Subarctic will be even more importantto the world in the future. In our state alone,we have millions of tons of coal and hard rockminerals that some day will have to be brought tomarket. To do the job right, we will require allthe knowledge you can give us on the complex phenomenoncalled permafrost. This is one reason whythe State of Alaska has joined the National Academyof Sciences in helping to sponsor this internationalconference. We know that the mrk youare doing and sharing with your colleagues is importantto our development as a state. As Governor,I also know that the mrk you are doing isimportant to the people who have called the Arctictheir home for thousands of yeara. The InupiatEskimos depend upon all kinds of mmmals, waterfowl,and fish to keep their culture alive as welas to pass that culture on to future generations.And make no mistake about it, the Inupiat are verydetermined that their culture not become extinct.ks a matter of fact, the Northwest Territories ofCanada will play host next week to the Annual CircumpolarConference, where the residents of allbut one arctic region will gather to renew theirnatural ties and fashion their common goals. "hatconference in Frobisher Bay is an important onefor the future of our state, and the arctic regionof Alaska.So, too, is this conference, because the engineeringand other studies that are a part ofyour wurk as scientists will play a central rulein future development. And unless that developmentgoes ahead on a sound environmental basis,the future of the Arctic and its people will bethreatened. I see no reasons why the futureshould be threatened for the arctic regions of theworld. With the talent that is assembled in thisroom and the determination of government and industryleaders to make sound practices and soundprojects happen, we can have rational economic developmentin the Arctic wlthout sacrificing eitherthe past or the future.To do this will require a coordinated a pproach among scientists, politicians, and laymen.AH an American, I am sad to say that my country isthe only polar nation without a coordinated effortto conduct the necessary scientific research inthe Arctic. But I an glad to report that we mayfinally be resolving the problem. As you mayknow, the Alaskan delegation to the U.S. Senateand House of Representatives has sponsored billsto create an Arctic Science Policy Council and anArctic Research Commission. We hope these billswill pass very soon, and that with than will comea commitment of money to bring the arctic sci-

34 1ences the coordination and prestige that I knowthey deserve. The State of Alaska has endorsedthe concept of both the House and Senate legislation,and I would encourage those of you here todayto let our Congress know how you feel, if youhaven't already.As Governor of Alaska, I know how my constituentsfeel about arctic research, because in thelast year the privately financed University ofAlaska Foundation has raised more than a quarterof a million dollars for arctic research. Forthat, we have many people to thank, including PaulGavora, Tom Miklautsch and Wiliam R. Wood, all ofFairbanks, and Attorney John Hughes and Bill Scottof Anchorage, who spearheaded the fund raisingdrive. That kind of financial commitment from individualAlaskans is positive proof that rn supportknowing more about the arctic regions. Thisresearch can benefit all of us, now and in theyears ahead. And you know, when you consider thewealth of our state's resources, our geographiclocation, and the potential markets we could serveon the Pacific Rim, the importance of the researchyou will be doing becomes all that more apparent.We need your knowledge because we are a maturingfrontier state, and in many ways e are like anemerging nation that is only vaguely aware of bothits potential and the problems that lie ahead.People like you will help us overcome the problems--people*o know that research and scientificinvestigation have made the mrld a better placeto live and can make it even better still in thefuture.It is an exciting time to be in Alaska, and Iam sure you will understand how fortunate I feelbeing governor at this point in our state's development.So, I again welcome you to Alaska, and Ihope you share some of that same excitement as youtravel throughout our state. Thank you so verymuch.TROY L. P6& - Ten years ago in Yakutsk, Siberia,discussion concerning the possibility of an InternationalPermafrost Association occurred. It wasa short discussion, but we realized such an organizationwas needed. Five years ago at Edmonton,our Canadian colleagues agreed to seriously lookinto the formation of such a group, and here toreport the latest events is Dr. Hugh French, headof the Canadian delegation.HUGH FRENCH - Mr. Chairman, ladies and gentlemen:An informal meeting was held yesterday among theofficial delegates from Canada, The People's Republicof China, the United States of America, andthe Soviet Union. I am very pleased to announcethat it was unanimously agreed to form an InternationalPermafrost Association. The four countriesjust mentioned will be founding members of thisassociation, and we encourage other nations toJoin it. Those who join within the next year willalso become founding members.The primary aim of the association will be toprovide for the on-going organization and coordinationof International Permafrost Conferences.This will be done through the Adhering NationalBodies. An International Secretariat will be establishedin Canada at the University of BritishColumbia. Professor J. Ross Mackay has agreed toserve as Secretary-GeneraLAt the meeting yesterday, Academician P.I.Melnikov of the Soviet Union accepted the positionof President of the new association, and ProfessorTroy L, P&d of the United States accepted the positionof Vice-president.Details concerning national and individualmemberships can be obtained from the Constitution,an outline of which will be available at the rearof the hall after this meeting [text follnrsl~ Iam sure that you will all join with re in wishing

342every success to the new association, which, Ishould emphasize, as Professor PLw6 has just done,is the culmination of several years of discussion.I believe that it is both timely and appropriate,particularly given the success of this andprevious international conferences on permafrost.Therefore, it-remains for me to congratulateAcademician Melnikov and Professor Pi& upon theirappointment of office, and to thank Professor Mackayfor accepting the position of Secretary-General.I am confident that under their very capableleadership and guidance, the future of the associationand the continuing development of permafrostscience and engineering are internationally assured.Thank you very much.TROY L. PgWtf - Thank you, Dr. French. We will nowhave a few closing remarks from the leaders of thenational delegations. We will hear first fromAcademician Melnikov of the USSR.P.I. MELNIKOV - Mr. Chairman, ladies and gentlemen:I participated in this fourth conference onpermafrost and in the third, and I was also one ofthe organizers for the second permafrost conference.I am a witness to an increase in the numberof scientists who are participating in permafrostrelatedresearch and also engineei-i-working inthis area. He are indeed very pleased by this becausethis will aid us in the very importanr taskahead of us in developing enormous territorieswhich contain some of our most valuable resources.I could mention, for example, that inYakutia, which contains almost 90% of all the diamondresources in our country, there is considerablediamond extraction activity. It also containslarge deposits of gold and other valuableminerals.As you probably know, approximately one-halfof all the gas and oil is being extracted fromwestern Siberia. Also, the Far North containsenormous coal reserves. The hydroelectric powerstations being constructed there are also extremelyproductive. As already mentioned, the developmentof these northern territories requires specializedtechniques and methods. We have already,at the present time, learned how to construct theequipment used to develop these territories. Weare now faced with the further problem of makingthe equipment less expensive.Again, I repeat that I am very pleased to seethat the number of people working in this disciplinehas increased. We think that this is goingto further the development of the entire science.I would like to especially thank the organizingcommittee for all of the efforts that it hasundertaken in order to organize and arrange forthe Fourth International Conference on Perma-Erost. To all of you personally, I would like toextend my best wishes for successful scientificactivities and for success in your personallives. Thank you for your attention.TROY L. Pdd - Thank you, Academician Melnikov.Now I would like to call on Professor Shi Yafeng,representing the People's Republic of China.SHI YAFENG - Mr. Chairman, ladies and gentlemen:First of all, I would like to congratulate you onthe great success of this international conferenceand on the founding of the International PermafrostAssociation. Congratulations to AcademicianMelnikov, the first President of the association,to Professor Troy L. P&6, the Vice-president ofthe association, and to Professor J. Ross Mackay,Secretary-General of the association.In this conference, the Chinese delegationpresented their papers, exchanged scientific ideason the study of permafrost, and learned a greatdeal. During this conference, the Chinese delegateshave been warmly hosted by the U.S. OrganizingCommittee, the University of Alaska, the Cityof Fairbanks, the State of Alaska, and especiallythe people of the United States and Alaska. Wefeel the friendship among the scientists and thepeoples. Thanks for all the help given to theconference from all aspects.In recent years, permafrost research has developedrapidly and much has been achieved. Therestill exist many problems to be dealt with, andmore new ones will develop by the time the oldones have been solved. Thus, we have a great dealof work to do in the days ahead. In China, thereis an old story. It tells us that an old manwished to move two mountains in front of hishouse. Therefore, he dug at the mountains everyday without stopping. When he died, his sons carriedon. And when those sons died, his grandsonstook over the job. Finally, the two great mountainswere moved away. I am fully convinced thatin the next interval, with the cooperation of allthe scientists of permafrost in all the countries,we will surely solve the problems of permafrost.Finally, I sincerely wish all the delegates, allthe members of this conference, health and happiness.Thank you very much.TROY L. P h f - Next, we will hear from Dr, JerryBrown, representing the United SKates.JERRY BROWN - On behalf of our Committee on Permafrost,I would like to thank you again for attendingthe conference. 1 believe the count, as ofthis morning, was Khat more than 950 individualshave participated in various events of Khe conference,and that does not include the tremendoussupport staffs that have put the whole conferencetogether here in Fairbanks. 4a you know, the publishedrecord of the conference is already quitesubstantial. I would like to remind you that thepapers will be printed and distributed in a largevolume before the end of the year. So you have agreat deal of reading ahead of you.Some 140 people will be leaving tomorrow onfield trips throughout Alaska and into the CanadianNorthwest. I wish you good weather and interestingexperiences. We are all looking forwardto seeing you at the fifth conference, at whichtime some of us will have an opportunity to relax,I would like to thank you again. And to allthe visitors: have a safe and enjoyable journeyhome. Thank you.TROY L. P#d - Thank you, Jerry.Hugh French of Canada.Gnd now for Dr.

34 3HUGH FRENCH - Mr. Chairman, ladies and gentlemen:I speak on behalf of all those Canadians who haveparticipated in this conference. I would like tosay that w have found it extremely beneficial toour own understanding of permafrost conditions.We have seen a very smooth and highly organizedconference. We appreciate fully the magnitude ofthe logistics behind all of this, and we want tocongratulate you upon the successful completion ofthis tremendous job. Mention was also made in theopening remarks of this conference on Monday ofCanadian participation in the review process andorganization of the conference. Let me say, Mr.Chairman, on behalf of all those Canadians, thatit was a pleasure to be so involved. Canada andthe United States have many common interests inthe North, and permafrost is central to many ofthem. We look forward to future cooperation andscientific exchange in the future. We also lookforward to maintaining our contacts with ourfriends in the Soviet Union. Permafrost anddrilling technology are but two of the number oftopics that have recently been agreed upon as beingareas of mutual technological and scientificexchange between our two countries. Finally, ithas been a pleasure to discuss permafrost problemswith our colleagues from other countries. We areparticularly impressed with the growth of permafroststudies in China, and we look forward tohearing more about these in the future. Therefore,Mr. Chairman, on behalf of all the Canadiandelegates, we thank you for organizing and holdingthis Fourth International Conference. Thank you.TROY L. Pdd - At this time, I would like to introduceDr. Kaare Flaate. Dr.Flaate is Chairmanof the Permafrost Committee of the Royal NorwegianCouncil for Scientific and Industrial Researchthat is based in Oslo. Dr. Flaate.KAARE FLAATE - Ladies and gentlemen: I am here inorder to present an invitation. But 1 think thatI will first start by making a confession. It wasonly after I arrived here Sunday afternoon that Iappreciated all the work that went into organizingthis conference. And that so affected me that Iconsidered turning around and going home. Well,there are always simple reasons that keep you inline, and X tell you I have two good reasons fornot leaving. First, 1 had an APEX airline ticket.and I could not return immediately. And secondly,I was what you would call "dead tired." And I amglad I stayed. It has been a pleasure to participatein the conference. 1 know I gained professionallyas wel as socially.We would like to invite you to Norway for thenext conference. I will give you two good reasons.One, somebody has to arrange the conference,and we feel that we also have obligationsfor international cooperation. We must do ourshare of the work. So much for the unselfishpart. Second, we believe that the whole countryhas much to gain by having the conference. Wewill gain a lot professionally and we will havethe pleasure of having visitors. So that was theselfish side.Let IW finish this brief talk by presentingthe official invitation for you.INVITATIONThe Norwegian Committee on Permafrostis pleased to act as host forThe Fifth International Conference on Permafrostin June 1988at the Norwegian Institute of Technologyin Trondheim, NorwayThe Norwegian Committee on Permafrost was appointedby the Royal Norwegian Council for Scientificand Industrial Research with the ah of promotingPermafrOSK research and technology. TheNorwegian Institute of Technology is well equippedfor and has long experience in handling conferences.The academic community at Trondheim has aprofessional background in permafrost problems.The city of Trondheim has a population of about130,000 and was founded by the Vikings in 997.The city has many interesting sights and is a naturalstarting point for excursions related to permafrostphenomena.TROY L. Pl?d - Academician Melnikov, new Presidentof the International Permafrost Association, willnow accept the invitation.P.1. MELNIKOV - Ladies and gentlemen: I think atthis time we should all extend our gratitude tothe Government of Norway for the opportunity toconduct the Fifth International Conference on Permafrostin Norway. I think that in connectionwith this it would be a very good idea to proposethat a second vice-president of the newly formedInternational Permafrost Association be ProfessorKaare Flaate, the representative of Norway. Ithink that al.1 of you will join us in supportingthe proposal to hold the next international conferencein Norway. We support this proposal.Again, permit me at Khis time to express myheartfelt gratitude to all of you for the honoryou have accorded me, to be the first president ofthe newly founded International Permafrost Association.I have already dedicated my entire life topermafrost studies. When I was still only a studentin the Leningrad Mining Institute, I spentthree years conducting research on the proposedBaikal-Amur Railroad, whose conotructlon is presentlybeing completed. Upon completion of mystudies, I was then assigned to activities in theAcademy of Sciences of the SovietAcademy of Sciences in turn sentUnion. Theme to work in thefar northern regions as the director of a scientificresearch institute. I spent three yearsthere in the Indigirke region, and then I spentthe next 23 years working in Yakutia, conductingscientific research and also as the director ofthe Yakutsk Permafrost Institute. At the sametime, for the last 13 years, I have been a representativeof the Academy of Sciences of the SovietUnion in Moscow. The Scientific Cryology Council,whose activities I participate in, in Moscow, isresponsible for organizing and coordinating allthe research projects carried out by both theacademic community and the industries throughoutthe entire Soviet Union. I anticipate that thenew activities that I will have to be carrying out

344as the president of the newly founded InternationalPermafrost Association will be quite difficult,since it is always difficult when a new associationor organization is founded. But again, Iwill exert all possible energies and talent to seethat the work carried out by our association willfurther all of the research in permafrost. Iwould like to thank you once again.TROY L. Pgd - Thank you, President Melnikov: Iam sure that all of you noticed the very largebanner proclaiming the Fourth International Conferenceon Permafrost, all four conferences, onthe wall in the Great Hall during the past week.I have now taken down this banner. In addition tothe conferences being proclaimed in three languages,there are the logos of the past four conferences.I think you remember this banner. Itis now my duty to pass this banner on to KaareFlaate, who will be in charge of it until the nextconference. Perhaps he will add another officiallanguage, and indeed another logo. Dr. Flaate,please accept this banner.You will be happy to know that we are nearingthe end of our plenary sessions. However, beforewe have our final statements, I have a pleasantduty. We are fortunate to have in the audiencethe oldest active investigator of permafrost inAlaska and probably North America. Here today tolisten to our deliberations is Professor Earl B,Pilgrim, first professor of Mining Engineering andMetallurgy of the University of Alaska. ProfessorPilgrim was one of the six original faculty of theAlaska Agricultural College and School of Mines(now the University of Alaska) when it opened itsdoors on Sec Itember 18. , 1922, Since 1926, he hasbeen actlvely mining in perennially frozen graveland bedrock and now operates an antimony mine inthe Kantishna District near Denali National Parkin the Alaska Range. Now in his nineties, ProfessorPilgrim has been actively working with permafrostfor 60 years. It is my pleasure to introduceProfessor Earl H. Pilgrim of Stampede Creek.Professor Pilgrim, would you please stand and behonored.I would like to call on Dr. Jay Barton, Presidentof the University of Alaska, and a generoushost of the conference for a closing statement.JAY BARTON - Dr. P€wwb, it has been a great honorand pleasure to have the Fourth International Conferenceon Permafrost here on the campus of theUniversity of Alaska at Fairbanks, We hope youall will return. Thank you.TROY L. P$We’ - We have now reached the end of theformal program of the Fourth International Conferenceon Permafrost, and it is a pleasure to notethat this has been the largest international conferenceon permafrost to date. I have been informedthat it was the largest and most complexconference ever held at the University of Alaskain Fairbanks.A8 Chatrman of the U.S. Organizing Committeefor the Fourth International Conference on Permafrost,I would like to thank you for participatingin the conference and wish you well on your returnjourneys. I now declare the Fourth InternationalConference on Permafrost closed.

34 5INTERNATIONAL PERMAFROST ASSOCIATIONBASIC PRINCIPLES OF THE CONSTITUTION(July 1983)The organizations referred to in the Constitution and By-laws are definedas follows:(1) Council is the governing body of the Association.(2) AdherinR National Body is a representative body, such as a nationalcommittee, designated by the appropriate authority to represent in the Councilof the Association the interests in permafrost of scientists and engineers of acountry .OBJECTIVETo foster the dissemination of knowledge concerning permafrost and promotecooperation among persons and national or international organizations engagedin scientific investigations or engineering work on permfrost.MEMBERSHIPMembership in the Association is through Adhering National Bodies. Thereshall be only one Adhering National Body per country.In countries where no Adhering National Body exists, an individual mayapply directly to the Association to take part in Association activities.OFFICERS OF THE ASSOCIATIONThe officers of the International Permafrost Associationare:(i) President(ii) Vice Presidents(iii) Secretary GeneralThe officers of the Association shall serve from the end of oneInternational Conference on Permafrost to the end of the next Conference.COUNCILThe Council shall consist of the President and two representatives fromeach Adhering National Body.The Council shall determine, with the adviceannual subscription fee to the Association.of the Secretary General, theThere will not be any fees unless approved by the Council.INTERNATIONAL CONFERENCE ON PERMAFROSTThe organization and financing arrangements of an International Conferenceare the responsibility of the Adhering National Body of the host country.AMENDMENTS TO CONSTITUTION AND BY-LAWSAlnendments to the Constitution and By-Laws nvly be proposed by an AdheringNational Body.

,Appendix A: Field TripsField trips were a major part of the FourthInternational Conference on Permafrost, and almosteveryone took advantage of either the extendedtrips, which took place immediately before or afterthe conference, or the local geological andengineering permafrost field trips, which tookplace during the conference,The local field trips permitted hundreds ofparticipants to observe permafrost and permafrostinducedconstruction problems as well as the relationshipof permafrost to vegetation in the Fairbanksarea.The five pre- and post-conference trips had atotal of 250 participants. A list of these tripsis as follows (the names of participants on eachtrip are indicated in Appendix D): A-1, AlaskaRailroad and Denall National Park; A-2, Fairbanksto Prudhoe Bay via the Elliott and Dalton Highways;B-3, Northern Yukon Territory and the MackenzieRiver Delta; B-4, Fairbanks to Anchoragevia the Richardson and Glenn Highways; and B-6,Prudhoe Bay and the Colville River Delta. Guidebooksfor these trips were available to all fieldtrip participants (see accompanying list).The carefully planned and executed fieldtrips and publications will be long remembered andwere appreciated by all the participants of thecone erence.Available GuidebooksPublished by Alaska Division of Geologicaland Geophysical Surveys, 794 UniversityAvenue, Basement, Fairbanks, Alaska 99701Guidebook 1: Richardson and Glenn Highways,Alaska. T.L. PdwP and R.D. Reger(eds. ), 1983, 263 p., $7.50.Guidebook 2: Colville River Delta, Alaska.H.3. Walker (ed.), 1983, 34 p., $2.00.Guidebook 3: Northern Yukon Territory andMackenzie Delta, Canada. H.M. French andJ.A. Heginbottom (eds.), 1983, 183 p.,$8.50.Guidebook 4: Elliott and Dalton Highways,Fox to Prudhoe Bay, Alaska. J. Brown andR.A, Kreig (eds. ), 1983, 230 p., $7.50.Guidebook 5: Prudhoe Bay, Alaska. S.E.Rawlinson (ed.), 177 p., $6.00.Guidebook 6: The Alaskan Railroad BetweenAnchorage and Fairbanks. T.C. Fuglestad(ed.), approx. 130 p.Oscar J. Ferrians, Jr,, ChairmanField Trips Commlttee34 7

Local Field TripsIntroductionOne of the main reasons for holding theFourth International Conference on Permafrost inFairbanks was that permafrost and its effect onman's activities in the North are well illustratedlocally. It is possible to see many permafrostphenomena and many permafrost-related constructionproblems within a few miles of the University ofAlaska (Fairbanks) campus.Therefore, among the highlights of the conferencewere the field trips in the immediateFairbanks area to examine engineering and geologicalaspects of permafrost. During the conference,three afternoons (Tuesday, Thursday and Friday)and tw evenings (Monday and Wednesday) were setaside for these trips. No technical sessions wereheld during those times. The trips were providedat no extra cost to the registrants, and publishedpermafrost information was issued to all of theparticipants.There were seven tours. Two different tourscovered the geological and vegetation aspects ofpermafrost and its relation to construction, andtwo covered the engineering aspects of permafrost,A special tour was scheduled to a permafrosttunnel, and one to a frost-heave facility.In addition to these bus trips, there was a selfguidedwalking tour (with brochure) to examinepermafrost features (thermokarst mounds) on theUniversity of Alaska campus.It is estimated that more than 500 registrantsparticipated in these local field trips andreceived published and unpublished scientific andengineering reports. Only draft copies were completedof the guidebooks to the permafrost andQuaternary geology of the Fairbanks area, and thepermafrost and engineering features. Therefore,all participants were provided with the followingpublications: 1) P6w6, T.L., 1958, Geology of theFairbanks (IF-2) Quadrangle, U.S. Geological Survey,Geological Quadrangle Map GQ-110, scale1:63,360, 1 sheet; 2) P&6, T.L., Ferrians, O.J.,Jr., Karlstrom, T.N.V., Nichols, D.R., 1965,Guidebook for field conference F central andsouth-central Alaska International Association forQuaternary Research, 7th Congress, Fairbanks,1965: Lincoln, Nebraska, Acadeuy of Science, 142p. (reprint 197, College, Alaska, Division of Geologicaland Geophysical Surveys); and 3) P&&,T.L., 1982, Geologic hazards of the Fairbanksarea, Alaska: Alaska Division of Geological andGeophysical Surveys Special Report 15, 109 p. Abrief descriptlon of the field trips is outlinedin this volume of the proceedings.AcknowledmentsThe two field trips on the geological-constructionaspects were organized and conducted byRichard D. Reger, Alaska Division of Geologicaland Geophysical Surveys, and Troy L. PLwi, ArizonaState University. They were very ably assistedduring the trip by the following members of theAlaska Division of Geological and Geophysical Surveysstaff: 1) Bus leaders: Rodney A. Combellick,Jeffrey T. Kline, and Stuart E. Rawlinson, and 2)Assistant bus leaders: Jeffrey H. Ewing, DuncanR. Hickmtt, Terry M. Owen, David A. Vogel, andChristopher F. Waythomas.Field trips emphasizing the engineering aspectsof permafrost were organized and carried outby A*J. Alter, Civil Engineering Consultant, andF,L. Bennett, University of Alaska. They wereably assisted at the many stope in the field bylocal members of the American Society of Civil Engineers.In addition, the organizers of the localfield trips appreciate the cooperation of Dan Eganof the Alaskan Gold Company in Fairbanks; AliceEbenal, vice president of E.V.E. Co., Inc.; officialsof the Northwest Alaska Pipeline Company incharge of the frost-heave facility in Fairbanks;and many others for enabling the local field tripsto be a success.Special acknwledgrwnt is made of the ColdRegions Research and Engineering Laboratory, especiallyPaul V. Sellnann, John Craig and BruceF. Brockert, for organizing and conducting themany trips that allowed hundreds of participantsto examine the tunnel cut into perennially frozen,organic-rich silt near Fox, north of Fairbanks,Permafrost in the Fairbanks AreaThe Fairbanks area is in the discontinuouspermafrostzone of Alaska, and perennially frozenground is widespread, except beneath hilltops andmoderate to steep south-facing slopes. Since1903, fires and disturbance of vegetation by landdevelopment have increased the depth to permafrostby 25 to 40 ft in many places, although much ofthe ground refroze after the surface was revegetated.Sediments beneath the floodplain are perenniallyfrozen as deep as 265 ft. Permafrostfrequently occurs as multiple layers of varyingthickness, and in many areas is not present. Unfrozenareas occur beneath existing or recentlyabandoned river channels, sloughs, and lakes.Elsewhere, layers of frozen sand and silt are intercalatedwith unfrozen beds of gravel. Depth to34 8

349EXPLANATION~ ~ and loess ; slopes g ~ ~ ~ ~Dredge tailingsGanarallv unfrozen where gravel: frozen wlthmodtrate to hlnh ice content where flne gralnedFlood-plain alluviumPermafrost with low Ice contentLower hillslope silt and creek valley silt0 Permfrost with high Ice contentThermokarst pite Pingo0 Field trip stopGeneralized permafrost mao of the Fairbanks area, Alaska, showing field trip stops.Modification of map prepared by T.L. Pdwwd.

350permafrost varies from 2 to 3 ft in undisturbedareas and is more than 4 ft on the slip-off slop le sof rivers. Ice in perennially frozen sedimentsbeneath the floodplain consists of granules thatcement grains. Large ice masses are absent.Permafrost in the retransported valley-bottomsilt in creek valleys and on lower hillslopes isthickest at lower elevations--up to at least 360ft near the floodplain of the Tanana-Chena Rivers.Permafrost in these sediments contains largemasses of clear ice in the form of horizontal tovertical sheets, wedges, and saucer- and irregular-shapedmasses. Ice masses are foliated (icewedges) and range from less than 1 ft to more than15 ft in length, Much of the ice is arranged in apolygonal or honeycomh network that encloses siltpolygons 10 to 40 Et in diameter. Perenniallyfrozen ground does not exist beneath steep southfacingslopes, but extends nearly to the summit ofnorth-facing slopes.The temperature of permafrost in the Fairbanksarea at a depth below the level of seasonaltemperature fluctuations (30 to 50 ft) is about31'P. If the vegetation cover is removed, therelatively warm, temperature-sensitive permafrostthaws (degrades). Thawing of permafrost in floodplainalluvium with low ice content results inlittle or no subsidence of the ground, but increek-valley bottom on lower slopes, thawing ofice-rich retransported loess (muck) results inconsiderable differential subsidence of the groundsurface.Although much permafrost in the area is probablyrelict (from colder Wisconsin-age conditions),it also form today under favorable circumtances. Pre-Wisconsin permafrost probably disappearedduring the widespread thawing in Sangamontime.Description ofNumbered Field Trip Stops*Stop 1 - WEST END OF COLLEGE HILLCollege Hill is a lcw bedrock hill coveredwith up to 80 Et of loess. The top and southsides are permafrost free and have long been thesites of agricultural fields and buildings of theUniversity of Alaska. From the top, a fine viewto the south shows the wide Tanana River floodplainwith the glacier-sculptured Alaska Range andMt. McKinley in the far distance.stop 2 - FARMERS LOOP "SINKHOLE"Almost all of Farrpers Loop Road crosses icerichpermafrost and continuing maintenance is necessaryto ensure a passable surface. In 1962,Farmers Loop Road was rerouted across ice-richpeat and organic silt between College Road and theeast entrance to the University of Alaska. Thisone-third-mile rerouting cost $170,000 (WoodrowJohanneon, Alaska Departrnent of Transportation andPublic Facilities, written comm., October 3,1977). Shortly after the subgrade was paved, dif -ferential settlement occurred because of thawingof the underlying ground ice and ice-rich peat andsubsequent compacting of the peat. In 1977, levelingof the road shoulders cost $5,000, and similarannual maintenance, including leveling withasphalt, has been necessary since 1974.The area has been called the Farraers Loopsinkhole because of the tremendous amount of 6ubsidencebring the past few years and continuedfilling with gravel and asphalt. A thickness ofup to 5 ft of pavement used as patching may bepresent in limited areas.In 1983, the area was painted white to promotereflection of solar radiation. In the winterof 1982-83, thermal heat tubes were installed atthe edge of the road on the west side in an attemptto freeze the ground beneath the highway andprevent further thawing and subsidence.Stop 3 - THEWKARST TOPOGWHY, GOLF COURSE, WARTRANSMITTER BUILDINGThe perennially frozen retransported loess atthe Fairbanks golf course and at the KFAR transmitterbuilding contains large ice wedges in a

35 1Stop 3. Troy P l d lecturing to grwp at KFARtransmitter station. The station had subsided 2to 3 ft by 1948; by 1983 it had subsided 4 to 5ft. The ground surface is now near the base ofthe windows.Stop 4. Hwse built in 1975 on ice-rich permafrost.(Photograph 3997 by T.L. P6w.5, 1977.)polygonal network. As the ground thaws, thermkarstpits and mounds form. Pits are steepwalled,5 to 20 ft deep, and 3 to 30 ft across.Broad mounds 50 to 100 ft in diameter and 2 to 4ft high have formed and are slowly growing higheras the ice continues to mlt. They are best displayedin the golf course, which was establishedin 1946 and is perhaps not only the world'B farthestnorth golf course, but the only one in whichthermokarst mounds and pits as natural hazardscause serious difficulty.The radio transmitter building and tower werebuilt in 1939. The building is of reinforced concrete,and, although the underlying ground hassettled considerably due to melting of ground ice,the foundation has not been seriously deformed.Ground subsidence became evident when the well inthe building began to "rise." The casing of thewell is frozen to 120 ft in permafrost, but thepump, which is set on top of the casing, continuesto "rise" above the floor. When it was 1 to 2 ftabove the floor, the well casing was cut off andreset at Eloor level. Contrary to popular opinion,the casing was not rising out of the ground;rather, the ground and building were sinkingaround the stable casing. The building has notbeen used as a transmitter station for severalyears, and stands partially subsided (3 to 5 ft)in the middle of the golf course surrounded bywell-developed thermokarst pits and mounds.Stop 4 - HOUSES DEFORMED BY UNDERLYING PERMAFROSTHouses hilt on the south-facing hillside atthis field trip stop on Fanners Loop Road are underlainwith unfrozen grbund and have excellentfoundations. Houses on the gentle lower slopes orflatlands here are underlain by ice-rich, perenniallyfrozen silt. Some homes with heated baserpentshave subsided in a disastrous way. For example,the foundation of one house was hilt in1974 and the house (see photograph) was Milt in1975. It was occupied for one year and vacatedduring the sumuer of 1977. By this time, evidencewas abundant that the underlying ice-rich pemfrostwas thawing. With the shifting of thehouse. vertical drain pipes dropped off, two ofthe basement doors and the front door were cut ofplumb, and the large concrete block front-doorstep had subsided. By 1983, the house had furthersubsided and was even mre severely distorted.The large concrete block steps at the front doorhad completely disappeared because of subsidence,and the level of the ground was up to the base ofthe front door. The basement room next to the garagewas severely cracked and the garage doorswere no longer functional, The house was not occupiedin 1983, except for a caretaker.Stop 5 - TRANS-ALASKA PIPELINE SYSTEMThe Trans-Alaska Pipeline System is the largestcompleted, privately funded construction effortin history. It was hilt in 1974-1977 and isdesigned to transport up to 2 million barrels ofcrude oil per day. The cost of constructing thepipeline was about $8 billion dollars. About $1billion of that amount was necessary to learn a-bout, combat, accommodate and otherwise work withthe perennially and seasonally frozen ground,which emphasizes the impact frozen ground had onthe cost of this major construction project.The pipeline transports warm crude oil, attemperatures up to 145"F, for about 800 miles fromthe North Slope of Alaska to the ice-free port ofValdez. Originally, the Trans-Alaska PipelineSystem was to be buried along most of the route.The oil temperature was initially estimated at158' to 176°F during full production. Obviously,such an installation would thaw the surroundingpermafrost, but, because such an enterprise hadnever beEore been undertaken, there was scantknowledge of the serious problem that would becreated by a warm-oil pipeline in frozen ground.

Stop 5. Elevated section of Trans-Alaska Pipelineat Engineer Creek, 5 miles north of Fairbanks.The pipe is insulated with 4 inches of resinimpregnatedfiberglass jacketed by galvanizedsteel. (Photograph 3986 by T.L. Phd, July 17,1977.)Thawing of the widespread ice-rich permafrostby a buried warm-oil line could cause liquificationand loss of bearing strength, thus producingsoil flow and differential settlement of the line.The greatest differential settlement could occurin areas of ice wedges. About half of the pipelinewas built above the ground because of thepresence of ice-rich permafrost.Although the elevated pipeline successfullydischarges its heat into the air and does not directlyaffect the underlying permafrost, otherfrozen ground problems must be considered. Theabove-ground pipe is placed on a cross beam installedbetween steel vertical-support members(pilings) placed in the ground. The 120,000 vertical-supportmembers used along the pipelineroute are 18-in.-diameter steel pipes that aresubject to frost heaving. To eliminate frostheaving, each steel pipe is frozen firmly into thepermafrost using a thermal device that is installedin the pipe. The device consists of metaltubes filled with hydrous ammonia that becomes agas in winter and rises to the top of the tubes.In the cold atmosphere it liquefies, running downthe pipe and thereby chilling the ground wheneverthe ground temperature exceeds the air temperature.The devices are non-mechanical and self-operating.Aluminum fins on top of the steel pilespermit rapid dispersal of heat. Both above-groundand below-ground construction modes for the pipelinesare used in the Fairbanks area.Stop 6. Local. field trip participants examininghuge ice wedges in perennially frozen retransportedloess of Wisconsin age near Fairbanks, Alaska.Stop 6 - PLACER GOLD MINE IN PERENNIALLY FROZENGROUNDPlacer gold lying at the base of perenniallyfrozen stream creek gravels was discovered in 1902about 16 miles north of Fairbanks. Within a fewyears the region became one of the greatest goldproducingregions in Alaska. Early placer miningused underground methods, but by the early 1920'smost of the richer deposits were exhausted. Inthe middle 20's a revival of mining in the Fairbanksgold region was stimulated by the initiationof large-scale operations with huge gold dredgesand hydraulic stripping of the overlying ice-richfrozen silt. Placer gold mining in the area wasessentially terminated in 1964 with the closingdown of the last dredge. However, small-scalemines still operate.Gold in the areas generally lies on bedrockand is overlain by 3 to 10 ft of perennially frozengravel. Overlying this is 100 to 300 ft ofperennially frozen, ice-rich retransported loess.This barren silt must be removed and the gravelthawed before the gold can be extracted. Untiltoday, the removal of the overlying frozen retransportedsilt was done by washing away theground with water under pressure through giant hydraulicnozzles.At the E.V.E. Co. Mine at Stop 6, the 45 ftof overlying perennially frozen, ice-rich silt wasremoved during the winter using huge mechanicaltractors (bulldozers), and frozen silt blocks were

pushed to one side. The frozen gravel, 25 ftthick, was then removed.in the summertime withmechanical equipment. The gold-rich gravel isprocessed through a screen and sluice box and thegold recovered.3The removal of 300,000 yd of perenniallyfrozen ice-rich silt created excellent exposuresof late Pleistocene and Holocene frozen silt depositswith large, complex ice wedges. The largeice wedges are exposed in the Goldstream Formation,which is Wisconsin in age. Overlying theGoldstream Formation is the 5-ft-thick Holoceneretransported silt with no ice wedges.Stop 7 - THERMOKARST MOUNDS AND PITSMounds as much ,as 8 ft high and 40 ft in diameterand isolated thermokarst pits occur in thecultivated field on the downhill side of theroad. Removal of natural vegetation caused thawingof permafrost and melting of ice wedges.Stop 8 - SEASONAL STREAM ICINGS (AUFEIS)Where Goldstream Creek crosses Ballaine Road,icings are formed and are sites of study by scientistsfrom the University of Alaska. Aufeis beginsto accumulate at Goldstream Creek in earlyNovember and reaches a maximum thickness of about4 or 5 ft by March or April; it is completelymelted by the middle of May, The stream freezesto the bottom in the winter, causing water tooverflow and accumulate as thin layers of ice.Aufeis plugs the stream channel during springbreak-up, and melt waters are forced onto surroundingfloodplain surfaces. This type of floodingis unique to subarctic and arctic regions.Stop 9 - BUILDINGS DISTORTED BY GROUND SUBSIDENCESome of the homes built in this subdivisionare sited on perennially frozen ice-rich retransportedsilt. As the ground thaws from the heat ofthe houses, the buildings become distorted andeventually have to be removed.N Gold Hill353Stop 10 - THERMOKARST PITS AND MOUNDSThe best-developed mounds (with the best-documentedhistory in the Fairbanks area) are in afield on the gentle, north-facing slope at the Universityof Alaska experimental farm. The smoothfield was cleared of black spruce in 1908; by1922, pronounced individual and connected depressionsthat interfered with the operation of farmmachinery had formed. The field was then seededto pasture. By 1938, the mounds were 3 to 8 fthigh and 20 to 30 ft in diameter. In November1938, a bulldozer removed the upper part of everyhummock and filled each pit until the land surfacewas approximately uniform. The smooth surface existedfor nearly a year; by July 1939"nearly ayear 1ater"rregularities in the smooth surfacebegan to form. During succeeding years, thermokarstmounds formed as the ground surface subsidedover nelting ice. By 1947, mounds in the areathat had been graded in 1938 were as large and ashigh as those in the field that were not graded,The maximum height was 8 ft. Comparisons of 1938and 1948 aerial photographs reveal a similar sizeand shape for the mounds. A soil-auger probe onJuly 14, 1948, revealed no ice or frozen ground 9ft below the surface in one of the trenches. Paperbirch, willow, alder and various forbs ntrwgrow where black spruce once stood.Stops 11-12 - GOLD HILLAn exposure 5 ft long and 0.8 ft wide on GoldHill was created by placer gold mining operationsin 1949-53. Here is exposed a rather completestratigraphic section of Quaternary deposits.Thawing and slumping have now destroyed the details,but the 202-ft-thick section of Gold HillLoess is still present, as are the brown gravelsof Pliocene-Pleistocene age in the tailing piles.The top of Gold Hill is free of permafrost, butpermafrost occurs on the lower slope and in thevalley bottom of Cripple Creek. The organic-richGoldstream Formation with ice wedges is exposed onthe south side of the mining exposure. On theSStops 11 and 12. Stratigraphic section of the Gold Hill-CrippleCreek area 5 miles west of Fairbanks, Alaska, showing late Cenozoicformations and distribution of modern permafrost as exposed in placergold mining excavations. Ash bed UA 347 is approximately 500,000years old. Diagonally lined area represents existing permafrost.

354north side there exists a 200-ft-high cliff ofloess with only a small amount of permafrost nearthe top. Various volcanic ash layers have beenIdentified, and the one at the base of the exposure(see illustration) is about 500,000 yearsold. The type locality of the Gold Hill Loess isthe north wall of the Gold Hill mining cut.Stop 13 - ESTER-CRIPPLE CREEKS MINING AREAThe Ester-Cripple Creeks mining area has beenextensively mined for placer gold for about thelast 80 years. Two ages of gold exist, one associatedwith the older brownish gravel (CrippleGravel), which may be Pliocene-Pleistocene in age,and a younger placer, which is associated with thegreyish gravel (Fox Gravel) and is early Pleistocenein age. These gravels are overlain by thickdeposits of loess of Illinoian and Wisconsin age.Today, permafrost in the area is restrictedto the valley bottom of the creeks and is up to100 ft thick. This frozen ground fomd in Wisconsintime.Stop 14 - EVA CREEKThis placer gold mining excavation exposesexcellent examples of perennially frozen Pleistocenegravel and retransported loess with large icewedges .Stop 15 - BRIDGE OVER GOLDSTREAM CREEK ON GOLD-STREAM HIGHWAYGoldstream Creek is entrenched 12 ft into theretransported loess, and permafrost is at a depthof 27 Et below the bottom of the stream. On thesides of the creek, permafrost is from 1 to 10 ftdeep. Pilings at the south end of the bridge annuallysettled at a rate of about 2 inches peryear for several years after the bridge was builtin 1965. This movernent was arrested each winterand frost heaving raised the pilings up to half aninch. By 1974, total pier settlement reached 6inches and the bridge deck had to be raised.Stops 16-17 - OPEN-SYSTEM PINGOSOpen-system pingos are low, generally forested,ice-cored, perennial mounds, and several occurin the Fairbanks area. They develop where cold,subpermafrost or intrapermafrost water slowlyflows through an artesian system and finds its waynear the surface where it is blocked and freezes.Hydrostatic stress and the force of ice crystallizatianare relieved by doming of the near-surfacematerial, which is silt in the Fairbanks area.These mounds may grow to a height of 25 ft andthen rupture, with subsequent rnelting of the pingoice and collapse of the mound. A large collapsedpingo with a lake about 30 ft across is exposed atStop 16, and a small pingo with a white opruceaspengrowth at least 100 years old is formed atStop 17.Stop 18 - THERMOKARST MOUNDS AND PITSOn the downhill side of the Goldstream Highway,natural vegetation covering ice-rich permafrosthas been removed, with subsequent formationof thermokarst topography.Stop 19 - SOLAR-ASSISTED CULVERT-THAWING DEVICEHighway culverts In the Subarctic and Arcticare very susceptible to filling by ice in winter.Gradual ice accumulation causes damming of streamand spring waters, resulting in flooding and highwayicings. Traditional methods for keeping theculvert open so that water does nOK back up andESTER -CREEK "ESTER ISLAND" CRIPPLE CREEK I0 500 metersStop 13. Cross section 1 mile west of the confluence of Ester and Cripple Creeks 10 miles west of Fairbanks,Alaska, showing probable distribution of late Cenozoic sedients prior to their partial removalby gold mining operations. The lower part of the Fairbanks Loess, where it is overlain by the GoldstreamFormation, is termd Gold Hill Loess. Holocene Engineer Loess and the Keady Bullion Formation,as well as ice wedges in the Goldstream Formation, are omitted for siqlicity. The diagonally linedareas represent distribution of modern permafrost. Permafrost data, surface topography, top of graveland bedrock, and the fault are based on data from U.S. Smelting, Refining and Mining Company, Fairbanks,Alaska.

355form ice on the roadway have involved 1) pumpinghot water into the culvert; 2) using a steam generatorto force steam through the culvert; 3) usingelectrical heat tapes installed in the pipe;and 4) melting the ice in the pipes with an oilfiredbarrel stove.To reduce costs for thawing of ice and culverts,a maintenance-free, solarassisted culvertthawing device has been designed, constructed, andinstalled at this site. This system circulatesfluid in a closed-loop circuit through flat solarcollectorplates. Preliminary tests indicate thatthe device is feasible and is cheaper than othermethods of thawing culverts.Stop 20 - PERMAFROST EXPERIMENT STATIONThe Alaska Field Station of the Cold RegionsResearch and Engineering Laboratory (CRREL) onFarmers Loop Road was established by the Corps ofEngineers in 1946 to obtain information related toproblem of design and construction in permafrostregions. The station is built on retransported,perennially frozen, ice-rich silt overlying creekgravel. Permafrost is 126 ft thick but does notextend to bedrock. Groundwater flowing from thepermafrost-free slope on Birch Hill lies betweenpermafrost and bedrock and is under artesian pressure.Drilling in 1946 produced a flowing artesianwel that is nm capped. This was the firstmajor permafrost research field station in theUnited States and was active from 1946 to 1978.More recently, private companies and a state agencyhave utilized the area for short-term permafroststudies.The experimental area was used to verify conclusionsreached by theoretical and or laboratoryresearch, to observe results of constructionmethods on permafrost, and to investigate somecurrent empirical designs and rnethods of construction.Soue of the studies included the testing oftypes of pilings and piling-installation methodsfor structural support, testing anti-frost-heavingdevices, insulation of pavements, rate of permafrostthawing under natural vegetation cover,cleared areas, and artificial highway and airfieldtest sections.Stop 21 - RELOCATION OF THE STEESE HIGHWAYThe relocation of the Steese Highway in thelate 1970's placed the road over perennially frozen,retransported silt with large ice masses. Anopportunity was provided to conduct a geophysicalsurvey to locate ice masses prior to excavationwhen they were exposed. Much of the perenniallyfrozen, ice-rich silt is now removed; however,some still remains under the road, and thawing isoccurring.Stop 22 - PERMAFROST TUNNELThe only research tunnel in permafrost in thewestern world was built by the Cold Regions Researchand Engineering Laboratory (CRREL) near Foxin the early and mid-1960's. It enters a nearverticalsilt scarp left at the edge of the valleyby gold-mining operations. Tunneling was performedby a prototype continuous mining machine(Alkirk Cycle Mner) that had never before beenused in permafrost, When operating properly, themachine could cut as much as 7 ft of tunnel in anhour. The 360-ft-long tunnel is nm maintained byCRREL and the University of Alaska for permafroststudies and demonstration purposes.The tunnel is cut in retransported loess ofthe Goldstream Formation. It exposes ice wedgesas wel as mammal bones of Wisconsin age. Thetunnel is 5 to 7 ft high and the permafrost has atemperature of about 2S0-300F. The tunnel is nowchilled in winter by circulating cold outside airand in sumwr by mechanical refrigeration, especiallynear the opening. An inclined drift from themain tunnel extends downward through poorly sortedstream gravel into disintegrated schist bedrock,This 200-ft-long inclined drift reaches a depthabout 20 ft below the level of the main tunnel.The warm permafrost is subject to slow, continuousdeformation, which has been extensivelystudied in the tunnel. Deformation rates rangefrom 0.17 to 0.24 in. per week vertically and from0.07 to 0.029 in. per week horizontally, with thehighest rates in both directions occurring at therear of the main tunnel. However, sublimation ofpore ice may offset closure from deformation inthe main tunnel. Creep of permafrost is very noticeablein the room at the end of the inclineddrift, where measurement poles have been twistedand deformed.Stop 23 - FROST-HEAVE TEST FACILITYEnormous reserves of natural gas ate nowknown in arctic Alaska. It is proposed to transportthis gas through western Canada to the contiguousUnited States or to southern Alaska bypipeline. Recause oil or natural gas Warner than32'F transported through a buried pipeline thawsthe perennially frozen, ice-rich ground, it isplanned to transport the gas by refrigerating itto a temperature lower than 32V. A chilled gasline may become a problem in areas of discontinuouspermafrost and seasonally frozen ground. Inthese areas, the unfrozen ground will freezearound the cold pipeline, forming ice segregationsthat could seriously distort the pipe. The amountof frost heave depends upon the type of soil andthe moisture available. If the refrozen ice-richground thaws, there will also be loss of soilbearingstrength, resulting in soil instability.To understand fully the nature of the freezingof fine-grained moist sediment in the vicinityof the chilled gas pipeline, the Northwest AlaskanPipeline and the Foothills Pipelines Companies establisheda frost-heave test facility on Chena BotSprings Road near Fairbanks in August 1978, anddata collection began in March 1979. This testfacility is on perennially frozen, retransportedsilt with considerable ground ice. The activelayer is 1 to 4 ft thick and the silt is very SUSceptibleto frost action if water is available.At the test facility, various masures for controllingor minimizing frost heave are undertaken.'pwo of the most effective basic controlmeasures involve various desJgns of pipe insulationand selected materials that surround thepipe. There are ten buried sections of 48-in.-diameterpipe. Each section provides testing fordifferent design combinations.

356Stop 24 - UNDERGROUND UTILIDORSIn areas of rigorous climate, it is commn toput water, sewer, steam, telephone, and other servicelines in a subsurface structure that connectsall buildings and central power plants. In theArctic and Subarctic, this utilidor system is extensivelyused to protect water and sewer linesfrom freezing in seasonally or perennially frozenground.An extensive utilidor spatem was first usedin central Alaska during World War I1 constructionof military bases. It is also used at the Universityof Alaska as well as several cities and villages.Because considerable heat emanates fromutilidor systems, surrounding permafrost maythaw. Utilidors in Fairbanks are in perenniallyfrozen gravel with low ice content and have functionedwell. However, utilidors installed in frozenground with high ice ConKent have slumped,sagged, and ruptured as the ground thawed.Stop 25 - FAIRBANKS WATER SYSTEMPrior to 1953, the citizens of the City ofFairbanks were largely dependent for their watersupply on shallow to mid-depth wells into the gravelof the floodplain. Water from these privatewells was heavily mineralized or organic rich. Aprivately owned steam plant and small water systemserved a very limited downtom zone in the city.With rapid growth, it was necessary to establish alarge-scale mnicipal facility to provide electricity,telephone, and water services. Water suppliesin cities in the Arctic and Subarctic generallyrequire the use of heated utilidors, whichare very expensive. Low winter temperatures andpermafrost present special problem for a communitywater system.In 1953, a special type of water system wasdesigned and installed in the City of Fairbanks,and it has been successful for the last 30 years.The concept of this system has been copiedthroughout the North. It consists of a recirculating(looped) water-distribution system in whichwater, wartned by heat at the power plant, constantlymoves from the street to the house connectionand back.Stop 26 - DISPOSAL OF SOLID WASTE IN THE SUBARCTICDisposal of solid wastes is more difficult inthe Arctic and Subarctic than in temperate areas,in part because of the presence of seasonally andperennially frozen ground. Frozen ground complicateslandfill site excavation, decreases theavailability of unfrozen cover material, preventsor reduces the natural processes of decay and absorptioninto the soil system, and restricts movementof ground water. Because of frozen groundand for other reasons, mch of the solid waste inthe Fairbanks area is baled before being placed inthe landfill or transported for salvage. Volumereduction by baling and landfill disposal of compactedmaterial has several advantages: all typesof waste can be handled; it is possible to salvagesome material prior to baling; volume of waste isreduced; and the life of the landfill area isdoubled.Stop 27 - FAIRBANKS WASTEWATER TREATMENT FACILITYThe Fairbanks Wastewater Treatment Facilityis a regional facility that was completed in1976. It includes a central headworks for recep-Kion of wastes, biological treatment units servicedby an oxygen plant, clarifiers with provisionfor sludge return, chlorine chamber, outfallfor effluent discharge into the Tanana River, andan aerobic sludge digester and facilities forhandling and disposal of solid waste. The treatmentfacility is built on perennially frozenfloodplain gravel with low ice content.Stop 24. Concrete utilidor under construction at Port Wainwright near Fairbanks. Thls area is on theChena River floodplain and is underlain by perennially frozen sand and gravel with low ice content.(Photograph 139 by T.L. Pdwk, July 16, 1947J

357SELF

Extended Field TripsFIELD TRIP A-1: ALASKA RAILROAD/DF.NAI,INATIONAL PARK, JULY 14-16, 1983The participants were transported by a charteredtrain with a specially prepared open gondolacar, accessible at any time, that provided excellentvisibility for observation and photography.July 14:July 15:Alaska Railroad Station, Anchorage, toDenali Park StationUpper Knik Arm (photo stop)Test section of concrete tiesDramatic view of Mount Denali and othernearby peaks (photo and lunch stops)Hurricane Gulch BridgeLarge beaver dams and ponds on bothsides of tracks (photo stop)Denali Park StationMcKinley Chalets (dinner and overnight)Denali Park AreaSix-hour bus tour of part of Denali NationalPark (a.m.).Tour of Usibelli Coal Mine (p.m.>. Returnto Chalets (dinner and overnight)July 16: Denali Park Station to FairbanksField GuidesHealy Canyon (Nenana River Gorge): largelandslides and related maintenanceproblemTown of Nenana on the Tanana RiverGoldstream Valley, underlain by ice-richpermafrost (lunch stop)Insulated track sectionSiding from which to view fully automattampingmachine used to raise andalign trackFairbanksFrancis C. Weeks, Alaska RailroadT.C. Fuglestad, Alaska RailroadTed B. Trueblood, Alaska RailroadOscar J. Ferrlans, Jr., U.S. GeologicalSurveyJoe Usibelli, Usibelli Coal MineThe cooperation and logistical support of theAlaska Railroad and its staff are greatly appreciated.358

359FIELD TRIP A-2: FAIRBANKS TO PRUDHOE BAY,JULY 12-16, 1983July 12:July 13:July 14:July 15:July 16:Field GuidesFairbanks to Yukon RiverFox: permafrost tunnel and surroundingsWashington Creek overviewWickersham Doroe overview (lunch)Livengood areaness CreekYukon River Campground (dinner and overnight)BLM briefing on transportation corridorand archeologyYukon River to ColdfootHighway maintenance campRay River overviewNo Nam CreekFinger Mountain uplands (lunch)Old Man runwayArctic Circle (photo stop)Gobbler's Knob overview (comfortst at ion)South Fork Koyukuk (photo stop)Rosie CreekMarion Creek Campground (dinner andovernight)Coldfoot to Toolik LakeSukakpak Mountain: ice-cored mounds andKoyukuk River (comfort station)Scenic views of Brooks Range to AtigunPass (lunch)Glacier hike (optional)At igun ValleyPump Station 4 overviewToolik Lake (dinner and overnight)Toolik Lake to DeadhorseTour of Toolik Lake research areaSlope Mountain: ice-cored rmundaHappy Valley cut and erosion (lunch)Franklin BluffsCoastal plainDeadhorseKodiak oilfield camp (dinner andovernight)Deadhorse to FairbanksBus tour of Prudhoe Bay (east)SOHIO camp (lunch)Bus tour to Kuparuk River oilfieldARCO and SOHIO camps (dinner)Depart for Fairbanks by planeFox TunnelP.V. Sellmann, CRREL, GeologyJohn Craig, CRREL, PaleobiologyBruce E.Brockett, CRREL, DrillingElliott Highway to Yukon RiverLeslie Viereck, Forest Service, PlantEcologyHal Livingston, Alaska Department ofTransportation and Public Facilities,Engineering GeologyGlenn Johns, Formerly Federal HighwayAdministration, Historical and EnvironmentalEngineeringYukon RiverDavid Wickstrom, BLM, Management ofTransportation CorridorJohn Cook, BIM, ArcheologyYukon River - Prudhoe BayJerry Brown, CRREL, Permafrost, EnvironmentRay Kreig, Kreig & Associates, TerrainAnalysisMike Metz, GeoTec Services, Geotechnical,PipelineK.R. Everett, Ohio State University,Soils, Landf o mPat Webber, University of Colorado,Plant EcologyPalmr Bailey, Military Academy, PeriglacialLandf or-Len Gaydos, USGS, Landsat, LandcoverClassificationRichard Haugen, CRREL, ClimateAtigun PassParker Calkin, State University of NewYork, Glacial GeologyLeah Haworth, State University of NewYork, Glacial GeologyPrudhoe BayTony Kinderknecht, SOHIO, Oil Field ActivitiesSue Degler, SOHLO, Environmental ProtectionCaesar Barrera, ARCO, Public AffairsK.R. Everett, Ohio State University,Soils, GeomorphologyPatrick Webber, University of Colorado,Plant EcologyThe special logistics required to accomplishthe field trip were supported by funding from theAlyeska Pipeline Service Company and the Universityof Alaska Foundation (derived from a varietyof conference sponsors). The actual logisticswere provided through the University of Alaska'sLogistic Center under David Witt's supervision andwith the volunteer help of the Explorer Post47-Search and Rescue (Fairbanks). Pam Tinsley ofthe Logistics Center and Dianne Nelson of CRRELarranged many of the final details for the trip.

Participants in A-2 Field Trip1. Celia Brcwn2. Glenn Johns3. Louie DeGoes4. Jerry Brown5. Cheng Guodong6. Lorenz King7. G. Michael Clark8. Baerbel K. Lucchltta9. Shi Yafeng10. cui plijiu11. Ursee Bus&ardt12. Kaye t4aacLmmes13. Lori ereemstein14. Richard Meugen15. Arruro Corre16. Jaime Aguirre-Puente17. H. Makela 33. Alfred Jahn 49. Ernest Muller18. Philip Tilley 34. Henry Holt 50. Jim Hamilton19. Noel Potter 35. Steve Blasco 51. Ray Herman20. Edward Maltby 36. Linda Witt 52. Ray Kreig21. Guy Larocque 37. Boris Zamsky 53. Hal Livingston22. Michael Brown 38. Esa Eranti 54. Terrence Hughes23. Patrick Webber 39. Thora Thorhallsdottier 55. Martin Gamper24. Juerg Suter 40. Oekar Burghardt 56. Jim Scranton25. Vernon Rampton 41. Max Maisch 57. Horst Strunk26. Arno Semrnel 42. Kaye EveretK 58. William Barr27. Michael Metz 43. Colin Crampton 59. Donald Coulter28. Xu Bomeng 44. Liu Hongxu 60. Dionyz Kruger29. Thomas Osterkamp 45. Zhu Qiang 61. Barbara Gamer30. Wang Liang 46. Wilbur Haas 62. Morris Engelke31. Patricia McCormick 47. Brainerd bars32. Palmer Bailey 48. Leonard GaydosNot pictured: Kathleen Ehlig, DianneNelson

361FIELD TRIP 8-3: DAWSON CITY TO TUKTOYAKTUK4LONG THE DEMF'STER HIGHWAY, JULY 23-30, 1983July 23:July 24:July 25:Fairbanks to Dawson City via two DC-3aircraftThemes: Permafrost and vegetation relationshipsin discontinuous permafrost;Quaternary geology and history;Klondike goldfields and modern placermining; Dawson CityPeat plateau and fen complexToo Much Gold Creek: permafrost-vegetationrelations, and effects of aspectHunker Creek, Mayes Claim: permafrostexposure revealing ice wedges and icebodies within organic-rich "ruck";placer mining techniquesBear Creek: open system pingoLower Klondike Valley: old tailing, YukonDitch, historical aspectsDawson City (dinner and overnight)Sixtymile Highway: Dawson City to theYukon-Alaska international boundaryThemes: Regional geomorphology of theKlondike district; periglacial phenomenaand tundra on the Yukon PlateauMidnight Dome, Dawson City: panoraudcviewYukon River ferry crossing, Dawson CityKm 54: torsKm 103-106: Yukon-Alaska boundary, cryoplanationterraces and patternedground, solifluction and tundraLunch in fieldReturn: castellated torsDawson City overlook (photo stop)Yukon River ferry crossing, Dawson City(dinner and overnight)Dempster Highway: Dawson City to EaglePlain LodgeThemes: Glaciated and unglaciated terrain;the Ogilvie Mountains; rock gla-July 26:July 27:clers; seasonal frost mounds; periglacia1phenomena (tors, slopes)Rock Glacier, Ogilvie MountainsTombstone Mountain overlook: regionalgeomorphology (photo stop)North Fork Pass, Ogilvie Mountains: seasonalfrost moundsDempster Highway near Chapman Lake: maninducedthermokarstLunch in fieldEngineer Creek and Col: springs, hydrolology, slopesCastles' Hill, OgilvLe River Valley:springs, tors, slopesSeven Mile Hill, Dempster Highway:Ogilvie River and Wernecke Mountains(photo stop)Eagle Plain Lodge (dinner and overnight)Dempster Highway: Eagle Plain Lodge toInuvikThemes: Eagle River Bridge, engineeringand permafrost considerations; theArctic Circle; patterned ground (mudboils); the Richardson Mountains, alpinetundra and periglacial phenouena;hydrology and road construction, culverts,icingsEagle River Bridge, Dempster Highway:permafrost engineering and monitoringThe Arctic Circle: mud boils and patternedgroundIcing locations, Dempster HighwayRat Pass, Richardson Mountains: unglaciatedterrain, tundra conditions, solifluction, blockstreamr and patternedground, pedimentsLunch in fieldEastern Foothills, Richardson Mountains:view of forest fire south of Fort Mac-PhersonPeel River ferry crossingMackenzie River ferry crossing (ArcticRed)Inuvik (dinner and overnight)InuvikThemes: Soils and vegetation in continuouspermafrost; non-sorted circles;organic terrain; Mackenzie Deltaecosystems; construction and engineeringin Inuvik and adjacent areaCampbell Lake lookout: regional settingKm 711, Dempster Highway: earth hummcksand vegetationKm 737, Dempster Highway: insulated roadtest site, permafrost engineering andmonitoringKm 749, Dempster Highway: snow road testsite, vegetation responseKm 754, Dempster Highway: Gaynor Lake,impact of forest fire in 1968 upon activelayer, vegetation and terrainInuvik (lunch)CFS Inuvik: md hummocks, firebreaks andvegetation

362wedges, tundra terrain, field experimentsIbyuk pingoPeninsula Point: massive ground ice exposures,ice wedgesLunch in fieldILlisarvik drained lake experimentalsite, Richards Islands: field experimentsin permafrostJuly 30:Tuktoyaktuk to Inuvik and departure forEdmontonField Guidessoil and et^^^^^ ~~~~~e~ at ~ o r n ~ ~ ~ d ~ ~ ~ckenzfe Delta near 1n~"ik~ July 27s 1 ~ ~ ~ .Fairbanks to Dawson CityH.M. French, Univers ity of Ottawa~ ~ a ~ S.A. n Harris, ~ ~ UniversR.0, van Everdingen,ity of CalgaryEnvironment CanadaJuly 28:July 29:Oil pipeline test padBoat excursion to Bombardier Channel:Mackenzie Delta ecosystems, soils,vegetationInuvik (dinner and overnight)Inuvik to TuktoyaktukThemes: a.m., Continuation of previousday; p.m., Mackenzie Delta and Tuktoyaktuk:Permafrost terrain, polygons,ice wedges, pingos from the airInuvik Scientific Resource Centre, Departmentof Indian Affairs and NorthernDevelopment, Government of Canada:tour of facilities and introduction byScientific Manager, D.A. ShetstoneInuvik (lunch)Air Transect: Inuvik to TuktoyaktukPolar Continental Shelf Project BaseFacility, Tuktoyaktuk, Department ofEnergy, Mines and Resources, Governmentof Canada: dinner and welcome,Director, PCSP, G.D. HobsonTuktoyaktuk Village ice cellars: groundice and Quaternary historyTuktoyaktuk and the Pleistocene DeltaThemes: Pingos, massive groundice, iceSixtymile HighwayH.M. FrenchS.A. HarrisDawson City to Eagle Plain LodgeS.A. HarrisR.0, van EverdingenW.H. Pollard, University of OttawaEagle Plain Lodge to Arctic RedS.A. HarrisH.M. FrenchR.O. van EverdingenArctic Red to InuvikJ.A. Heginbottom, Geological SurveyCanadaC. Tarnocai, Agriculture CanadaInuvik to TuktoyaktukJ.A. HeginbottomC. TarnocaiH.M. FrenchJ.R. Mackay, University of BritishColumbiaof

363Participants inB-3 Field Trip1.2,3.4.5.6.7.8.9.10.Herbert LiedtkeRoger LangohrStuart HarrisBaerbel LucchittaJonas AkermanWayne PollardJean-Claude DionneJ.A. HeginbottomMing-Ko WooJohn Vitek11.12.13.14.15.16.17.18.19.20.Charles Tarnocai 21.Wayne Rouse 22.Rendel Williams 23,Philip Tilley 24.Irene Heyse 25.Hugh French 26.Paul Haesaerts 27.William Krantz 28.Kevin Gleason 29.Jeff VandenbergheRobert GunnMargaret KielyMatti SeppalaColin ThornJames WillisJohannes KarteFrancesco DramisLori GreensteinCharles Harris30.31.32.33.34.35.36.37.38.Eduard KosterWiliam BarrRay KreigElse KolstrupHarald SvenssonJohn KielyRoss MackayHans KerschnerHorst HagedornNot pictured: Esa Eranti, John Flory, Peter Hale, Michael Metz, James Neuenschwander, R.O.Van Everdingen, David Harry, Edwin Clarke

364FIELD TRIP B-4: FAIRB ANKS TO ANCHOR AGE,RICHARDSON AND GLENN HIGHWAYS, JULY23-27, 1983July 23:Fairbanks to Delta JunctionHarding Lake: investigation of lake onnorth side of the Tanana River held inby high level terracesBirch Lake: shallow late-Quaternary lakein a re-entrant of the Yukon-TananaUpland damned on the west side bysediments of the Tanana RiverTanana River Overlook: view of thebraided glacial riverSouth wall of road cut at top of hill atMile 292.6: examination of ice-wedgecasts and ventifactsShaw Creek Bluff: panorama of the AlaskaRange and the broad Tanana River Valley;terminal moraines of the Deltaand Donnelly advances are seen in thedistanceShaw Creek Road: road cut exposes weatheredbedrock, ventifacts, ice-wedgecasts, dune sand and loessJuly 24:Tanana River Bridge: confluence of theTanana River and the braided DeltaRiver and the crossing of the TananaRiver by the Trans-Alaska PipelineSystemJack Warren Road: well-developed ventlfactson the outwash fan of the DeltaadvanceDelta Junction to PaxsonFAA Station: overlook of the AlaskaRangeDelta morainesExamination of the delta moraine andoutwash of Donnel ly agePolygonal ground and ice-wedge castsDonnel ly tillNorth-central Alaska Range: crossing ofthe Richardson Highway by the Trans-Alaska Pipeline SystemExamination of Holocene moraines ofBlack Rapids Glacier: alternate methodsfor dating, including radiocarbon,stratigraphy, lichenometry and treering counting

3651.2.3,4.5.6.7.8.9.10.11.12.Participants in B-4 Field Trip (Photograph 4762 by T.L. P&d)Troy L. P&d 13. Ursee BurghardtN.P. Prokopovich 14. Ann Christina Bedegrcui Zhijiu 15. Kathleen EhligAndre Panua 16. Oskar BurghardtJim Bales17. Dave VogelArturo Corte 18. Heinz-Peter JonsShi Yafeng 19. Peggy SmithQui Guoqing 20. Henry HoltCheng Guodong 21. Takeei KoizumiZhou Youwu 22. Max MaischRichard Reger 23. Eric KarlstromBarbara Gamper24.'ew 25.26.27.28.29.30.31.32.33.34.Josef SvobodaJuerg SuterDixie BrmnLisa ClayGeorge StephensBrainerd Mears,Noel Potter, Jr.John BellGary ClayThomas BakerLiu Hongxu35. Martin Gamper36. James Walters37. Peter Bayliss38. Bjorne Bederson39. Gerhard SontagJr. 40. bare Flaate41, Julie Brigham42. Alfred Jahn43. Donald Hyers44. Peggy Winslw45. Keith Scoular

366July 25:July 26:July 27:Crossing of the Denali fault by theTrans-Alaska Pipeline SystemRainbow MountainActive rock glacierCulkana Glacier view at Richardson MonumentSummlt LakePaxson to Mile 50 on the Denali Highwayand returnAlaska Range panoramaRoad cut in small eskerWhistler Ridge: cryoplanation terracesitePalsasRoad cut through an eskerPaxson to Glennallen on the RichardsonHighwayFrost-rived granite block6 from rigorousWisconsin periglacial environment(near site of Meier Road House)View of Wrangell MountainsSimpson Hill road cut and Copper RiverbluffPermafrost problem on man-made structuresin GlennallenTolsona No. 1: mud volcanoGlennallen to Anchorage on the GlennHighwayOverlook of Matanuska GlacierMatanuska Glacier: exadnation of terminalice thrustingUpper Matanuska Valley (photo stop)Typical cross section through a crevasse-fillridgeView of western Chugach Mountains inthe Twfn Peaks areaLandslide in Anchorage created by 1964Great Alaska Earthquake; GovernmentHill SchoolField Guides (and Lecturers*)Troy L. Pgwwl, Arizona State UniversityWchard D. Reger, Alaska Division ofGeological and Geophysical Surveys,FairbanksDaniel E. Lawson, Cold Regions Researchand Engineering Laboratory"Randall G. Updike, Alaska Division ofGeological and Geophysical Surveys,Anchor age*The. following individuals provided specialassistance at Big Delta: Glen Chowning, Superintendentof Public Schools, furnished overnight accommodationsin the school gymnasium; and R.L.Dinger of the Cold Regions Test Center furnishedcots and blankets and assisted in other local arrangewnts.

367FIELD TRIP B-6: PRUDHOE BAY AND ARCTICCOASTAL PLAIN, JULY 23-31, 1983July 23: Fairbanks-Prudhoe BayFairbanks to Deadhorse (commercialflight)Kodiak CampSOH10 Base Camp (lunch)Putuligayuk RiverWeather PingoPutuligayuk River reservoir and gravelPitPutuligayuk River archeology siteWest DockKodiak Camp, Nabors Drilling (dinner andovernight)July 24 and 25:Abandoned road near Deadhorse kirport~arti€i~an~~ ~xaminin~an ice we^^^ and peat alongSagavanirktok River bridge; thaw gully the west~rn bluff of the ~a~a~irktok River on theand ice wedge6~hird day of the ~ i ~ e K ~ i ~ ~ ~ ~ by Uun- o t o ~Sagavanirktok River floodplain can Ai ~~~o~ t I 1ARC0 Prudhoe Bay operations centerFlaw Station 2Sand dunes between Drill Site 4 and EastDockFlaxman boulders in Lake bed northeastof East DockEast Dock: traverse north along beachPump Station 1Prudhoe MonurnentDrill Site 14Mount PrudhoeAfrica LakeKuparuk River, east side and bridgeThaw streamC-60 PingoKuparuk Oil Field; thaw gully andKuparuk C gravel pitOliktok DockKodiak Camp (overnight)July 26:Colville River Boat Trip, NechelikChannel (fly to and from)Nuiqsut and Nuiqsut AirfieidPutu ChannelTapped lake, eroding pingo, and thawlakesPeat banks, ice wedges, and polygonsGubik FormationTapped Lake and lake fillSlough entrance, w low vegetation, andturf-house siteKodiak Camp (overnight)July 26:Coastal-Plain Overflight andBarrowNorth Slope BoroughBarrow utilidorGravel pitArcheology sit eNaval Arctic Research LaboratoqBarrow spitAnchorage (via comnercial flight)

368Field Guides (and Lecturers*) :Stuart E. Rawlinson, Alaska Division ofGeological and Geophysical Surveys,LeaderDavid M. Hopkins, U.S. Geological SurveyDonald A. Walker, Institute of Arcticand Alpine Research*John Harper, Woodward-Clyde Consultants(presently Dobrosky Seatech Ltd.)*Beth Knol, Shell Oil Company*H. Jess Walker, Louisiana State University,Colville River Guidebook AuthorDuncan Hickmot t and Terry Owen (DGGS) ,Field trip assistantsARC0 Alaska, Inc., and Sohio Alaska PetroleumCompany arranged logistics and ground transportation,and representatives from these companies accompaniedthe field trip. Alyeska Pipeline ServiceCompany arranged tours of Pump Station 1,Shell Oil Company was enthusiastic and helpfulwith a proposed visit to an artificial-islanddrill site. Kodiak-Nabors, a subsidiary of Anglo-Energy, provided accommodations at their facilityat Prudhoe Bay. The North Slope Borough providedassistance with field-trip activities at Barrow,Alaska. Participants examine well head at Drill Site 7.

Appendix B: Formal ProgramMonday, July 18, 19838:30 - 1O:OO a.m.OPENING PLENARY SESSION10:30 a.m. - noonPanel Session: PIPELINES IN NORTHERN REGIONSO.J. Ferrians, Jr. (Chairman), U.S. GeologicalSurvey, USAH.O. Jahns, Exxon Production Research Co., USAE.R. Johnson, Alyeska Pipeline Service Co., USAA.C. Mathews, Office of the Federal Inspector,ANGTS, USAM.C. Metz, GeoTec Services, USA1:30 - 3:30 p.m.INVITED CHINESE SESSIONChair: T.L. P€wwb, Arizona State University,USAJ. Brown, Cold Regions Research andEngineering Laboratory, USAShi Yafeng and Cheng Guodong. A brief introductionto permafrost research in China.Li Yusheng, Wang Zhugui, Dai Jingbo, Cui Chenghan,He Changgen and Zhao Yunlong. Permafrost studiesand railroad construction in permafrostareas in China.Zhou Youwu and Guo Dongxin. Sone features of permafrostin China.THERMAI. ENGINEERING DESIGNChair: V. Lunardini, Cold Regions Researchand Engineering Laboratory, USAJ.C. Harle, Alyeska, USAJahns, H.O. and C.E. Heuer. Frost heave mitlgationand permafrost protection for a buriedchilled-gas pipeline.Walker, D.B.L., D.W. Hayley and A.C. Palwr. Theinfluence of subsea permafrost on offshorepipeline design.Cronin, J.E. Design and performance of a liquidnatural convection subgrade cooling system forconstruction on ice-rich permafrost,Zirjacks, W.L. and C.T. Hwang. Underground utilidoraat Barrow, Alaska: A two-year history.Reid, R.L. and A.L. Evans. Investigation of theair convection pile as a permafrost protectiondevice.PIPELINESChair: U. Luscher, Woodward-Clyde, USAA.I. Gritsenko, Research Institute ofGas Industry, USSRThomas, H.P. and J.E. FerreLl. Themkarst featuresassociated with buried sections of theTrans-Alaska Pipeline.Stanley, J.M. and J.E. Cronin. Investigations andimplications of subsurface conditions beneaththe Trans-Alaska Pipeline in Atigun Pass.Hanna, A.J., R.J. Saunders, G.N. Lem and L.Carlson. Alaska Highway Gas Pipeline Project(Yukon section): Thaw settletnent design approach.Carlson, L. and D. Butterwick. Testing pipeliningtechniques in warm permafrost.Heuer, C.E., J.B. Caldwell and B. Zamky. Designof buried seafloor pipe lines for permafrostthaw settlement.Mitchell, D.E., S.W. Laut, N.K. Pui and D.D.Curtis. Well casing strains due to permafrostthaw subsidence in the Canadian Beaufort Sea.ICE AND SOIL WEDGESChair: M. Seppiilii, University of Helsinki,FinlandJ.R. Mackay, University of BritishColumbia, CanadaCarter, L.D. Fossil sand wedges on the AlaskanArctic Coastal Plain and their paleoenvironrwntalsignificance.Black, R.F. Three superposed system of icewedges at McLeod Point, northern Alaska, mayspan most of the Wisconsinan stage and Holocene.Lawson, D.E. Ground ice in perennially frozensediments, northern Alaska.369

370Jahn, A. Soil wedges on Spitzbergen.Ferrians, O.J. Pingos on the Arctic CoastalPlain, northeast Alaska.4:OO - 6:OO p.m.THERMAL ANALYSISChair: L. E. Goodrich, National ResearchCouncil, CanadaC. E. Heuer, Exxon Production ResearchCo., USAOdom, W.B. Practical applications of underslabventilation system: Prudhoe Bay case study.Hildebrand, E.E. Thaw settlement and ground temperaturemodel for highway design in permafrostareas.Hromadka, T.V. 11, G.L. Guymon and K.L. Berg.Comparison of two-dirnensional domain and boundaryintegral geothermal models with embankmentf reeze-thaw field data.Zhao Yunlong and Wang Jianfu. Calculation ofthawed depth beneath heated buildings in permafrostregions.Lunardini, V.J. Thawing beneath insulated structureson permafrost.MECHANICS OF FROZEN SOILChair: R. Dunning, Sohio, USAT. S. Vinson, Oregon StateUniversity, USABaker, T.H.W. and G.H. Johnston. Unconfined compressiontests on anisotropic frozen soils fromThompson, Manitoba.Mahar, L.J., R. Wilson and T.S. Vinson. Physicaland numerical modelling of uniaxial freezing ofa saline gravel.Ladanyi, B. and H. Eckardt. Dilatometer testingin thick cylinders of frozen sand.PLEISTOCENE PERMAFROST CONDITIONSChair: A. Jahn, University of Warsaw, PolandL. Christensen, University of Aarhus,DenmarkHaesaerts, P. Stratigraphic distribution of periglacialfeatures indicative of permafrost Inthe Upper Pleistocene loesses of Belgium.Landohr, R.. The extension of permafrost in WesternEurope in the period between 18,000 and10,000 y. B.P. (Tardiglacial): Informtion fromSoil Studies.Svensson, H. Ventifacts as paleo-wind indicatorsin a former periglacial area of southernSweden.Kolstrup, E. Cover sands in southern Jutland(Denmark).Vandenberghe, J. Ice wedge casts and involutionsas permafrost indicators and their stratigraphicposition in the Weichselian.Lu Guowei, Guo Dongxin and Dai Jingbo. Basic characteristicsof permafrost in northwest China.REMOTE SENSING AND PLANETARY PERMAFROSTChair: J.A. Heginbottom, Geological Surveyof CanadaR.A. Kreig, R.A. Kreig & Associates,USAClifford, S.M. Ground ice in the equatorial regionof Mars: A fossil remnant of an ancientclimate or a replenished steady-state inventory?Morrissey, L.A. The utility of remotely senseddata for permafrost studies.Gurney, J.R., J.P. Omby and D.K. Hall. A comparisonof remotely sensed surface temperatureand biomass estimates for aiding evapotranspirationdetermination in central Alaska.Panel Session:Tuesday, July 19, 19838:30 - 10:30 a.m.ENVIRONMENTAL PROTECTION OFPERMAFROST TERRAINJ.E. Hemming (Chairman), Dames h Moore, USAM.C. Brewer, U.S. Geological Survey, USAH.M. French, University of Ottawa, CanadaN.A. Grave, Permfrost Institute, Yakutsk, USSRJ. Tileston, Bureau of Land Management. USAP.J. Webber, University of Colorado, USA10:30 a.m. - 12:30 p.m.THERMODYNAMICS AND TRANSPORT PHENOMENAChair: J.L. Oliphant, Cold Regions Researchand Engineering Laboratory, USAA.V. Sadovskiy, Foundations andUnderground Constructions, USSRHoriguchi, K. and R.D. Miller. Hydraulic conductivityfunctions of frozen materials.Yoneyama, K., T. Ishizaki and N. Nishio. Waterredistribution measurements in partially frozensoil by X-ray technique.Kay, B.D. and P.H. Groenevelt. The redistributionof solutes in freezing soil: Exclusion of solutes.Aguirre-Puente, J. and J. Gruson. Measurements ofpermabilities of frozen soils.McGaw, R.W., R.L. Berg and J.W. Ingersoll. An investigationof transient processes in an advancingzone of freezing.MECHANICS OF FROZEN SOILChair: S.R. Stearna, ASCE, Dartmouth College,USAR.K. Sdth, ARC0 Oil h Gas, USANelson, R.A., U. Luscher, J.W. Rooney and A.A.Stramler. Thaw strain data and thaw settlelnentpredictions €or Alaskan soils.

371Zhu Yuanlin and D.L. Carbee. Creep behavior offrozen silt under constant uniaxial stress.Vinson, T.S., C.R. Wilson and P, Bolander. Dynamicproperties of naturally frozen silt.Chamberlain, E.J. Frost heave of saline soils.Corapcioglu, M.Y, A mathematical model for thepermafrost thaw consolidation.MOUNTAIN AND PLATEAU PERMAFROSTChair: Shi Yafeng, Institute of Glaciologyand Cryopedology, PRCS.A. Harris, University of Calgary,CanadaCheng Guodong. Vertical and horizontal zonationof high-altitude permafrost.King, L. High mountain permafrost in Scandinavia.Qiu Guoqing, Huang Yizhi and Li Zuofu. Alpinepermafrost in Tian Shan, China.Haeberli, W, Permafrost-glacier relationships inthe Swiss Alps, today and in the past.Greenstein, L.A. An investigation of mid-latitudealpine permafrost on Niwot Ridge, ColoradoRocky Mountains, USA.EFFECTS OF MAN-MADE DISTURBANCESChair: L. Rey, Comitd Arctique International,SwitzerlandC.W. Slaughter, U.S. Forest Service,USAKershaw, G.P. Sow abiotic consequences of theCANOL Crude Oil Pipeline Project; 35 years afterabandonment.Klinger, L.P., D.A. Walker and P.J. Webber. Theeffects of gravel roads on Alaska ArcticCoastal Plain tundra.Komarkova, V. Recovery of plant communities andsummer thaw at the 1949 Fish Creek Test Well 1,arctic Alaska.Thorhallsdottir, T.E. The ecology of permafrostareas in central Iceland and the potentialeffects of impoundment.Linkins, A.E. and N. Fetcher Effects of surfaceappliedPrudhoe Bay crude oil on vegetation andsoil processes in tussock tundra.Collins, C.M. Long-term active layer effects ofcrude oil spilled in interior Alaska.PLANETARY PERMAFROSTChair: D.M. Anderson, State University ofNew York, USAM.C. Mlin, Arizona State University,USAFanale, F.P. and R.N. Clark. Solar system icesand Mars permafrost.Carr, M.H. The geology of Mars.bucchitta, B.K. Permafrost on Mars.Nummedal, D. Permafrost on Mars: Distribution,formation and geological role.Panel Session:Wednesday, July 20, 19838:30 - 10-30 a.m.DEEP FOUNDATIONS AND EMBANKMENTSN.R. Morgenstern (Chairman), University of Alberta,CanadaDing Chingkang, Northwest Institute, PRCD.C. Ewh, Alaska Department of Transportation andPublic Facilities, USAB. badanyi, Ecole Polytechnique, Montr8a1, CanadaF.H. Sayles, CRREL (formerly Office of the FederalInspector, ANGTS), USA10:30 a.m. - 12:30 p.m.ROADS AND RAILWAYS (THEW ASPECTS)Chair: G.H. Johnston, National ResearchCouncil, Canada0. Gregersen, Norwegian GeotechnicalInstitute, NorwayZarling, J.P., B. Connor and D.J. Goering. Airduct systems for roadway stabilization overpermafrost areas.Johnston, G.H. Performance of an insulated roadwayon permafrost, Inuvik, N.W.T.McHattie, R. and D.C. Esch. Benefits of a peatunderlay used in road construction on permafrost.Goodrich, L.E. Thermal performance of a section ofthe Mackenzie Highway.Esch, D.C. Evaluation of experimental design featuresfor roadway construction over permafrost.Zhang Shixiang and Zhu Qiang. A study of the calculationof frost heaving.FOUNDATIONSChair: R.W. Fadum, North Carolina StateUniversity, USAJ.W. Rooney, R6M Consultants, USAAndersland, O.B. and M.R. Alwahhab. Lug behaviorfor model steel piles in frozen sand.Penner, E. and L.E. Goodrich. Adfreezing pressureon steel pipe piles, Thompson, Manitoba.Dufour, S., D. C. Sego and N.R. Morgenstern. Vibratorypile driving in frozen sand.DiPasquale, L., S. Gerlek and A. Phukan. Designand construction of pile foundations in theYukon-Kuskokwim Delta, Alaska.Nottingham, D. and A.B. Christopherson. Drivenpiles in permafrost: State of the art.Manikian, V. Pile driving and load tests in permafrostfor the Kuparuk pipeline system.FROST MOUNDS AND OTHER PERZGLACIAL PHENOMENAChair: H. Svensson, University ofCopenhagen, DenmarkR.F Black, University ofConnecticut, USA

37 2Mackay, J.R. Pingo growth and sub-pingo waterlenses, western Arctic coast, Canada.Seppala, M. Seasonal thawings of palsas in FinnishLapland.Pollard, W.B. and H.M. French. Seasonal frostmound occurrence, North Fork Pass, OgilvieMountains, northern Yukon, Canada.Corte, A.E. Geocryogenic morphology at SeymourIsland, Antarctica: A progress report.Walton, D.W.H. and T.D. Heilbronn. Periglacialactivity on the subantarctic island of SouthGeorgia.EFFECTS OF MAN-MADEAND NATURAL DISTURBANCESChair: T.F. Albert, North Slope Borough, USAP. Duffy, Environment CanadaEbersole, J.J. and P.J. Webber. Biological decompositionand plant succession following disturbanceon the Arctic Coastal Plain, Alaska.Johnson, A.W. and B.J. Neiland. An analysis ofplant succession on frost scars, 1961-1980.Maltby, E. and C.J. Legg. Revegetation of fossilpatterned ground exposed by severe fire on theNorth York moors.Racine, C.H., W.A. Patterson TI1 and J.G. Dennis.Permafrost thaw associated with tundra fires innorthwest Alaska.Johnson, L. and L. Viereck. Recovery and activelayer changes following a tundra fire in northwesternAlaska.Shaver, G.R., G.L. Gartner, F.S. Chapin 111 andA.E. Linkins. Revegetation of arctic disturbedsites by native tundra plants.Panel Session: CLIMATE CHANGEAND GEOTHERMAL REGIMEJ. Pilon (Chairman), Department of Energy, Minesand Resources, CanadaCheng Guodong, Institute of Glaciology and Cryopedology,PRCJ. Gray, University of Montreal, CanadaT.E. Osterkamp, University of Alaska, USAM. Smith, Carleton University, CanadaFOUNDATIONSChair: O.B. Andersland, Michigan StateUniversity, USAV. Manikian, ARC0 Alaska, Inc., USANixon, J.F. Geothermal design of insulated foundationsfor thaw prevention.Wojcek, A., P.M. Jarrett and A. Beatty. Cold-mixasphalt stabilization in cold regions.Luscher, U., W.T. Black and J.P. McPhail. Resultsof load tests on temperature-controlled pilesin permafrost.Gregersen, O., A. Phukan and T. Johansen. Engineeringproperties and foundation designalternatives in marine Svea clay, Svalbard.Liu Hungxu. Calculation of frost heaving force inseasonally frozen soil.Cui Chenghan and Zhou Kaijiong. Experimentalstudy of the frost heave reaction.GROUND ICE AND SOLIFLUCTIONChair: G. Gryc, U.S. Geological. Survey, USAJ.H. Akerman, University of Lund,SwedenRampton, V.N., J.R. Ellwood and R.D. Thomas. Distributionand geology of ground ice along theYukon portion of the Alaska Highway GasPipeline north of Kluane Lake.Harry, D.G. and H.M. 'Fuench. The orientation andevolution of thaw lakes, southwest BanksIsland, Canadian Arctic.Reanier, R.E. and F.C. Ugolini. Gelifluction depositsas sources of paleoenvironmentalinformation.Gamper, M. Controls and rates of movement of 801-ifluction lobes in the eastern Swiss Alps.Ellwood, J. and J.F. Nixon. Observations of soiland ground ice in pipeline trench excavationsin the south Yukon.WATERSHED STUDIES IN PERMAFROST REGIONSChair: R.F. Carlson, University of Alaska,USAB.E. Ryden, University of Uppsala,SwedenSlaughter, C.W., J.W. Hilgert and E.H. Culp. Sumuerstreamflow and sediment yield from discontinuouspermafrost headwaters catchments.Drage, B., J.R. Gilman, D. Hoch and L. Griffiths.Hydrology of North Slope coastal plain streams.Woo, M., P. Marsh and P. Steer. Basin water balancein a continuous permafrost environment.Fliigel, W.A. Summer water balance of a high Arcticcatchment area with underlying permafrostin Oobloyah Valley, N. Ellesmere Island,N.W.T., Canada.PERMAFROST AND CLIMATEChair: S.A. Bowling, University of Alaska, USAXu Xiaozu, Institute of Glaciology andCryopedology, PRCRouse, W.R. Active layer energy exchange in wetand dry tundra of the Hudson Bay lowlands.Smith, M.W. and D.W. Riseborough. Permafrost sensitivityto climatic change.Harris, $.A. Comparison of the climatic and geomorphicmethods of predicting permafrostdistribution in western Yukon Territory.Nelson, F. and S.I. Outcalt. A frost index numberfor spatial predictions of ground-frost zones.Xu Xiaozu and Wang Jiacheng. A preliminary studyon the distribution of frozen ground in China.

3734100 - 6:OO p.m.INVITED SOVIET SESSIONChair: J.R. Kiely, Bechtel PowerCorporation, USAO.J. Ferrians, U.S. GeologicalSurvey, USAMelnikov, P.I. Major trends in the development ofSoviet permafrost research.Gritsenko, A. and Yu.F. Makoyon. Drilling and operationof gas wells in the presence of naturalgas hydrates.Zakharov, Yu.F., L.D. Koauklim and Ye.M. Naviosky.The impact of installation for the extractionand transport of gas on permafrost conditionsin western Sibera.Vyalov, S.S. Engineering geocryology in the USSR:A review.Sadovskiy, A.V. The construction of deep pile foundationsin permafrost in the USSR (a summary).Grave, N.A. Cryogenic processes associated with developmentsin the permafrost zone.Panel Session:Thursday, July 21, 19838:30 - 1O:OO a.m.FROST HEAVE AND ICE SEGREGATIONE. Penner (Chairman), National Research Council,CanadaR.L. Berg, Cold Regions Research and EngineeringLaboratory, USAChen Xiaobai, Institute of Glaciology and Cryopedology,PRCR.D. Miller, Cornel1 University, USAP.J. Williams, Carleton University, Canada10:30 a.m. - 12:30 p.m.FROST HEAVEChair: E.J. Chamberlain, Cold Regions Researchand Engineering Laboratory, USAHolden, J.T. Approximate solutions for Miller'stheory of secondary heave.Lovell, C.W. Frost susceptibility of soils.Akagawa, S. Relation between frost heave andspecimen length.Konrad, J.M. and A.R. Morgenstern. Frost susceptibilityof soils in terms of their segregationpotential.Rieke, R.D., T.S. Vinson and D.W. Mageau. Therole of specific surface area and related indexproperties in the frost heave susceptibility ofsoils.Chen Xiaobai, Wang Yaqing and Jiang Ping. Influenceof penetration rate, surcharge stress andgroundwater table in frost heave.EMBANKMENTS, ROADS AND RAILWAYSChair: C.W. Lovell, Purdue University, USAK. Flaate, Norwegian Road ResearchLaboratory, NorwayBell, J.R., T. Allen and T.S. Vinson. Propertiesof geotextiles in cold regions applications.Hayley, D.W., W.D. Roggensack, W.E. Jubien andP.V. Johnson. Stabilization of sinkholes onthe Hudson Bay railway.LaVielle, C.C., S.C. Gladden and A.R. Zeman.Nuiqsut Airport dredge project.Tart, R.G., Jr. Winter constructed gravel islands.Wang Liang, Xu Bowng* and Wu Zhijln. Propertiesof frozen and thawed soil and earth damconstruction in winter.PATTERNED GROUND AND ROCK STREAMSChair: A.E. Corte, Instituto Argentina deNevologia y Glaciologia, ArgentinaQiu Guoqing, Institute of Glaciologyand Cryopedology, PRCWalters, J.C. Sorted patterned ground in pondsand lakes of the High Valley-Tangle Lakesregion, central Alaska.Muir, M.P. The role of pre-existing, corrugatedtopography in the development of stone stripes.the Kunlun Shan, China.Hagedorn, H. Periglacial phenomena in arid regionsof Iran.Cui Zhijui. An investigation of rock glaciers inSadovsky, A.V. and G.I. Bondarenko. Creep of frozensoils on rock slopes.WATERSHED STUDIES IN PERMAFROST REGIONSChair: M.K.R.0,Woo, McMaster University, Canadavan Everdingen, Environment CanadaAshton, W.S. and R.F. Carlson. Predicting fishpassage design discharges for Alaska.Lewkowicz, A.G. Erosion by overland flow, CentralBanks Island, western Canadian Arctic.Chacho, E.E. and S.R. Bredthauer. Runoff from asmall subarctic watershed, Alaska.PERMAFROST GEOPHYSICSChair: K. Kawasaki, University of Alaska, USAG.D. Hobson, Polar Continental ShelfProject, CanadaCollett, T.S. Detection and evaluation of naturalgas hydrates from well logs, Prudhoe Bay, Alaska.Kay, A.E., A.M. Allison, W.J. Botha and W.J.Scott. Continuous geophysical investigationfor mapping permafrost distribution, MackenzieValley, N.W.T., Canada.Sinha, A.K. and L.E. Stephens. Deep electromagneticsounding over the permafrost terrain inthe Mackenzie Delta, N.W.T., Canada.Ehrenbard, R.L. , P. Hoekstra and G. Rozenberg.*Name omitted in Abstract Volume, p. 247.

31 4Transient e lectromagnet ic soundings for permafrostmaauinn. .. -Oliphant, J.L., A.R. Tice and Y. Nakano. WatermigraKion due to a temperature gradient in frozensoil.Pearson, C., S. Murphy, P. Halleck, R. Hermes, andM. Mathews. Sonic resistivity measurements onBerea sandstone containing tetrahydrofuran hydrates:A possible analogue to natural gashydrate deposits.Ray, R.J., W.B. Kran tz. T.N. Cai ne and R.D. Gunn.A mathematical model for patterned ground:Sorted polygons and stripes, and underwaterpolygons.Vitek, J.D. Stone polygons: Observations of surficialactivity.Pukuda, M. The pore-water pressure profile onporous rocks during freezing.GROUNDWATER IN PERMAFROSTEvening:BanquetChair:Zhu Qiang, Water Power ResearchInstitute, PRCGovernor Bill Shef f ield: Welcoming remarksS. Russell Steams, President, American Societyof Civil. Engineers: Keynote Speaker.Friday, July 22, 1983Panel Session:8:30 - 10:30 a.m.SUBSEA PERMAFROSTD.M. Hopkins and P.V. Sellmann (Chairmen), U.S.Geological Survey, and Cold Regions Researchand Engineering Laboratory, USAS.M. Blasco, Geological Survey of CanadaD.W. Hayley, EBA, CanadaS.A.M. Hunter, Geological Survey of CanadaH.O. Jahns, Exxon Production Research Co., USA10:30 a.m. - 12:30 p.m.EXCAVATIONS, MINING AND MUNICIPAL FACILITIESChair: R.D. Abbott, Shannon .& Wilson, USARooney, J.W. and J.H. Wellman. Fairbanks wastewatertreatwnt facility: Geotechnical considerations.Simpson, J.K. and P,M. Jarrett. Explosive excavationof frozen soils.Weerdenburg, P,C. and N.R. Morgenstern. Undergroundcavities in ice-rich frozen ground.Sun Yuliang. Deformability of canals due tofreezing and thawing.Ryan, W.L. Design considerations for large storageranks in permafrost areas.Williams, D. The stabilization of the Nanisivikconcentrator foundation.COLD CLIMATE ROCK WEATHERINGChair: H. Hagedorn, Federal Republic ofGermanyS. Kinosita, Hokkaido University, JapanAkermn, J. Notes on chemical weathering, KappLing, Spitsbergen.Hallet, B. The breakdown of rock due to freezing:A theoretical model.Hyers, A, So= spatial aspects of climate-dependentmechanical weathering in a high altitudeenvironment.Kane, D.L. and J. Stein. Field evidence ofgroundwater recharge in interior Alaska.Michel, F.A. Isotope variations in permafrostwaters along the Dempster Highway pipelinecorridor.Wright, R.K. Relationships between runoff generationand active layer development near Schefferville,Quebec.Price, J.S. The effect of hydrology on groundfreezing in a watershed with organic terrain,SUBSEA PERMAFROSTChair: G. Shearer, Minerals ManagementService, USAJ.A. Hunter, Geological Survey ofCanadaMorack, J.L., H.A. MacAuley and J.A. Hunter. Geophysicalmeasurements of the sub-bottom permafrostin the Canadian Beaufort Sea,Neave, K.G. and P.V. Sellmann. Seismic velocitiesand subsea permafrost in the Beaufort Sea,Alaska.Walker, H.J. Erosion in a permafrost-dominateddelta.Swift, D.W., W.D. Harrison and T.E. Osterkamp.Heat and salt transport processes in thawingsubsea permafrosr at Prudhoe Bay, Alaska.Melnlkov, P.I., K.F. Voitkovsky, R.M. Kamensky,I.P. Konstantinov. Artificial ice masses inarctic seas.Paterson, D.E. and M.W. Smith, Measurement of unfrozenwater content in saline permafrost usingtime domain reflectometry.ECOLOGY OF NATURAL SYSTEMSChair: H.W. Gabriel, Bureau of LandManagement, USAK. MacInnes, Department of IndianAffairs, CanadaViereck, L.A. and D.J. Lev. Long-term use offrost tubes to monitor the annual freeze-thawcycle in the active layer.Walker, D.A. A hierarchical tundra vegetationclassification especially designed for mappingin northern Alaska.Schell, D.M. and P.J. Zieman. Accumulation ofpeat carbon in the Alaska Arctic Coastal Plainand its role in biological productivity.

375Koizumi, T. Alpine plant community complex inpermafrost areas of the Daisetsu Mountains,central Hokkaido, Japan.Murray, D.F., B.M. Murray, B.A. Yurtsev and R.Howenstein. Biogeographic significance ofsteppe vegetation in subarctic Alaska.Van Cleve, K. and L.A. Viereck. A comparison ofsuccessional sequences following fire on permafrost-dominatedand permafrost-free sites ininterior Alaska.2:OO p.m.CLOSING PLENARY SESSIONPoster SessionsTuesday, July 19, 1983THERMAL ENGINEERING DESIGNAND THEW ANALYSISBlanchard, D. and M. Frdmond. Computing the cryogenicsuction in soils.Burgess, M., G. Lemaire and A, Dupas. Soil freezingaround a buried pipeline: Design of an experimentin a controlled environment facility.Kinney, T.C., B.W. Santana, D.M. Hawkins, E.L.Long and E. Yarmak, Jr. Foundation stabilizationof central gas injection facilities, PrudhoeBay, Alaska *Phillips, W.F. Applications of the fast Fouriertransform to cold regions engineering."Wexler, R.L. Diurnal freeze-thaw frequencies inthe high latitudes: A climatological guide.*Yarmak, E., Jr. and E.L. Long. Some considerationsregarding the design of two phase liquid/vapor convection type passive refrigerationsystems.SITE AND TERRAIN ANALYSIS AND PIPELINESBrockett, E. and D. Lawson. Shallow drilling inpermafrost, northern Alaska.Gill, J.D. and M.P. Bruen. Permafrost conditionsat the Watana Dam site.*Vita, C.L. Thaw plug stability and thaw settlementevaluation for arctic transportationroutes: A probabilistic approach.*FROST MOUNDS, GROUND ICE, AND PATTERNED GROUNDBailey, P.K.Periglacial geomorphology in theKokrine-Hodzana Highlands of Alaska. *Bowling, S.A. Paleoclimate inferences from permafrostfeatures: A meteorological point of view.Brown, J., F. Nelson, B. Brockett, S.I. Outcaltand K.R. Everett. Observations of ice-coredmounds at Sukakpak Mountain, south centralBrooks Range, Alaska.*Burn, C.R. and M.W. Smith. Thermokarst development:SOW studies from the Yukon Territory,Canada.Dionne, J.C. Frost-heaved bedrock features: Avaluable permafrost indicator.Douglas, G.R., J.P. McGreevy and W.B. Whalley.* Paper published in first Proceedings volume.Rock weathering by frost shattering processes.*Ellis, J.M., P.E. Calkin and M.J. Bruen. Rockglaciers of the east central Brooks Range,Alaska.Gregory, E.C. and C.W. Stubbs. A high-resolutiontechnique for measuring motion within the activelayer. *Harris, C. Vesicles in thin sections of periglacia1soils from north and south Norway.*Hughes, T.J. Downslope creep of unstable frozenground.Unosita, S. Analysis of boring cores taken fromthe uppermost layer in a tundra area.Mitter, P. Frost features in the karst regions ofthe west Carpathian Mountains.*Kreig, R.A. and A.R. Zieman. Ground ice exposedin the Barrow Utilidor.Nelson, G.E. Cryopediments in the Bighorn Canyonarea, southcentral Montana.Priesnitz, K. and E. Schunke. Pediraentation andfluvial dissection in permafrost regions withspecial reference in northwestern Canada.*Souchez, R.A, and R.D. Lorrian. UD and ale0composition of successively formed ice layers:Implications in permafrost studies.Taylor, R.B. Thaw processes in coarse sediwntbeaches, Soroerset and Bylot Islands, N.W.T.Whalley, W.B. Rock glaciers: Permafrost featuresor glacial relics?*PERMAFROST GEOPHYSICSKawasaki, K. and T.E. Osterkamp. Application ofelectromagnetic induction measurements topermafrost terrain.Kiefte, H., M.J. Clouter and B.L. Whiffen.Acoustlc velocities in structure I and I1 hydratesby Brillouin spectroscopy.King, M.S. The influence of clay sized particleson seismic velocity for Canadian Arctic permafrost.Parameswaran, V.R. and J.R. Mackay. Field measurementsof electrical freezing potentials inpermafrost areas."Walker, G.G., K. Kawasaki and T.E. Osterkamp. Useof D.C. resistivity measurement for determiningthe thickness of thin permafrost.Wednesday, July 20, 1983FROST HEAVECoulter, D.M. Predicting heave and settlement indiscontinuous permafrost.Guymon, G.L., R.L. Berg and T.V. Hromadka 11.Field tests of a frost heave model.*Jones, R.H. and K.J. Lomas. The frost susceptlbilityof granular materials."Kettle, R.J. and E.Y. McCabe. Mechanical stabilizationand frost susceptibility.Mageau, D.W. and M.B. Sherman. Frost cell designand operation.*McCabe, E.Y. and R.J. Kettle. The influence ofsurcharge loads on frost susceptibility.*Wood, J.4. and P.J. Williams. Stresses and moisturemovements induced by thermal gradients infrozen soils.

376MECHANICS OF FROZEN SOIL, MUNICIPALAND EMBANKMENTSJones, S.J. and V.R. Parameswaran. Deformationbehaviour of frozen and sand-ice materials undertriaxial compression. *Keyser, J.H. and M.A. Laforte. Road constructionthrough Palaa fields.Knutsson, S. Thaw penetration and thaw settlementstudies associated with the Kiruna to Narvikroad, Sweden.Mahoney, J.P. and T.S. Vinson. A mechanistic approachto pavement design in cold regions."Man, Chi-Sing. Ultimate long-term strength offrozen soil a6 the phase boundary of a viscoelasticsolid-fluid transition."Phukan, 4. Long-term creep deformation of roadwayembankment on ice-rich permafrost.*Retamal, E. Soroe experimental results on snowcompaction. *Retherford, R.W. Power lines in the Arctic andSubarctic: Experience in Alaska. *Schindler, J.F. Solid waste disposal, NationalPetroleum Reserve in Alaska.*PERMAFROST MAPS, PERMAFROST IN CHINA,PLEISTOCENE PERMAFROSTBell, J.W. and T.L. Pew& Mapping of permafrostin the Fairbanks area, Alaska, forurban-planning purposes.Christensen, L. The recognition and interpretationof in situ and remoulded till deposits inwestern Jylland, Denmark.*Craig, J.L., T.D. Hamilton and P.V. Sellmann.Paleoenvironmental studies in the CKRELpermafrost tunnel.Granberg, H.B., J.E. Lewis, T.R. Moore, P. Steer,and R.K. Wright. A report on a quarter centuryof permafrost research at Schefferville.Heginbottom, J.A. Problem in the cartography ofground ice:Canada. *A pilot project of northwesternHeyse, I. Phenomena of fossil permafrost in sandydeposita of the last glacial in Belgium.Karlstrom, E.T. Periglacial features and paleoenvironmentin the Flagstaff region, northernArizona.Kerschner, H. Late glacial paleotemperatures andpaleoprecipitation as derived from permafrost:Glacier relationships in the Tyrolean Alps,Austria. *Kuhle, M. Permafrost and periglacial indicatorson the Tibetan Plateau, from the HimalayanMountains in the south to the Quilian Shan inthe north (28-40'N).Liedtke, H. Periglacial slopewash and sedimentationin northwestern Germany during the Wiirm(Weichsel) glaciation.*Lusch, D.P. Late Wisconsinan patterned ground inthe Saginaw lowland of Michigan.Shi Yafeng and Mi Desheng. A comprehensive map ofsncw, ice and frozen ground in China(1:4,000,000).*Strunk, H. Pleistocene diapiric upturnings oflignites and clayey sediments as periglacialphenomena in central Europe.*Wayne, W.J. Paleoclimatic inferences from fossilpermafrost indicators in alpine regions."WATERSHED STUDIES AND GROUNWATER IN PERMAFROSTBuska, J.A. Tanana River monitoring and researchprogram.Corbin, S.W. and C.S. Benson. The thermal regimeof a small Alaskan stream in permafrostterrain. *Dean, K.G. Stream icing zones in Alaska.Hilgert, J.W. and C.W. Slaughter. Physical, biological,chemical and hydrologiccharacteristics of a subarctic stream system.Runchal, A.K. PORFREEZ: A general purpose groundwater flow, heat and mass transport model withfreezing, thawing and surface waterinteraction.Slaughter, C.W. Sncw and ice in Caribou-PokerCreeks research watershed, central Alaska.Stoner, M.G., F.C. Ugolini and D.J. Marrett.Moisture and temperature changes in the activelayer of arctic Alaska.*van Everdingen, R.O. and H.D. Allen. Ground movementsand dendrogeomorphology in a small icingarea on the Alaska Highway, Yukon, Canada."Thursday, July 21, 1983THERMODYNAMICS AND TRANSPORT PHENOMENAAND RAILWAYS (THERMAL ASPECTS)Berg, R.L. and LC. Esch. Effect of color andtexture on the surface temperature of asphaltconcrete pavement."Gori, F.A. A theoretical model for predicting theeffective thermal conductivity of unsaturatedfrozen soils. *Gosink, T.A. Gas pernability in and emissionsfrom permafrost.Nakano, Y., A. Tice, J. Oliphant and T.F. Jenkins.Soil-water diffusivity of unsaturatedsoils at subzero temperatures."Riseborough, D.W., M.W. Smith and D.H. Helliwell.Determination of the thermal properties of frozensoils. *FOUNDATIONS AND EXCAVATIONSMindich, A. Behavior of concrete strip foundationson thawed layer of clayey permafrost.*Takasugi, S. and A. Phukan. Excavation resistanceof frozen soils under vibrating cuttings."Keusen, H.R. and W. Haeberli. Site investigationand foundation design aspects of cable car constructionin alpine permafrost at the Chli Matterhorn,Wallis, Swiss Alps.*PERMAFROST AND CLIMATEBrigham, J.K. and G.H. Miller. Paleotemperatureestimates of the Alaskan Arctic Coastal Plainduring the last 125,000 years."Chatwin, S.C. Holocene temperatures in the UpperMackenrie Valley, determined by oxygen isotopeanalysis of peat cellulose.*Gosink, J.P., T.E. Osterkamp and K. Kawasaki. Evidencefor recent permafrost warming in Alaska.Gray, J.T., J. Pilon and J. Poitevin. Active layerstudies in northern Quebec: Towards a predictivemodel.

37 7Harrison, W.D. and S.A. Bowling. Paleoclimate lmplicationsfor arctic Glaska of the permafrostat Prudhoe Bay.Haugen, R.K., S. I. Outcalt and J.C. Harle. Relationshipsbetween estimated mean annual air andpermafrost temperatures in north-central Alaska.*Odasz, A.M. Climatic and edaphic influences ontree limit, upper Alatna River drainage, centralBrooks Range, Alaska.Prokopovich, N.P. Paleoperiglacial climate andhydrocompaction in California, USA.Ryden, B.E. and L. Kostov. Thawing and freezingin tundra soils.Taylor, A. , A. Judge and D. Desrochers. Shorelinerecession: Its effect on permafrost and thegeothermal regime, Canadian ArcticArchipelago. *Pilon, J., A. Taylor, A. Judge and J.T. Gray.Paleoclimatic reconstruction from boreholetemperatures.SUBSEA PERMAFROSTBlasco, S.M. and M.J. O'Connor. The nature anddistribution of shallow subsea acoustic permafroston the Canadian Beaufort ContinentalShelf.MacAuley, H.A., J.A. Hunter, S.E. Pullan, J.L.Morack, R.M. Gape and R.A. Burns. Evidencefor seasonal variation of nearshore subseabottompermafrost temperatures in the CanadianBeaufort Sea.Osterkamp, T.E. and W.D. Harrison. Thermal regimeof subsea permafrost.Rogers, J.C. and J.L. Morack. Permfrost studiesalong the northern Alaska coast using geophysicaltechniques.PLANETARY PERMAFROST AND REMOTE SENSINGBoothroyd, J.C. and B.S. Timson. The Sagavanirktokand adjacent river systems, eastern NorthSlope Alaska: An analog for the ancient fluvialterrains on Mars.*Gaydos, L. and R.W. Witmer. Mapping of arcticland cover utilizing Landsat digital data.*SSns, H.P. Permafrost-related types of largescaledissection and deformation of Martianlandscape. *Malin, M.C. and D.B. Eppler. Observations of Martianfretted terrain. *Mellor, J.C. Use of seasonal window for radar andother image acquisition and arctic lake regionman agemen t . *PERMAFROST TERRAIN AND ENVIRONMENTAL PROTECTIONEverett, K.R. An 11-year record of active layerthickness, Arctic Gas Test Facility, PrudhoeBay, Alaska.Freedman, B., J, Svoboda, C. Labine, M. Muc, G.Henry, M. Nams, J. Stewart and E, Woodley.Physical and ecological characteristics atAlexandra Fjord, a high arctic oasis onEllesmere Island, Canada."Gartner, B.L. Germination Characteristics of arcticplants."Greene, D.F. Permafrost, fire and the regenerationof white spruce at treeline near Inuvik,N.W.T. , Canada. *Hall, D.K., P.J. Camillo, R.J. Gurney and J.P.Ormsby. Quantitative analysis of the recoveryof burned areas in Alaska using remote sensing.Hettinger, L.R. Vegetation mapping for habitatand wetland assessment along proposed minetransportation routes, northwestern Alaska.Knapman, L. Reclamation of fire control lines onpermafrost sites in interior Alaska.MacInnes, K.L. Land use controls and environmntalprotection on permafrost terrain in N.W.T.Marion, G.M., P.C. Miller and C.H. Black. Cyclingof N-15 through tussock tundra ecosystems.Newbury, R.W. and G.K. McCullough. Shoreline erosionand re-stabilization in a permafrost-affectedimpoundment.*Senyk, J.P. and E.T. Oswald. Ecological relationshipswithin the discontinuous permafrost zoneof southern Yukon Territory."EXHIBITORSAlaska Uepartment of Transportation & PublicFa,cilitiesAlaska Division of Geological and Geophysical SurveysAmerican Society of Civil EngineersArctic Environmental Information and Data Center,University of AlaskaGrctic FoundationsAssociated Pile and Fitting CorporationCold Regions Research and Engineering LaboratoryDames and MooreERTEC, Inc.Geologial Survey of CanadaGeophysical Institute, University of AlaskaHarza EngineeringInstitute of Arctic and Alpine Research, Universityof ColoradoInstitute of Water Resources, University of AlaskaMagnetics of AlaskaMobile Augers and Research Ltd.National Aeronautics and Space AdministrationNational Research Council, CanadaR.A. Kreig & Associates, Inc.3M CompanyTopp EngineeringUnited States Geological SurveyWorld Data Center A for Glaciology

Appendix C: Committees and ReviewersU.S. ORGANIZING COMMITTEEU. Luscher, Woodward-Clyde ConsultantsR.D. Miller, Cornell UniversityT.L. P&w.6* (Chairman), Arizona State UniversityT.E. Osterkamp, University of AlaskaG.E. Weller* (Vice-chairman), University of AlaskaA. Phukan, University of Alaska, AnchorageA.J. Alter, Technical Council on Cold Region6 Engineering,ASCEJ. Barton, University of AlaskaFIELD TRIPS COMMITTEEJ. Brown*, Cold Regions Research and EngineeringLaboratoryO.J. Ferrians, Jr. (Chairman), U,S. Geological0.J. Ferrians, Jr., U.S. Geological SurveySurveyH.O. Jahns, Exxon Production Research CompanyA,J, Alter, Technical Council on Cold RegionsJ.R. Kiely, Bechtel CorporationEngineering (ASCE)A.H. Lachenbruch, U. S. Geological SurveyF.L. Bennett, University of AlaskaR.D. Miller, Cornell UniversityJ. Brown, Cold Regions Research and EngineeringR.D. Reger, Alaska Division of Geological and Geo- Laboratoryphysical SurveysH.M. French, University of OttawaA.L. Washburn, University of WashingtonG.E. Johns, City of JuneauJ.H, Zumberge, University of Southern CaliforniaT.L. Pbwi, Arizona State UniversityL. DeGoes, FICOP SecretaryS.E. Rawlinson, Alaska Division of Geological and* Member Executive CommitteeGeophysical SurveysR.D. Reger, Alaska Division of Geological and GeophysicalSurveysL. Sweet, Alaska Department of Transportation andPAPER REVIEW AND PUBLICATIONS COMMITTEEPublic FacilitiesH. J. Walker, Louisiana State UniversityR.D. Miller (Chairman), Cornell UniversityF.W. Weeks, The Alaska Railroad, Federal RailroadD.M. Anderson, State University of New York, Buf-AdministrationfaloR.P. Black, University of ConnecticutJ.M. Boyce, NASAFINANCE AND ADVISORY COMMITTEER.F. Carlson, University of AlaskaH.M. French, University of OttawaJ. Barton, University of AlaskaJ. Dennis, U.S. Park ServiceD.R. Brown, University of AlaskaL.E. Goodrich, National Research Council of CanadaJ.R. Kiely, Bechtel CorporationW.D. Harrison, University of AlaskaT.L. Piwi, Arizona State UniversityH.0. Jahns, Exxon Production Research CompanyG.E, Weller, University of AlaskaC.W. Lovell, Purdue University (ASCE)V. Lunardini, Cold Regions Research and EngineeringLaboratory (ASME)LOCAL ARRANGEMENTS COMMITTEE - FAIRBANKSL.A. Viereck, U.S. Forest Service, AlaskaT.S. Vinson, Oregon State UniversityW.M. Sackinger (Chairman), University of AlaskaJ.R. Williams, U.S. Geological Survey, Menlo Park G.E. Weller, University of AlaskaL. DeGoes, SecretaryR.D. Abbott, Shannon and WilsonL. Bennett, University of AlaskaD.R. Brown, University of Alaska FoundationTECHNICAL PROGRAM COMMITTEE K. Coffer, University- of AlaskaJ. Cronin, Shannon and WilsonW.D. Harrison (Chairman), University of Alaska D.C. Esch, Alaska Department of Transportation andF,L. Bennett, University of Alaska Public FacilitiesJ. Brown, Cold Regions Research and Engineering W.D. Harrison, University of AlaskaLaboratory J. Hickey, University ofO.J. Ferrians, Jr., U.S. Geological Survey K. Kawasaki, University of AlaskaD.L. Kane, University of Alaska J. Miller, University of Alaska379

380D.M. Murray, University of AlaskaR.D. Reger, Alaska Division of Geological and GeophysicalSurveysP. Sackinger, Fairbanks, AlaskaL.H. Shapiro, University of AlaskaC.W. Slaughter, U.S. Forest ServiceL. Sweet, Alaska Department of Transportation andPublic FacilitiesL.A. Viereck, U.S. Forest ServiceLOCAL ARRANGEMENTS - ANCHORAGEW.C. Hanson (Chairman), Dams 6 MooreM.C. Brewer, U.S. Geological SurveyG. Dickason, University of AlaskaR. Dragnich, ExxonF. Fisher, Alyeska Pipeline Service CompanyP.S. Ford, Harza Engineering CompanyJ.E, Hemming, Dams & MooreD. Hickok, University of AlaskaLE. Johnson, Arctic Slope Consulting EngineersK. Krause, Alaska Division of Geological and GeophysicalSurveysJ. LaBelle, University of AlaskaR.I. Lewellen, Lewellen Arctic ResearchW. Parker, Parker Associates, Inc.L.D. Perrigo, Battelle Alaska OperationsJ.F. Schindler, Husky Oil NPRA OperationsC. Sloan, U.S. Geological SurveyJ.B. States, Battelle Alaska OperationsT. Swearingen, Chugach EngineersL.S. Underwood, University of AlaskaWorld Affairs CouncilREVIEWERS OF CONTRIBUTED PAPERSCivil EnnineeringB.D. Alkire, Michigan Technological University,Houghton, MichiganJ.D. Allen, ARCO Oil .5 Gas Company, Dallas, TexasA.J. Alter, American Society of Civil Engineers,Juneau, AlaskaO.B. Andersland, Michigan State University, EastLansing, MichiganT.H.W. Baker, National Research Council of Canada,Ottawa, CanadaR.L. Berg, CRREL, Hanover, New HampshireD.E. Bruggers, Harding-Lawson, Anchorage, AlaskaA.L. Burwash, A.L. Burwash Consulting Limited,Calgary, CanadaE.J. Chamberlain. CILREL, Hanover, New HampshireR.W. Christensen, Barding-Lwuson, Anchorage, AlaskaL.K. Clark, Salem, OregonB. Conner, ADOTPF, Fairbanks, AlaskaF.E. Crory, CRREL, Hanover, New HampshireR.L. Crosby, Bishop, CaliforniaD.C. Esch, ADOTPF, Fairbanks, AlaskaR.E. Fadum, North Carolina State University, Raleigh,North CarolinaK. Flaate, Norwegian Public Roads Administration,Molde, NorwayW.R. Galatiuk, Calgary, CanadaG.L. Guymon, University of California, Irvine,CaliforniaW.M. Haas, Michigan Technological University,Houghton, MichiganB. Hallet, University o f Washington, Seattle,WashinatonH.W. Hunt, Associated Pile 6 Fitting Corporation,Clifton, New JerseyL.E. Janson, VBB AB, Stockholm, SwedenP.M. Jarrett, Royal Military College, Kingston,CanadaH.L. Jessberger, Ruhr-University, Bochum, W. Ger--*YN.I. Johansen, University of Alaska, Fairbanks,AlaskaE.G. Johnson, ADOTPF, Anchorage, AlaskaR.J. Kettle, University of Aston, Birmingham, UnitedKingdomT.G. Krzewinski, Dames & Moore, Anchorage, AlaskaB. Ladanyi, Ecole Polytechnique, Montreal, CanadaK.A. Linell, Banover, New HampshireU. Luscher, Woodward-Clyde Consultants, WalnutCreek, CaliforniaL.J. Mahar, ERTEC Western Inc., tong Beach, CaliforniaA. Mahod, McClelland-EBA, Anchorage, AlaskaJ.P. Mahoney, University of Washington, Seattle,WashingtonR.W. McGaw, CRREL, Hanover, New HampshireL).I. Norum, University of Saskatchewan, Saskatoon,CanadaM. O'Rourke, RPI, Troy, New YorkE. Penner, National Research Council of Canada,Ottawa, CanadaA. Phukan, University of Alaska, Anchorage, AlaskaF. Pita, Bellevue, WashingtonB.H. Reid, Environmental Protection Agency, Corvallis, OregonR.G. Rein, Jr., Bellevue, WashingtonW.L. Ryan, Ott Engineering, Anchorage, AlaskaF.J. Sanger, Orange City, FloridaB.W. Santana, ARCO Alaska, Inc., Anchorage, AlaskaF.H. Sayles, CRREL, Hanover, New HampshireD.C. Sego, University of Alberta, Edmonton, CanadaR.G. Tart, Woodward-Clyde Consultants, Anchorage,AlaskaH.P. Thomas, Woodward-Clyde Consultants, Anchorage,AlaskaT.S. Vinson, Oregon State University, Coruallis,OregonJ.J. Walsh, Billings, MontanaP.J. Williams, Carleton University, Ottawa, CanadaA.F. Wuori, CRREL, Hanover, New HampshireR.N. Yong, McGill University, Montreal, CanadaW.L. Zirjacks, Frank Moolin 6 Associates, Inc.,Anchorage, AlaskaMechanical Ewineering (Heat Transfer)G. Abele, CRREL, Hanover, New HawshireD.M. Anderson, State University of New York, Buffalo,New York0.A. Ayorinde, Exxon Production Research Company,Houston, Texas8. Baker, National Research Council of Canada, Ottawa, CanadaR.L. Berg, CRREL, Hanover, New HampshireM. Burgess, Energy, Mines and Resources, Ottawa,CanadaL.E. Carlson, Foothills Pipeline Limited, Calgary,CanadaE.J. Chamberlain, CRREL, Hanover, New Hampshire

38 1E.J. Couch, Mobil Research 6 Development Corporation, Dallas, TexasD.M. Coulter, Royal Military College, Kingston,CanadaF.E. Crory, CRREL, Hanover, New HampshireJ.L. Davis, Earthtech Research Limited, Baltimore,MarylandB. Dempsey, University of Illinois, Urbana, IllinoisL. Domaschuck, University of Manitoba, Winnipeg,CanadaS. Dufour, Geocon, Inc., Calgary, CanadaJ. Ellwood, Foothills Pipeline Limited, Calgary,CanadaD. Elrick, Department of Land Resources Science,Univ. of Guelph, CanadaT. Ersoy, Foothills Pipeline Limited, Calgary,CanadaD.C. Esch, ADOTPF, Fairbanks, Alaska0. Farouki, Queen's University, Belfast, NorthernIrelandM.G. Ferrick, CRREL, Hanover, New HampshireJ.W. Galate, Enertech Engineering and Research,Houston, TexasP. Gaskin, Queens University, Kingston, CanadaLE. Gold, National Research Council of Canada,Ottawa, CanadaL. Goodrich, National Research Council of Canada,Ottawa, CanadaP.H. Groenevelt, University of Guelph, Guelph,CanadaG.L. Gupon, University of California, Irvine,CaliforniaD. Harland, Dames & Moore, Golden, ColoradoR.K. Haugen, CRREL, Hanover, New HampshireF.D. Haynes, CRREL, Hanover, New HampshireL. Hayes, University of Texas, Austin, TexasH.N. Haynoe, Land Resource Research Inst., CentralExp. Farm, Ggriculture Canada, Ottawa, CanadaJ.A. Heginbottom, Geological Survey of Canada, Ottawa,CanadaC.E. Heuer, Exxon Production Research Company,Houston, TexasS.W. Hopke, Exxon Research and Engineering, FlorhamPark, New YorkC,T, bang, EBA Engineering Consultants Limited,Edmonton, CanadaY.W. Jam, Agriculture Canada Research Station,Swift Current, CanadaT.C. Johnson, CRREL, Hanover, New HampshireG.H. Johnston, National Research Council of Canada,Ottawa, CanadaA. Judge, Energy, Mines and Resources, Ottawa,CanadaB.D. Kay, University of Guelph, Guelph, CanadaM. King, University of California, Berkeley, Cali-EorniaJ.M. Konrad, National Research Council of Canada,Ottawa, CanadaJ.F. Lea, Amoco Production Company, Tulsa, OklahomaY. Lee, University of Ottawa, Ottawa, CanadaS. Lin, Sir George William Campus, Montreal, CanadaE.F. Lobacz, Hanover, New HampshireE. Long, Arctic Foundations, Inc., Anchorage,AlaskaV.J. Lunardini, CRREL, Hanover, New HampshireL.J. Mahar, Earth Technology Corporation, LongBeach, CaliforniaD.W. Margeu, R&M Consultants, Inc., Fairbanks,AlaskaR.W. McGaw, CRREL, Hanover, New HampshireE.C..McRoberts, Hardy Associates Limited, Calgary,CanadaR.D.,Hller, Cornel1 University, Ithaca, New YorkN.R. Morgenstern, Edmonton, CanadaY. Nakano, CRREL, Hanover, New HampshireJ.F. Nixon, Hardy Associates Limited, Calgary,CanadaD.1. Norum, University of Saskatchewan, Saskatoon,CanadaJ.L. Oliphant, CRREL, Hanover, New HampshireK. O'Neill, CRREL, Hanover, New HampshireP.H. Oosthuizen, Queens University, Kingston, CanadaT.E. Osterkamp, University of Alaska, Fairbanks,E.AlaskaPenner, National Research Council of Canada,Ottawa, CanadaG. Phetteplace, CRREL, Hanover, New HampshireA. Phukan, University of Alaska, Anchorage, AlaskaW.P. Quinn, CRREL, Hanover, New HampshireR.L. Reid, University of Texas, El Paso. TexasW.R. Rouse, McMaster University, Hamilton, CanadaD. Shields, University of Manitoba, Winnipeg, CanadaW. Slusarchuk, R.M. Hardy & Associates Limited,Calgary, CanadaMew. Smith, Carleton University, Ottawa, CanadaJ.E. Sunderland, University of Massachusetts, Amherst,Massachusetts0. Svec, National Research Councilt awa , Canadaof Canada, Ot-S. Takagi, CRREL, Hanover, New HampshireA.R. Tice, CRREL, Hanover, New HampshireG.C. Topp, Land Resource Research Inst., CentralExp. Farm, Agriculture Canada, Ottawa, CanadaP.J. Williams, Carleton University, Ottawa, CanadaY.C. Yen, CRREL, Hanover, New HampshireRe Yong, McGill University, Montreal, CanadaJ.P. Zarling, University of Alaska, Fairbanks,AlaskaZhu Yuanlin, CRREL, Hanover, New Hampshire and Instituteof Glaciology and Cryopedology, pI(CGeophysical, Geothermal, and SubseaS.A. Arcone, CRREL, Hanover, New HampshireS.A. Bowling, University of Alaska, Fairbanks,AlaskaG.W. Brass, University of Miami, Miami, FloridaR.F. Carlson, University of Alaska, Fairbanks,AlaskaA.J. Delaney, CRREL, Hanover, New HampshireC. Economides, University of Alaska, Fairbanks,W.D.AlaskaHarrison, University of Alaska, Fairbanks,AlaskaR.K. Haugen, CRREL, Hanover, New HampshireJ.D. Hays, Lamont Geological Observatory, Palisades,New YorkC.E. Heuer, Exxon Production Research, Houston,P.TexasHoekstra, Geo-Physi-Con, Inc., Lakewood, CoLorad0D.M. Hopkins, U.S. Geological Survey, Menlo Park,CaliforniaW.A. Hoyer, Exxon Production Research, Houston,Texas

382J.A. Hunter, Geological Survey of Canada, Ottawa,CanadaA.S. Judge, Energy, Mines and Resources, Ottawa,CanadaG.V. Keller, Colorado School of Mines, Golden,ColoradoA.H. Lachenbruch, U.S, Geological Survey , MenloPark, CaliforniaR.I. Lewellen, Palmer, AlaskaA. Long, University of Arizona, Tucson, ArizonaU. Luscher, Woodward-Clyde Consultants, San Francisco,CaliforniaM.N. Nabighian, Newmont Overseas Explorer Limited,Tucson, ArizonaG. Neave, Northern Seismic Analysis, Echo Bay,CanadaG. Olhoeft, U.S. Geological Survey, Denver, ColoradoT.E. Osterkamp, University of Alaska, Fairbanks,AlaskaS.I. Dutcalt, University of Michigan, Ann Arbor,MichiganJ.C. Rogers, Michigan Technological University,Houghron, MichiganW.L. Sackinger, University of Alaska, Fairbanks,AlaskaP.V. Sellmnn, CRREL, Hanover, New HampshireC.W. Slaughter, USDA Forest Service, Fairbanks,AlaskaM.W. Smith, Carleton University, Ottawa, CanadaA.E. Taylor, Energy, Mines and Resources, Ottawa,CanadaC.L. Vita, R&M Consultants, Inc., Irvine, CaliforniaPlanetary and Remote SensingD.M. Anderson, State University of New York, Buffalo,New YorkR. Arvidson, Washington University, St. Louis,MissouriV. Baker, University of Texas, Austin, TexasD. Birnie, Dartmouth College, Hanover, New HampshireJ. Boyce, NASA, Washington, D.C.M. Darly, Mobil Research & Development, Dallas,TexasK. Dean, University of Alaska, Fairbanks, AlaskaF. Fanale, University of Hawaii, Honolulu, HawaiiE. Gibson, Johnson Space Center, Houston, TexasM. Grolier, U.S. Geological Survey, Flagstaff,ArizonaD. Hall, Goddard Space Flight Center, Greenbelt,MarylandE. Kasischbe, EUIM, Ann Arbor, MichiganP. Kiels, Bureau of Land Management, Anchorage,AlaskaK. Kitcho, Woodward-Clyde Consultants, San Francisco,CaliforniaH, Lang, Jet Propulsion Laboratory, Pasadena,B.CaliforniaLucchitta, U.S. Geological Survey, Flagstaff,ArizonaM.C. Malln, Arizona State University, Tempe, ArizonaP. Mouginis-Mark, University of Hawa i i, Hono luh,D.HawaiiNummedal, Louisiana State Univers ity, BatonRouge, LouisianaP. Patton, Wesleyan University, Mddlerown, Con-A.necticutPeterfraund, Brown University, Providence,Rhode IslandT.L. Pt?w6, Arizona State University, Tempe, ArizonaJ. Pollack, Aws Research Center, Moffett Field,CaliforniaL.A. Rossbacker, Whittier College, Whittier, CaliforniaS. Saunders, Jet Propulsion Laboratory, Pasadena,CaliforniaT, Schmugge, Goddard Space Flight Center, Greenbelt,MarylandJ. Underwood, Kansas State University, Manhattan,KansasG.E. Weller, Geophysical Institute, University ofAlaska, Fairbanks, AlaskaPeriglacial and PermafrostD.M. Barnett, Indian and Northern Affairs, Ottawa,CanadaR.F. Black, University of Connecticut, $torrs,N.ConnecticutCaine, University of Colorado, Boulder, ColoradoD.L. Carter, U.S. Geological Survey, Anchorage,AlaskaE.J. Chamberlain, CRREL, Hanover, New HampshireM.G. Clark, University of Tennessee, Knoxville,A.TennesseeDyke, Geological Survey of Canada, Ottawa, CanadaK.R. Everett, The Ohio State University, Columbus,OhioE. Fahey, University of Guelph, Guelph, CanadaO.J. Perrians, Jr., U.S. Geological Survey, MenloPark, CaliforniaD.C. Ford, McMaster University, Hamilton, CanadaW. Gabriel, Bureau of Land Management, Anchorage,L.AlaskaGoodrich, National Research Council of Canada,Ottawa, CanadaT. D. Hamilton, U, S. Geological Survey, Anchor age,AlaskaS.A. Harris, University of Calgary, Calgary, Cana-D.G.daHarry, University of Western Ontario, London,CanadaJ.A. Heginbottom, Geological Survey of Canada, Ottawa, CanadaD.A. Hodgson, Geological Survey of Canada, Ottawa,CanadaJ. Hunter, Geological Survey of Canada, Ottawa,A.D.CanadaHyers, University of North Carolina, Wilmington,North CarolinaP.G. Johnson, University of Ottawa, Ottawa, CanadaR.H. King, University of Western Ontario, CanadaR.M. Koerner, Polar Continental Shelf Project, Ottawa,CanadaB. Ladanyi, Ecole Polytechnique, Pbntreal, CanadaD.E. Lawson, CRREL, Hanover, New HampshireA.G. Lewkowicz, University of Toronto, Mississauga,CanadaB. Luckman, University of Western Ontario, London,CanadaV.S. Lunardini, CRREL, Hanover, New Hampshire

383F. Michel, Carleton University, Ottawa, CanadaG. Miller, University of Colorado, Boulder, ColoradoF. Nelson, University of Michigan, Ann Arbor,MichiganW. Nickling, University of Guelph, Guelph, CanadaS.I. Outcalt, University of Michigan, Ann Arbor,MichiganT.L. Pb€, Arizona State University, Tempe, Ari-W.H.zonaPollard, University of Ottawa, CanadaL. Price, Portland State University, Portland, OregonV.N. Rampton, Terrain Analysis & Mapping ServicesLimited, Carp, CanadaS. Rawlinson, ADGGS, Fairbanks, AlaskaR.D. Reger, ADGGS, Fairbanks, AlaskaD. Sharpe, Geological Survey of Canada, Ottawa,CanadaC. Tarnocai, Land Resource Research Institute, Ottawa,Cana$aC.E. Thorn,, ,Kiniversity of Illinois, Urbana, Illinois' 'F. Ugolini, University of Washington, Seattle,WashingtonJ.S. Vincent, Geological Survey of Canada, Ottawa,CanadaJ.D. Vitek, Oklahoma State University, Stillwater,OklahomaA.L. Washburn, University of washington, SeaKtle,WashingtonS. Watts, Geological Survey of Canada, Ottawa,CanadaW.J. Wayne, UniversiKy of Nebraska, Lincoln, NebraskaS. White, The Ohio State University, Columbus,OhioS. Zoltai, Environment Canada, Edmonton, CanadaHydrologyI. Barnes, U.S. Geological Survey, Menlo Park,CaliforniaS. Bredthauer, R&M Consultants, Anchorage, AlaskaK.L. Carey, CRREL, Hanover, New HampshireR.F. Carlson, University of Alaska, Fairbanks,AlaskaE.F. Chacho, CRREL, Fairbanks, AlaskaT.B. Coplen, U.S. Geological Survey, &$ton, VirginiaJ. Downey, W.S. Geological Survey, Fairbanks,AlaskaB.T. Drage, Nottingham, Peratrovich and Drage,Anchorage, AlaskaP. Emery, U. S. Geological Survey, Anchorage, AlaskaR.P. Emmanuel, U.S. Geological Survey, Anchorage,AlaskaG.L. Guymon, University of California, Irvine,S.CaliforniaJones, U.S. Geological Survey, Anchorage, AlaskaJ. Knot t, U. S. Geological Survey, Anchorage, AlaskaR. Lamke, U. S. Geological Survey, Anchorage, AlaskaU.E. Lawson, CRREL, Hanover, New HampshireF.A. Michel, Carleton University, OKtawa, CanadaB. Parks, U.S. Geological Survey, Fairbanks, AlaskaC.W. Slaughter, Institute of Northern Forestry,Fairbanks, AlaskaJ. Stein, University of Alaska, Fairbanks, AlaskaC.E. Sloan, U.S. Geological Survey, Anchorage,AlaskaD. Trabant, U. S. Geological Survey, Fairbanks,AlaskaJ.R. Williams, U.S. Geological Survey, Menlo Park,CaliforniaM.K. Woo, McMaster University, Hamilton, CanadaC. Zenone, U.S. Geological Survey, Anchorage,AlaskaEnvironraentalD. Billings, Duke University, Durham, NorthCarolinaL.C. Bliss, University of Washington, Seattle,WashingtonF.S. Chapin, University of Alaska, Fairbanks,AlaskaR. Densmore, University of Alaska, Fairbanks,AlaskaJ.V. Drew, University of Alaska, Fairbanks, AlaskaC.T. Dyrness, Institute of Northern Forestry,Fairbanks, AlaskaB.O. van Everdingen, Environment Canada, Calgary,CanadaK.R. Everett, The Ohio State University, Columbus,OhioW. Gabriel, Bureau of Land Management, Anchorage,AlaskaL.W. Gatto, CRREL, Hanover, New HampshireG. Guymon, University of California, Irvine, CaliforniaL.R. Hettinger, Dames and Moore, Golden, ColoradoM.L. Hienselman, St. Paul, MinnesotaA.W. Johnson, San Diego State University, San Diego,CaliforniaL.A. Johnson, CRREL, Fairbanks, AlaskaP.L. Johnson, Lamar University, Beaumont, TexasG, Juday, Institute of Northern Forestry, Fairbanks,AlaskaG.P. Kershaw, University of Alberta, Edmonton,CanadaA.E. Linkins, Virginia Polytechnic Institute,Blacksburg, VirginiaD.K. MacKay, NaKional Hydrology Research Institute,Ottawa, CanadaJ. Major, University of California, Davis, CaliforniaJ.V. Matthews, Geological Survey of Canada, Ottawa,CanadaJ.D. McKendrick, Agricultural Research Center,Palmer, AlaskaW. MiKchell, Agricultural Research Center, Palmer,AlaskaD.M. Murray, University of Alaska, Fairbanks,AlaskaS.I. Outcalt, University of Michigan, Ann Arbor,MichiganW.A. Patterson 111, University of Massachusetts,Amherst, MassachusettsC. Racine, Johnson State College, Johnson, VermontW.R. Rouse, McMaster University, Hamilton, CanadaG.R. Shaver, Marine Biological Laboratory, WoodsHole, MassachusettsC.W. Slaughter, Institute of Northern Forestry,B.Fairbanks, AlaskaSveinbjornsson, University of Alaska, Anchorage,Alaska

384J. Svoboda, University of Toronto, Mississauga,L.L.CanadaTieszen, Augustana College, Sioux Falls,South DakotaK. Van Cleve, University of Alaska, Fairbanks,AlaskaD.A. Walker, University of Colorado, Boulder,ColoradoP.J. Webber, University of Colorado, Boulder, ColoradoR. Wein, University of New drunswick, Fredericton,CanadaG. Weller, Universlty of Alaska, Fairbanks, AlaskaB. Willard, Boulder, ColoradoM. Wilson, University of Calgary, Calgary, CanadaM.K. Woo, McMaster University, Hamilton, CanadaJ. Yarie, University of Alaaka, Fairbanks, AlaskaS. Young, Center for Northern Studies, Wolcott,VermontJ. Zasada, Institute of Northern Forestry, Fairbanks,Alaska

Appendix D: ParticipationApproximately 900 individuals from 25 countries participated in the conference. Statistics onparticipation are provided in Tables 1 and 2. Names and addresses of all participanrs are given inthis Appendix with an indication of field trips in which each participated.Table 1.Registration and National Representation.Registration Participation by CountryFull 627spouses 80Students 72Daily - 72Total 851(does not include press,dignitaries and supportstaffs)United States 595No may 3Canada Netherlands 3122People's Republic of China 20 Belgium 3Federal Republic of Gemany 18 France 2United Kingdom 16 Czechoslovakia 1Switzerland 8 Argentina 1USSR 6 Chile 1Finland 5 Poland 1Japan 5 Iceland 1Sweden 5 Australia 1Denmark 5 Austria 1Italy 4 South Africa 1Table 2.North American Participation.Federal AgenciesAlaska Non-Alaska Canada ToralU.S. DepartmentsInteriorBLMUSCS"SNPSBIA, FWS, otherAgricultureForest ServicescsTransportationFWAAlaska RailroadDefenseCRRELOther ArmyAir ForceEnergy (incl. National labs)O€fice of Federal InspectorNASANSFU.S. Total2272224722541030- 06309001001016315221I4110 4Canadian Federal Agencies23 23385

386Table 2 (cont'd).North American Participation.Alaska Non-Alaska Canada TotalState, Local and Provincial GovernrentsState of AlaskaTransportation 43Environmental Conservation 5Natural Resources - DGGS 7ocs 1State Governwnt 6Local Government 5Canadian Provincial GovernmentUniversities2672United StatesCanadaStudents51 6221 2237151133758Private and OthersConsulting and Industry 116 76 25 217Spouses 22 35 12 69Others 8 11 a 27

RegistrantsRohn D. AbbotShannon & Wilson, Inc.P.O. Box 843Fa1 rbanks, AK 99707Jaime Aguirre-Puente (A-2)17 Avenue d'Alembert92160 AntonyFRANCEHarriet 0. AllenDept. of GeographyDowni ng P1 aceCambridge, CB2 3ENENGLANDDel A1 1 i son100 Dunbar AveFairbanks, AK 99701Carl Baek-Madsen (A-1, B-6)Danish Geotechnical Inst.1 Mag1 ebiergvei , DK-2880LYWbYDENMARKDhari Bahi atConoco2661 B1 uestemPonca City , OK 74601Kristina AhlnaesGeophysical InstituteUniversity of AlaskaFairbanks, AK 99701Satoshi Akagawa (B-6)4-17 Etchujima, 3-ChomeKOtO-KU. Tokyo 135JAPANJonas Akerman (8-3)Dept.of Physical GeographySolvevgatan 13 S-223 62Lund,SWEDENTom A1 bertNorth Slope BoroughBox 69Barrow, AK 99723James W. A1 drichHydro-ConP.O. Box 60007Fairbanks, AK 99707Vera AlexanderInstitute of Marine ScienceUniversity of AlaskaFairbanks, AK 99701Muhamnad Amzad AliGul f Oi1 Corporati onP.O. Box 3650611000 S. Wilcrest Dr.Houston, TX 77236Bernard 0. AlkireCi vi 1 Engi neeri ng Dept.Mi chi gan Tech. Uni V .Houghton, MI 49931Amos J . and CatherineP.O. Box 304Juneau, AK 99802Jalmar V. A1 toAlyeska Pipeline Service1835 S. Bragaw StreetAnchorage, AK 99512A1 terOrlando B. Andersland (A-1)Dept. of Civil EngineeringMi chi gan State UniversityEast Lansing, MI 48824Co.Duwayne M. and June AndersonFNSM Dean's OfficeState Uni versi ty of NY/BuffaloBuffalo, NY 14260Martha AndrewsInst. of Arctic AlpineUniversity of ColoradoCampus Box 450Boulder, CO 80309Steven A. ArconeCRREL72 Lyme RoadHanover, NH 03755William AshtonBox 81372College, AK 99708Andrew AssurCRREL72 Lyme RoadHanover, NH 03755O.J. AstaritaAlaska Int'l. ConstructionP.O. Box 1410Fairbanks, AK 99707ResearchPalmer Bailey (A-2)25 3rd Infantry RoadFt. Leavenworth, KS 66027Grant C. BakerP.O. Box 82448Fairbanks, AK 99708Thomas Baker (8-4)Geophysical InstituteUni versi ty of A1 askaFairbanks, AK 99701Richard and Carolyn BaldwtnARC0 Oiland Gas Co.8881 Pioneer DriveAnchorage, AK 99504James T. Bales (A-1, 8-41Sergent, Hauskins 6 Beckwith8643 E. Buena TerraScottsdale, AZ 85253S. BanerjeeUni verst ty of Washington132 E. Moore Hall FX-10Seattle, WA 98195Mary BannisterQuadra Engineering401 E. Fireweed Ln.Anchorage, AK 99503Martin Barnett (A-1)Dept. of Indian & NorthernAf fai rsOttawa K1A OH4CANADAWilliam Barr (A-2, 8-31Dept. of GeographyUniversity of SaskatchewanSaskatoon, Saskatchewan S7N OW0CANADA387

388Jay BartonThe Barton GroupP.O. Box 36360Tucson, AZ 85740John BendzQuadra Engineering401 E. Fi reweed Ave.Anchorage, AK 99503Pa ltrick B1 ackCornel 1 UniversityBox 58Bradfield HallIthaca, NY 14853Conrad BaumgartnerDept. Renewable ResourcesGov't of YukonBox 2703Whitehorse, Yukon TerritoryCANADAPeter Bayliss (A-1, 8-4)Geology & Geophysics Dept.University of CalgaryCalgary, Alberta T2N 1N4CANADAAnthony BeatyRoyal Mi 1 i tary Col 1 egeKingston, OntarioKFM555CANADAGerard Beaudoi nAMOCO Production Co.AMOCO B1 dg.Denver, CO 80202Robert C. Beck (A-1)Bechtel Civil and Mineral Inc.P.O. Box 3965 'San Francisco, CA 94119Anne-Christina Bedegrew (8-4)4850 156th Avenue, N.E.Apartment 20Redmond, WA 98052Bjorn Bederson (8-41Fyl keshuset6400 MoldeNORWAYEarl H. BeistlineMi ni ng Consul tmtP.O. Box 80148Fairbanks, AK 99708J. R. BellCivil Engr. Dept.Oregon State UniversityCorvallis, OR 97331John W. Bell (8-4)Nevada Bureau of Mi nes-Geol ogyUniversity of NevadaReno, NV 89557William G. BenjeyMinerals Management ServiceP.O. Box 101159Anchorage, AK 99510Lawrence BennettUniversity of A1 askaDept. of Engi neeri ng Managemen133 Duckeri ngFairbanks, AK 99701Carl S. BensonGeophysical InstituteUniversity of A1 askaFairbanks, AK 99701Richard L. BergCRREL72 Lyme RoadHanover, NH 03755Michael B. and Sidsel Bergmann1221 Shore DriveAnchorage, AK 99515John BestARC0 A1 askaP.O. Box 360Anchorage, AK 99510C. BirchAlaska Dept. of Transportationand Pub1 ic Faci 1 i ti es2301 Peger RoadFairbanks, AK 99701Char1 es Bi sbeeBechtel PetroleumP.O. Box 3456San Francisco, CA 94119Roy and Pauline BjornsonPetro-Canada4008 - 5th Ave., S.W.Calgary, Alberta T3C OC1CANADACharles H. BlackSystems Ecology Research GroupSan Diego State UniversitySan Diego, CA 92182Robert F. Black65 Sawmill Brook Lane, Rt. 3Willimantic, CN 06226R. David BlackOtt Water Eng., Inc.4790 Business Park Blvd.Bldg. D, Suite 1Anchorage, AK 99503t William BlackOffice of Federal Inspector32 Miner's TrailIrvine, CA 92714Steve M. Blasco (, A-2, 8-6)Geological Survey CanadaBedford InstituteDartmouth, Nova Scotia B2Y 4ASCANADADavid L. and Rosie BoggsDP Engi neeri ng6010 Acheson LaneAnchorage, AK 99504Charles W. BolenP.O. Box 1178Flagstaff, AZ 86002James F. BoltzNorth Pole RefiningP.O. Box 56399North Pole, AK 99705Thomas BondStandard 011 Co.4440 Warrensville Ctr. Rd.Cleveland, OH 44128Richard Bonwel 1Fairbanks North Star BoroughP.O. Box 1267Fairbanks, AK 99707Earl J. BooneBureau of Land Management701 C StreetAnchorage, AK 99513Jon C. BoothroydDept. of GeologyUniversity of Rhode IslandKingston, RI 02881

389Bryan E. BorjessonConsul ti ng Engi neeri ngS.R. 40455Fairbanks, AK 99701Kathy BrewerUniversity of AlaskaBox 82282Fa1 rbanks, AK 99708John BugbeePeratrovich & Nottingham Inc.P.O. Box 6105Anchorage, AK 99502William J. BothaHardy Associates Ltd.211 - 18th St SECalgary, Alberta T2E 655CANADARichard BoutsBureau of Land Management701 C StreetAnchorage, AK 99513Peter BowersBureau of Land Management701 C StreetAnchorage, AK 99513Sue Ann BowlingGeophysical InstituteUniversity of A1 askaFairbanks, AK 99701Max C. BrewerU.S. Geologlcal Survey4200 Providence DriveAnchorage, AK 99504Julie K. Brigham (8-4)Inst. of Arctic Alpine ResearchBox 450University of ColoradoBoulder, CO 80309Charles W. and Bernice BritriusTwin City Testing19350 Park Ave.Deephaven, NM 55391Michael I. BrockAlyeska Pi pel i ne Service Co.1835 S. Bragaw StreetAnchorage, AK 99504Bruce E. Brockett (A-2, 8-21CRRELGregg Brad1 ey 72 Lyme Rd.Alaska Dept. of Transportation Hanovet", NH 03755and Public FacilitiesPouch 6900Anchorage, AK 99502 Dixie Brown (8-4)University of A1 aska Foundation590 Uni versi Cy AvenueHerbert K. Brasseur Fairbanks, AK 99701Bureau of Land ManaaementI701 C StreetAnchorage, AK 99513Margaret BurgessEarth Physics Branch1 Observatory Cres.Ottawa, K1A OY3CANADAOskar and Ursee Burghardt (A-2, 8-41Nordrhein-WestfalenDe-Greiffstr 1950-4150 Krefel dWEST GERMANYChristopher BurnDept, of GeologyCarl eton UniversityOttawa K1S 4B6CANADAJames S. BuskaCRRELBull ding 4070Ft. Wainwright, AK 99703Charles But1 erInt'l Engineering Co.,6740 Lunar DriveAnchorage, AK 99504Jerry, Cel ia and Mike Brown (A-2, 6-21 CANbl-CRREL72 Lyme Rd.0. Brauer Hanover, NH 03755 Ne1 CaineA1 aska of Transportation DeptInst. Arctic Research Alpineand Pub1 1 c Faci 1 i ti e$ Box 450P.O. Box 60107 Leslie G. Browne (A-1) University of ColoradoFairbanks, AK 99701 Morrison-Forester Boulder, CO 803091 Market PlazaSan Francisco, CA 94111Phillip F. Brease James E. CaldwellBureau of Land Management EXXON Production Co. ResearchP.O. Box 1150 Michael P. Bruen Box 2189Fairbanks, AK 99707 Harza-Ebasco J.V. Houston. TX 770018740 Hartrell RoadAnchorage, AK 99507Bjorn Bredesen Kerry J. CampbellIngenior F. Selmer McCl el 1 and news EngiBox 6035 Rudolph Buchholz 5450 Ralston St.Oslo 6 Ring 6 StreetVentura, CA 93003NORWAY 0-7770 MarkdorfWEST GERMANYAxel R. CarlsonLloyd R. Breslau SR Box 30173CRREL Fairbanks, AK 9970172 Lyme Rd.Hanover, NH 03755Inc.Edward D. Butterwi ckFoothi 11 s Pipe Lines1600 - 205 5th Avenue, SWCalqarv. Alberta T2P 2V7

390Lome E. Carl sonFoothi 11 s Pipe Li nes1600 - 205 5th Avenue SWCalgary, A1 berta T2P 2V7CANADARobert Carl sonInstitute of Water ResourcesUni versi ty of A1 askaFairbanks, AK 99701Michael H. Carr (A-1)U.S. Geological Survey345 Middl ef i el d RoadMenlo Park, CA 94025David L. and Bettie CarterU.S. Geological Survey4200 University DriveAnchorage, AK 99508L. R. CaseAlaska Int'l ConstructionP.O. Box 1410Fairbanks, AK 99707Daniel A. CaseyA1 aska Dept. of Transportationand Publ ic Faci 11 tiesPouch 2Juneau, AK 99811Edward F, ChachoCRRELBui 1 di ng 4070Ft. Wainwright, AK 99703Edwi n Chamber1 ai nCRREL72 Lyme RoadHanover, NH 03755Charles A. and Lynell ChampionNorthern Technical Service750 W. 2nd Ave., Suite 100Anchorage, AK 99501Earl ChandlerUS Army Corps of EngineersPouch 898Anchorage, AK 99506Chen Guojing (A-1, 8-21Road Research DivisionMi ni stry of Communi cati onsBeijingPEOPLE'S REPUBLIC OF CHlNAChen Xiaobai (A-1, B-6)Lanzhou Institute of Glaciologyand Cryopedol ogyAcademi a Sj nicaLanzhouPEOPLE'S REPUBLIC OF CHINACheng Guodong (A-2, B-4)Lanrhou Institute of Glaciologyand CryopedologyAcademia Si nicaLanzhouPEOPLE'S REPUBLIC OF CHINAEdward J. Chri stensenSohio Petroleum Co.100 Pine St. M/S 111San Francisco, CA 94111Leif Chri stensen (B-6)Geol ogi sk Inst.Aarhus University8000 Aarhus CDENMARKJ. M. ClarkAlyeska Pipeline Service1835 S. Bragaw St.Anchorage, AK 99512Mark H. ClarkSoil Conservation ServlceP.O. Box FPalmer, AK 99645Co.Michael G. Clark (A-21Dept. of Geological ScienceUniversity of TennesseeKnoxville, TN 37996Edwin S. Clarke (8-3)Clarke EngineeringP.O. Box 60007Fairbanks, AK 99706Stanton L. ClarkeWoodward Clyde ConsultantsSRA Box 1160 BAnchorage, AK 99502Gary and Lisa Clay (A-1, 8-41SR 2, Box 219Cave Creek, AZ 85331Stephen M. CliffordDept. of Physics & AstronomyUni versl ty of MassachusettsAmherst, MA 01003John CobbGulf Canada ResourcesP.O. Box 310Calgary, Alberta T2P 2H7CANADANicholas CoetzeeEngineering Dept.University of AlaskaFairbanks, AK 99701Timothy S. Col l ettGeology-Geophysics Dept.University of A1 askaFairbanks, AK 99701Charles M. Coll insCRRELBui 1 di ng 4070Ft. Wainwright, AK 99703Jim Col 1 insMarathon OilCo.P.O. Box 3128Houston, TX 77253John Col 1 insA1 aska Dept. of EnvironmentalConservation437 E StreetAnchorage, AK 99501Rod Combel 1 i ckP.O. Box 82422Fairbanks, AK 99708Bi 1 ly ConnorAlaska Dept. of Transportationand Publ i c Faci 1 i ti es2301 Peger RoadFairbanks, AK 99701John S. ConoverCentury Engi neeri ng , Inc.500 L Street, Suite 200Anchorage, AK 99501Kelly S. CopleyCameron Iron WorksP.O. Box 1212Houston, TX 77251M. Yavuz Corapcioglu (A-1)Dept. of Civil EngineeringUniversity of Del awareNewark, DE 11971

391Samuel W. Corbi n1428 N. Lincoln StreetSpokane, WA 99201Arturo E. Corte (A-2, 8-4)Iani gl a5500 MendozaCasilla De Correo 330ARGENTINADonald M. Coulter (A-2)Dept. of Mechanical EngineeringRoyal Mi 1 i tary Col 1 egeKingston, OntarioCANADAD. CoweeAlaska Dept. of Transportationand Pub1 ic Faci 1 i ti esP.O. Box 60107Fairbanks, AK 99701Robert CrackwellBureau of Land Management701 C StreetAnchorage, AK 99513Charles and Bettie CraddockHarza Engineering Co.201 E. 16th Ave., Apt. 303Anchorage, AK 99501John CraigCRRELBldg 4070Ft. Wainwright, AK 99703Colin Crampton (A-2, 8-61Dept.of GeologySimon Fraser UniversityBurnaby, B.C. V5A 1S6CANADAJohn E. CroninShannon tl Wilson, Inc.P.O. Box 843Fairbanks, AK 99707Kevin M. CroninAMOCO Production Co.1670 BroadwayDenver, CO 80202Cui Chenghen (A-1, B-2)Third Survey and Design Inst.Ministry of RailwaysTianjingPEOPLE'S REPUBLIC OF CHINACui Zhijiu (A-2, 8-41Dept. of GeographyPeking Uni versi CyBei ji ngPEOPLE'S REPUBLIC OF CHI~ADonald CurrieMobile Augers Research. Ltd.5736 103 A StreetEdmonton, Alberta T6H 255CANADAScott Dall imoreGeography Dept.Carl eton UniversityOttawaCANADADouglas H. DasherA1 aska Dept. of EnvironmentalConservationP.O. Box 1601Fairbanks, AK 99701Arlene M. Davi sR. A. Kreig & ASSOC., Inc.1503 West 33rd AvenueAnchorage, AK 99503Louis DeGoes (A-2)Consultant4727 38th Street NArl i ngton, VA 22207Ken DeanGeophysical InstituteUniversity of A1 askaFa1 rbanks, AK 99701Thomas DeanBureau of Land ManagementP.O. Box 1150Fairbanks, AK 99707Larry L. DearbornA1 aska Di vi sion of Geologicaland Geophysical SurveysP.O. Box 77216Anchorage, AK 99501Sue DeglerSohio Alaska PetroleumPouch 6-612Anchorage, AK 99502Allan J. DelaneyCRREL72 Lyme RoadHanover, NH 03755Co.James Deni ngerBureau of Land Management701 C StreetAnchorage, AK 99513Ding Jinghang (A-1, 8-21Northwest Research InstituteMini stry of Rai 1 waysLanzhouPEOPLE'S REPUBLIC OF CHINAJean-Claude Dionne (8-31Dept. of GeographyUniversi t6 Lava1Quebec, GLK 7P4CANADALeroy 0. DiPasqualeA1 aska Area Nati ve Health ServiceP.O. BOX 7-741Anchorage, AK 99510Len DomaschukCi vi 1 Engi neeri ng DeptUniversity of ManitobaWinnipeg, Manitoba R3T 2N2CANADAIngrid DonnerstagQuadra Engineering401 E. Fireweed LaneAnchorage, AK 99503Brent DragePeratrovich 6 Nottingham Inc.1506 W. 36th Ave.Anchorage, AK 99503Francesco Dramis (8-3)Universi ta Di Cameri noViale Beeti 1Cameri no 62032ITALYJ. P. DUPlesSiS (A-1, 6-61Dept * of Appl ied MathUniversity of Stel lenbosch7600 StellenboschREPUBLIC OF SOUTH AFRICAPatrick DuffyFederal Envi ron * Assessment OfficeFontai ne Bui 1 dingOttawa, Ontario K1A ON3CANADAAlan DufourCarl eton Unf versi tyOttawa, K1S 5B6CANADA.

3 92Syl vai n Dufour Earl P. Ellis26-7200 Huntercrest Rd. NW Office of Federal InspectorCalgary, A1 berta T2K 5S4 690 W Lake Ridge Dr.CANADA Eagle River, AK 99577John E. and Lorraine FerrellAlyeska Pipeline Service Co.1835 S. Bragaw StreetAnchorage, AK 99512R. DunningSOH10Pouch 6-612Anchorage, AK 99502John R. EllwoodNOVA, An Alberta CorporationP.O. Box 2535, Station 'M'Calgary, Alberta T2P 2N6CANADAOscar and Muriel FerriansUs S Geol ogi cal Survey345 Mi ddl ef i el d RoadMenlo Park, CA 94025(A-1)Kenneth DuntonInsti tute of Water Resources Morrls J. Engel ke (A-21University of AlaskaBureau of Land ManagementFairbanks, AK 99701701 C. StreetAnchorage, AK 99513Kurt S. DzinichSenate Advisory Counci 1 Warren L. and Mary Ann EnyeartPouch VBox 170 Crestview LaneJuneau, AK 99811 Eagle River, AK 99577Jim Ebersole €sa Eranti (A-2, 8-3)Inst. of Arctic Alpine Research FINN-STROI OYBox 450 Me1 konkatu 18University of Colorado 00210 He1 sinki 21Boulder, CO 80309FINLANDWilliam F. EdigerTrans Canada PI pel i neP.O. Box 54Commerce Court WestToronto, M5L 1CZCANADADavid C. EschAlaska Dept. of Transportationand Pub1 i c Faci 1 i ti es2301 Peger RoadFairbanks, AK 99701K. R. and Lynn EverettChristopher M. and Sharon Effgen Agronomy DepartmentA1 aska Home and Energy Evaluators Ohio State University4101 Arkansas Columbus, OH 43210Anchorage, AK 99503Catherine EganR. W. FadumNorth Carol i na State UniversityInst. of Water Resources 408 Mann HallUniversity of A1 aska Raleigh, NC 27650Fairbanks, AK 99701Kaare Flaate (8-4)Fyl keshuset6400 MoldeNORWAYW. J. FleihmannBechtel Canada Ltd.4 Forest Lane Way #2101Wlllowdale, Ontario M2N 5x8CANADALouis A. FletcherSoi 1 Conservation Service2221 E. Northern Lts. Blvd.Anchorage, AK 99504John P. Flory (8-3)P.O. Box 82462College, AK 99708Wol f gang F1 uegel (8-6)Geographi sches Insti tutUni verstllt HeidelbergLadenburger Str. 806900 HeidelbergWEST GERMANYHoward F1 ugStearns-Roger2075 Tenth St.Boulder, CO 80302Kurt 1. Egelhofer7 Green StreetLebanon, NH 03766Walter FahaP.O. Box 1178Flagstaff, AZ 86002Michael and Katherine Foley (A-11Battelle-Pacific Northwest Lab.Richland, Washington 99352Fraser Fanal eKathleen A. Ehlig (A-2, 8-41 University of Hawaii1560 Via Del Rey 2525 Correa Rd.S. Pasadena, CA 91030 Honolulu, HI 96825Perry G. FrancisBureau of Land Management701 C StreetAnchorage, AK 99513James C. El dri dge Philip Faulkner Jr. & FamilyBureau of Land ManagementStearns-RogerP.O. Box 1150 3416 W. Akron St.Fairbanks, AK 99707 Denver, CO 80231R. T. and Joeann FrankianR. T. Frankian & Assoc.P.O. Box 7762Burbank. CA 91510

393Craig FreasTryck, Nyman & Hayes740 I StreetAnchorage, AK 99501Wi1 1 i am Gabri elBureau of Land Management701 C StreetAnchorage, AK 99513Tom GeorgeGeophysical InstituteUniversity of AlaskaFairbanks, AK 99701Ji 11 A. FredstonAEIDC-Uni versi ty of A1 aska707 A StreetAnchorage, AK 99501Kevf n FreemenRt. 1, Box 407Vashon Island, WA 98070Bruce R. FreitagA1 aska Dept. of Transportationand Publ i c Faci 1 i ti esP.O. BOX 3-1000Juneau, AK 99802MI chel FremondLab. Ctc Des PontsE t Chauss6es58 Bld. Lefebvre75732 Paris, Cedex 15FRANCEHugh French (8-3)Dept. of GeographyUniversity of OttawaOttawa, Ontarlo K1N 6N5CANADARowland FrenchSOH101 Lincoln Center #12005400 LBJ FreewayDallas, TX 75240John FritzAlaska Dept. of Transportationand Publ ic Faci 1 i ti esPouch 6900Anchorage, AK 99502T. C. Fuglestad (A-1)A1 aska Rai 1 roadPouch 7-2111Anchorage, AK 99510Masami FukudaInstitute of Low Temp. ScienceUniversity of Hokkai doSapporoJAPANJohn G. FylesCanadSan Geological Survey601 Booth St.Ottawa, Ontario KIA OE8CANADAW. Lloyd Gallagher4260 Ridge Dri.vePittsburg, CA 94565Francesco Gal 1 avresi7 MoscovaMilanITALYDave Gal 1 owayEXXON Company, U.S.A.Pouch 6601Anchorage, AK 99502John Gal 1 owayU.S. Geological Survey345 Middlefiel d Rd.Menlo Park, CA 94025Martin and Barbara Gamper (A-2. 8-41Geophysical InstituteUniversity Postfach 8033ZurichSWITZERLANDG. V. GanapathyTransport CanadaP.O. Box 8550Winnipeg, ManitobaCANADAR3C OP6Harold Garbei 1School of Mineral IndustryUniversity of A1 askaFairbanks, AK 99701Barbara Gartner11820 Buena Vista DriveLos A1 tos Hills, CA 94022Leonard J. Gaydos (A-2)U.S. Geological SurveyAmes Research Ctr 240-8Moffett Field, CA 94035Bernard J. GayewskiA1 aska Dept. of Envl ronmentalConservation437 E StreetAnchorage, AK 99501Stephen Gerl ekARC0 Alaska InC.P.0 Box 360Anchorage, AK 99510James GilERTEC Northwest Inc.600 W 41st #203Anchorage, AK 99503Harold Gi 11 am104-2nd Ave.Fairbanks, AK 99701Scott C. GladdenRittenhouse-Zemen & Assoc.13837 NE 8th StreetBel levue, WA 98005Roy GlassU. S. Geological Survey1209 Orca StreetAnchorage, AK 99501Kevin J. Gleason (8-3)Unj versi ty of ColoradoDept. of EngineeringBox 424Boulder, CO 80309Robert G1 eckInstitute of Water ResourcesUniversity of A1 askaFairbanks, AK 99701SanJay Godbol ePetroleum Engineering Dept.University of A1 askaFairbanks, AK 99701Douglas J. GoeringBOX a1478Fa1 rbanks, AK 99708David Good100 Bradford StreetOttawa, Ontario K2B 5Y8CANADALaurel Goodrich (8-6)Division of Bui 1 ding ResearchNational Research Council CanadaOttawa, Ontario KlA OR6CANADA

~Joan394Fabio and Roberta GoriFinica Technica DipEnergeti ca Universi taVJa Smarta 3Fi renzeI TAL YGosinkGeophysical InstituteUniversity of A1 askaFairbanks, AK 99701Chris A. GrahamGulf Canada Resources, Inc.401 9th Ave., SWCalgary, Alberta T2P 2H7CANADAE. Carri ngton GregoryQuaternary Research CenterUni versity of WA AK-60Seattle, WA 98195George L. Griffin2866 Marnar DriveSpri ngf i el d, OR 97477Aleksandr I. Gri tsenko (B-6)Al Union Natural Gas ScientificResearch InstituteMinneftegatpromBo1 'shaya Scrpukhovskaya Ulitsa 10Moscow 113093USSRWi1 fried Haeberl iVaw/Agieth ZurichETH-Zentrurn8092 Zuri chSWITZERLANDPaul Haesaerts (8-31IRSNB Rue Vautier 318-1040 Bruxell esBELGIUMHorst Hagedorn (B-3)A1 1 erseeweg 33D8706HochbergWEST GERMANYMike GrahekAlaska Dept. of Transportationand Publ ic Faci 1 i tiesP.O. Box 60107Fairbanks, AK 99701Nikolai Grave (8-2)Permafrost InstituteUSSR Academy of Sciences677010 Yakutsk - 10USSRJames Gray,(B-6)Dept. de GeographieUniversity of MontrealMontreal, Quebec H3C 357CANADAEdwin T. and Maureen C. GreenDept. of Physics/GeologySouthwestern State UniversityWeatherford, OK 73096David F. GreeneGeography Dept.University of CalgaryCalgary, Alberta T2N 1N4CANADALori Greenstein (A-2, 8-31Uni versl ty of Col oradoCampus Box 260Boulder, CO 80309Odd GregersenNorwegian GeotechBox 40 TasenOslo 8NORWAYInstituteGerhard GroeschelBureau of Land Management701 C StreetAnchorage, AK 99513Dora L. GroppRobert W. Retherford Assoc.6728 Diamond Blvd.Anchorage, AK 99502Lucy GroveDept. of GeologyCarl eton UniversityOttawa, Ontario K1S 586CANADAVictor GruolGeophyslcal InstituteUniversity of A1 askaFairbanks. AK 99701George Gryc (8-2)U.S. Geological Survey345 Middl efiel d RoadMenlo Park, CA 94025Robert D. Gunn (8-3)Dept of Chemical EngineeringUniversity of WyomingLarami e, WY 82071Gary L. GuymonCi vi 1 Engi neeri ngUni versi ty of Cal i forniaIrvine, CA 92717Wilbur M. Haas (A-2)Civi 1 Engi neeri ng Dept.Michigan Tech. UniversityHoughton, MI49931Nassrin HajiTu Clausthal Geo Ins.Lei bnizstr 10/0 3392C1 austhal -Zel1 erfWEST GERMANYPeter Hale (8-3)Canada Oil and Gas LandAdministration355 River RoadOttawa, K1A OE4CANADABernard Hal 1 e tQuaternary Research CenterUniversity of WashingtonSeattle. WA 98195John Hal 1 i nFederal Highway Administration708 SW 3rd AvenuePortland, OR 97204Jim J. Hamilton (A-2)Northern Pipeline Agency400-4th Avenue SWCalgary, A1 berta T2P 054CANADARichard A. HamiltonAlaska Department of Transportationand Publ ic Faci 1 i ties8-3-1000Juneau, AK 99811H. HamnerAlaska Dept. of Transportationand Public Facilities2301 Peger RoadFairbanks, AK 99701

395Theodore HamnerDames & Moore800 Cordova, Suite 100Anchorage, AK 99501James C. HarleAlyeska Pipeline Service1835 S. Bragaw StreetAnchorage, AK 99512Lo.J. A. Heginbottom (8-3)Geological Survey of Canada601 Booth StreetOttawa K1A OE8CANADAMikhai 1 Hammond (B-6)Interpreter200 N Adams, Apt. 611Arlington, VA 22201Vince HanemanDept. of EngineeringUniversity of A1 askaFairbanks, AK 99701Peter Hanl eySOHIO PetroleumPouch 6-612Anchorage, AK 99502Sam A. HannasStearns-Roger4175 W. Chenango Ave.Littleton, CO 80123Susan HansenARCO Oiland Gas Co.3201 C Street, Suite 560Anchorage, AK 99503Paul HansonARCO Oiland Gas Co.3201 C Street, Suite 560Anchorage, AK 99503Warren W. HansonDept. of Civil EngineeringUni versi ty of A1 askaFairbanks, AK 99701Wayne C. HansonDames Moore800 Cordova, Suite 100Anchorage, AK 99501William R. HansonElmendorf Air Force Base2704 Orca PlaceAnchorage, AK 99501Peter HardcastleP.O. BOX 81308College, AK 99708Michael HareCarl eton UniversityGeography Dept.Ottawa, KlS 586CANADACharles Harris (8-3)Dept. of GeographyUni versi ty Col 1 egeP.O. 78 Cardiff CF1 1x1UNITED KINGDOMStuart A. Harris (8-31University of Cal gary6316 Dalton DriveCalgary, A1 berta T3A 1E4CANADAWi11 HarrisonGeophysical InstituteUniversity of A1 askaFairbanks, AK 99701David G. Harry (8-3)Dept-of GeographyUniversity of Western OntarioLondon, Ontario N6A 5C2CANADAJudith HarttHartt Enterprises1561/2 Second AvenueFairbanks, AK 99701Richard K. HaugenCRREL72 Lyme RoadHanover, NH 03755John HayesMobile Augers Research Ltd.5736 103 A StreetEdmonton, A1 berta T6H 255CANADADonald W. HayleyEBA Engineering Consul t. Ltd.14535 118th AvenueEdmonton, Alberta T5L 2M7CANADABeez HazenNorthwest A1 aska Pipe1 i ne333 Mi chal senIrvine, CA 92717David and Shirley HeatwoleAnaconda Mi neral s Co *2550 Denali Street, Suite 1000Anchorage, AK 99503Tommy and M. J . He5 nrichAlaska Dept. of Transportationand Publ i c Faci 1 i ti esPouch 6900Anchorage, AK 99502Dot HelmUniversity of A1 askaP.O. Box 3136Fairbanks, AK 99707Kenneth T. HemenwayAlaska Dept. of Transportationand Publ ic Faci 1 i tiesPouch 6900Anchorage, AK 99502James E. HemmingDames & Moore800 Cordova, Suite 100Anchorage, AK 99501Ray E. Herman (A-2)Bureau of Indian Affal rsP.0. BOX 3-8000Juneau, AK 99802Ni 1 s Hetl andSF/Braun505 S. MainOrange, CA 92668Loren R.Hettinger (A-1)Dames & Moore1626 Cole BlvdGo1 den, CO 80401Christopher E. Heuer (8-6)EXXON Production ResearchP.O. Box 2189Houston, TX 77001I. Heyse (A-1, 8-31Geophysical InstituteUniversity of GhentKri jgslaan 281488-900 GhentBELGIUMDuncan Hickmutt (B-6)AI aska Di vi si on of Geol ogi caland Geophysical Surveys794 University Avenue, BasementFairbanks, AK 99701

396David HickokAEIDCUniversity of A1 aska707 A StreetAnchorage, AK 99501John T. Holden (A-1)Dept. of Theoretical MechanicsUniversity of Notti nghamNotti nghamENGLANDMark IngrhamAlaska Division of Geologicaland Geophysical SurveysP.O. Box 1721Eagle River, AK 99577El do Hi 1 debrandDept of Civil EngineeringUniversity of WaterlooWaterloo, Ontario N2L 361CANADADonald W. HollandAlaska Dept. of Transportationand Pub1 i c Faci 1 i tiesPouch 6900Anchorage, AK 99502Ron InnesMobile Augers Research Ltd.5736 103 A StreetEdmonton, Alberta T6H 255CANADAJerry W. HilgertU.S. Forest ServiceInstitute of Northern ForestryUniversjty of AlaskaFairbanks, AK 99701Jim HillierQuadra Engineering401 E. Fireweed LaneAnchorage, AK 99503Henry E. Holt (A-2, B-4)P1 anetary Geology , EL-4NASA HeadquartersWashington, D.C. 20546David M. Hopkins (B-6)U .S Geological Survey345 Mi ddl ef i el d RoadMail Stop 90-BMenlo Park, CA 94015Ralph and Barbara IsaacsNorthwest Al aska Pipe1 1 ne3333 Michel son DriveIrvine, CA 92717Edmonton S. JacobsenA1 aska Dept. of EnvironmentalConservation431 E StreetAnchorage, AK 99501George D. and Arlie HobsonPolar Shelf Project880 Wellington Street, Rm 401Ottawa, K1A OE4CANADADavid HochPeratrovich & Notti ngham Inc.1506 W. 36th AvenueAnchorage, AK 99503Grant and Elsie HockingApplied Mechanics, Inc.(B-6)3000 Youngfield Street, #285Lakewood, CO 80215Pieter HoekstraGeo-Physi -Con Inc.12860 W. Cedar Drive, Suite 201Lakewood, CO 80228Philip HoffmanGeophysical InstituteUniversity of A1 askaFairbanks, AK 99701J.E.F. and Jean Ann HogganHoggan Engineering & Testing Ltd8803 50th AvenueEdmonton, Alberta T6E 5H4CANADACharlotte HokInstitute of Water ResourcesUniversity of A1 askaFairbanks, AK 99701Theodore and Laura Hromadka24731 Via A1 voradoMission Viejo, CA 92691Scott HuangSchool of Mineral IndustriesUniversity of AlaskaFaf rbanks, AK 99701Terence and Beverly Hughes (A-2)Dept. of Geological SciencesUniversity of Maine at OronoOrono, ME 04469Jim HunterGeological Survey of Canada601 Booth StreetOttawa, Ontario K1A OE8CANADARonald G. HuntsingerBureau of Land Management701 C StreetAnchorage, AK 99513Timothy HushenPolar Research Board2101 Constitution Ave. NWWashington, D.C. 20545Albert 0. and Peggy Hyers (8-4)Earth Science Dept.University of North CarolinaWi1 mington , NC 28406George JacobsenTower Arctic Ltd., Suite 920,1350 Sherbrooke Street WestMontreal, Quebec H3GlJ1CANADAAlfred Jahn (A-2, B-4)Department of GeographyUniversity of Wrocl awP1. Uniwersytecki 150-137 WroclawPOLANDHans and Suse Jahns (A-1, B-6)EXXON Production Research Co.P.O. Box 2189Houston, TX 77001Ric JanowiczDept. of Indian Affairs200 Range Rd.Whitehorse, Yukon Y1A 3VICANADALars-Eric JansonVBB Consul ti ng GroupBox 5038S-102 41 StockholmSWEDENJohn Jardi neArctic Foundations5 Chester StreetWinnipeg, ManitobaCANADAR2L 1W5

397Peter and Lesley JarrettDept. of Civil EngineeringRoyal Mi 1 i tary Col 1 egeKingston, Ontario K7L 2W3CANADALarry JaycoxAnaconda Mineral s Co.555 17th Street, Rm 2146Denver, CO 80202John 0. JenkinsU.S. Army Corps of EngineersP.O. Box 2870Portland, OR 97208Hans L. JessbergerUniversit of BochumUn i versi t 3i t ss tr . 150463 BochumWEST GERMANYAnn JochensGulf Oi1 Corporati onP.O. Box 111683Anchorage, AK 99511Nils I. JohansenSchool of Mineral IndustriesUniversity of A1 askaFairbanks, AK 99701Glenn E. Johns (A-2)City of JuneauP.O. Box 1393Juneau, AK 99802A1 bert W. JohnsonVice President Academic AffairsSan Diego State UniversitySan Diego, CA 92182Danny JohnsonAlaska Dept of Transportationand Public Facilities2301 Peger RoadFairbanks, AK 99701Elden R. JohnsonAlyeska Pipeline Service1835 S. Bragaw StreetAnchorage, AK 99512Co.Eric JohnsonAlaska Dept. of Transportationand Pub1 ic Fac1 11 tiesPouch 6900Anchorage, AK 99502Larry A. JohnsonCRREL83 A Arctic Health BuildingFairbanks, AK 99701G. H. and Terry Johnston (A-1)Di vi sion of Bui 1 ding ResearchNational Research Councll CanadaOttawa, K1A OR6CANADARonald H. Jones (A-1)Dept. of Civil EngineeringUni versi ty of Notti nghamNottingham NG72RDENGLANDStephen J. JonesN.H.R.I. Inland WaterEnvironment CanadaOttawa, K1A OE7CANADAHeinz-Peter Jons (B-4)Geol. Inst. der T.U.Lei bni zstrasse 103392 C1 austhal -Zel1 erfel dWEST GERMANYDarryl F. JordanARC0 Oiland Gas700 G. St. (P.O. Box 100939)Anchorage, AK 99501Harold Jorgenson2039 New Hampshire Ave. NWWashington, D.C.Noel and C. Journeaux8803 50 AvenueEdmonton. Alberta T6E 5H4CANADAGlenn JudayU.S. Forest ServiceInstitute of Northern ForestryUniversity of A1 askaFairbanks, AK 99701James H. JusticeUni versi ty of Cal garyES 104/2500 University Dr. NWCalgary, Alberta T2N 1N4CANADADoug1 as KaneInstitute of Water ResourcesUniversity of A1 askaFairbanks, AK 99701Eric T. Karlstrom (8-4)Dept. of GeologyNorthern Arizona Uni VerSitYBox 15106Flagstaff, AZ 86011Johannes Karte (B-3)Deutsche ForschungsgemeinschaftKennedyall ee 400-300 Bonn, 2,WEST GERMANYGary Kast3701-19 Street NECalgary, Alberta T23 6S8CANADAKoji and Virginia KawasakiGeophyslcal InstituteUni versi ty of A1 askaFa1 rbanks, AK 99701B. 0. KayDept. of Land ResourcesUniversity of Guel phGuel ph, Ontari 0CANADAGeoffrey and Bron Kellaway (A-1)14 CranedownLewes, Sussex BN7 3NAUNITED KINGDOMRobert KenyonDept. of Civil EngineeringUniversity of ManitobaWinnipeg, Manitoba R3T 2N2CANADAHans Kerschner (6-31Institute fur GeographieUniverstBt InnsbruckA 6020 InnsbruckAUSTRIAG. Peter KershawDept. of GeographyUniversity of A1 bertaEdmonton, Alberta T6G 2H4CANADARoger J. KettleDept, of Civil EngineeringU/Aston Gosta GreenBirmingham 84 7ETENGLAND

398Harry KieftePhysics DepartmentMemorial UniversitySt. John ' s , Newf oundl and AlB3X7CANADADaniel J. KoelrerAlyeska Pipeline Service1835 S. Bragaw StreetAnchorage, AK 99512Co.Thomas G. KrzewinskiDames & Moore800 Cordova, Suite 100Anchorage, AK 99501John and Margaret Kiely (8-3)Bechtel Power Corporati onP.O. Box 3965 (850112)San Francisco, CA 94119Byron E. KoepkeSoi 1 Conservation ServiceP.O. Box FPalmer, AK 99645Matthias KuhleUni versi tit Gatti ngenGo1 dschmi dtstr 5D-3400 Gdtti ngenWEST GERMANYLorenz King (A-2)Geophysical InstituteUniversity of HeidelbergOtto Hahn Platz 2D-6900 HeidelbergWEST GERMANYMichael S. KingEarth Sciences DivisionLawrence Berkeley LaboratoryBerkeley, CA 94720Robert E. KingBureau of Land ManagementP.O. Box 1150Fairbanks, AK 99707Thomas C. KinneyShannon & Wilson, Inc.P.O. Box 843Fairbanks, AK 99707Takeei Koizumi (A-1, B-4)Dept. of GeographyTokyo Gakugei UniversityKoganei City, Tokyo 184JAPANElse Kolstrup (8-3)Jemtel andsgade 8 , 4th2300 Kobenhavn SDENMARKVera KomarkovaInst. Arctic and Alpine ResearchCampus Box 450University of ColoradoBoulder, CO 80309Jean-Marie KonradNational Research CouncilOttawa, KIA OR6CANADAEduard KosterSei 5 ti Ki nosi taPhysical Geogr. LabInstitute LOW Temperature Science University of AmsterdamHokkai do Uni versi tySapporoDapperstraat 1151093-6s AmsterdamJAPANTHE NETHERLANDSBruce H. Kjartanson Nat W. and Mrs. KrahlDepartment of Civil Engineering Brown & Root, In,-.Unlversi ty of ManitobaP.O. BOX 03-635Winnipeg, Manitoba R3T 2N2Houston, TX 77001CANADALen Knapik418 Hillside Park51112 RGE Rd. 222Sherwood, Park, AlbertaCANADALarry KnapmanBureau of Land ManagementP.O. Box 1150Fairbanks, AK 99707Sven KnutssonUniversity of LuleaDivision of Soil MechanicsS-95187 LuleaSWEDENT8C 1G9CanadaWilliam 8. Krantz (8-3)Department Chemical EngineeringUniversity of ColoradoBoulder, CO 80309Raymond A. Kreig (A-2, 8-31R. A. Kreig Assoc.1503 West 33rd AvenueAnchorage, AK 99503Dionyt Kruger (A-2)Foothi 11 s Pipe1 i ne Ltd.1715 110th Ave., SWCalgary, A1 berta T2W OE4CANADAVladimir P. Kuleshov (B-6)Al Union Natural Gas ScientificResearch InstituteMinneftegazpromBo1 'shava Scrpukhovskaya U1 i tsa 10Moscow 113093USSRWilliam F. KuperCrorley A1 1 Terrain Corporation201 Danner Ave., Suite 200Anchorage, AK 99502Mark LaForteApplled Research CenterCRCAC3800 Cremazie St.Montreal, H2B 158CANADALouanne Label 1 eBedford Institute OceanographyBox 1006 DartmouthNova Scotia B2Y 4A2CANADABranko and Neva LadanyiCivi 1 EngineeringEcol e Polytech *CP6079 St. AMontreal. Quebec H3C 3A7CANADAJ.M.C. LalondeDept. of GeographyUniversity of TorontoToronto, Ontario M5S 1AlCANADAHans C. LangagerGreen1 and Technical Organi zati onHauser Plads 20DK 1127 Copenhagen KDENMARKRoger Langohr (8-3)Earth Sci. Inst.University of GhentKri jgsl aan 281B-9000-GhentBELGIUM

399H. Gordon and Mary Jo Larew2500 Hillwood PlaceChar1 ottesvi 11 e , VA 22901Guy Larocque (A-2)Soci et@ d' Energi e800 E De MaisonneuveMontreal, H2L 4M8CANADAWayne F. LarsonNorthern Lati tude Assoc.S. R. Box 10326Fairbanks, AK 99701Steve LautDome Petroleum224 McQueen Glen P1.Calgary, Alberta T2J 4E2CANADACraig Lavi el leRi ttenhouse-Zeman & ASSOC -13837 NE 8th StreetBel levue, WA 98005Daniel E. Lawson (8-41CRREL72 Lyme RoadHanover, NH 03755L.C.M.F Limited723 W. 6th AvenueAnchorage, AK 99501Rai ner LehmannBi smarckstr 22A0-6831 P1 ankstadtWEST GERMANYGi11 es Lemai reGeotechni cal Dept .Ecol e Polytecni queMontreal, Quebec H3C 3A7CANADADebbie LevUniversity of Washington6812 21st NESeattle, WA 981950. LevineAlaska Dept. of Transportationand Publ ic Faci 1 i ties2301 Peger RoadFairbanks, AK 99701Robert Lewell enLewell en Arctic ResearchP.O. Box 2089Palmer, AK 99645Robert F. LewisAlaska Dept. of Transportationand Public FacilitiesPouch 6900Anchorage, AK 99502Antoni G. Lewkowicz (A-1)Dept of GeographyUniversity of TorontoToronto, Ontario M5S 1AlCANADALi Yusheng (A-1, 8-2)Academy of Railway SciencesMinistr-v of RailwaysBei ji ngPEOPLE S REPUBLIC OF CHINARoy A. LidgrenPublic Works Canada201 Ranger RoadWhitehorse, Yukon TerritoryY1A 3A4CANADAHerbert Liedtke (A-1, 8-31Kellermannsweg 104630 BochumWEST GERMANYArthur E. LinkinsBiology Dept.VPI & suBlackburg, VA 24061George Li nkl etterWoodward-Clyde Consultants203 N. Go1 den Circle DriveSanta Ana, CA 92667Liu Hongxu (A-2, 8-41Low Temperature ConstructionScience Research Institute20 Oingbin RoadHarbi nPEOPLE'S REPUBLIC OF CHINAHal Li vi ngston (A-2)Alaska Dept. of Transportationand Publ ic Facll i ties2301 Peger RoadFairbanks, AK 99701Thomas W. and Jan LivingstonLi vi ngston $1 one, Inc.3900 Arctic Blvd.Suite 301Anchorage, AK 99503Kevin J. LomasCivi 1 Engineering Dept.University of Techno1 ogyLoughboroughENGLANDErwin LongArctic Foundation Inc.5621 Arctic Blvd.Anchorage, AK 99502Ed LopezKPFF Consultant Engineers750 W. 2nd Ave., Suite 207Anchorage, AK 99501Kenneth LovelaceAlyeska Pipe1 i ne Service Co.1835 S. Bragaw StreetAnchorage, AK 99512C. William and Janet Love11School of EngineeringPurdue Uni versl tyW. Lafayette, IN 47907Douglas L. LoweryA1 aska Dept. of EnvironmentalConservationPouch 1601Fairbanks, AK 99701Phil LowryDept. of GeologyLoui si ana State UniversityBaton Rouge, LA 70803Lu Guowei (A-1, 6-61Yakeshi Institute of ForestrySurvey and DesignInner MongoliaYakeshiPEOPLE'S REPUBLIC OF CHINABaerbel Lucchitta (A-2, 6-31U.S. Geological Survey2255 N. Gemini DriveFlagstaff, AZ 86001Virgi 1 Lunardi niCRREL72 Lyme RoadHanover, NH 03755

400Davfd P. LuschCenter for Remote SensingMichigan State University302 Berkey HallEast Lansing, MI 48824U1 rich and Joanne LuscherWoodward-Clyde Consultants100 Pri ngle AvenueWalnut Creek, CA 94596H. A. MacAul ayGeological Survey601 Booth StreetOttawa K1A OE8CANADAKaye MacInnes (A-2)Land ResourcesBox 1500Yellowknife, N.W.T.CANADAof CanadaX1A 2R3Stephen F. MackAlaska Division of Geologicaland Geophysical Surveys4420 Airport WayFairbanks, AK 99701J. Ross and Mrs. Mackay (8-3)Dept of GeographyUni versl ty of Bri ti sh ColumbiaVancouver, B.C. V6T 1W5CANADADaniel and Eileen MageauR & M Consultants, Inc.59 Goldrush EstatesFairbanks, AK 99701Larry Mahar3351 Ocana AvenueLong Beach, CA 90808Arshud MahmoodMcClelland-EBA, Inc.4649 Business Park Blvd.Anchorage, AK 99503Joe P. MahoneyUniversity of WashingtonMoore Hall, FX-10Seattle, WA 98195Max Maisch (A-2, 8-41Geophysical InstituteUniversity of ZurichPostfach ICH-8033 ZurfchSWITZERLANDHarri Makela (A-2 8-6)VTT Geo LabSF 02150 Espoo 15FINLANDSeppo MakiViatek Ltd.P.O. Box 02101 Espoo 10FINLANDMSchel C. MalinDept of GeologyArizona State Un+i versi tyTempe, AZ 85287Edward Maltby (A-2)Geography Dept.Exeter UniversityExeter, Devon, 3x4 4RJENGLANDChi-Sing Man (B-6)Dept. of Civil EngineeringUni versi ty of ManitobaWinnipeg, Manitoba R3T 2N2CANADAVictor Mani k i anARC0 A1 aska Inc.3317 WentworthAnchorage, AK 99504Herb MannFairbanks North Star BoroughP.O. Box 1267Fairbanks, AK 99707David MarrettM/S AR-10University of WashingtonSeattle, WA 98195Philip S. MarshallAEIDCUniversity of Alaska707 A StreetAnchorage, AK 99501Mark Marti nsonAlaska Dept. of Transportation'and Publ ic Faci 1 i ti esP.O. Box 60107Fairbanks, AK 99701Nabi c MasriAlaska OCS Reg.District Minerals Office411 W. 4th Ave, Suite 2AAnchorage, AK 99501Amos C. MathewsOffice of the Federal InspectorP.O. Box 6619Anchorage, AK 99502Mark MathewsLos Alamos National Lab1532 42nd StreetLos Alamos, NM 87544Ronald MatviyakMat-Vi ak Engineering1311 4th AvenueFairbanks, AK 99701Lawrence MayoU.S. Geological Survey10112th AvenueBox 11Fairbanks, AK 99707E. Y. McCabeDept. of Civil EngineeringUniversity of Aston, Gosta GreenBjrmingham B4 7ETENGLANDDavid McCal ebAlaska Dept. of Transportationand Publ ic Faci 1 i ti es2301 Peger RoadFairbanks, AK 99701He1 en McCammonDept. of EnergyMS E201Washington, D.C. 20545Joseph McCl oskeySoi 1 Conservation Service2221 E. Northern Lights Blvd.Anchorage, AK 99504Patricia A. McCormick (A-2)SR 30505Fairbanks, AK 99701John McCoyBureau of Land Management701 C StreetAnchorage, AK 99513MJ ke McCrumInstitute of Water ResourcesUniversity of A1 askaFairbanks, AK 99701

401Steven McCutcheonAlaska Pictorial ServiceP.O. Box 6144Anchorage, AK 99502Oonal d C. MearesBureau of Land ManagementP.O. Box 1150Fairbanks, AK 99707Tom and Helen MiklautschMikl autsch & Associates1001 NobleFairbanks, AK 99701Patrick McDevi ttAlyeska Pipe1 i ne Service Co.1835 S. Bragaw StreetAnchorage, AK 99512Brainerd Mears .Jr. (A-2, 8-41Department of GeologyUniversity of WyomingLaramie, WY 82071Mark MilesInstitute of Water ResourcesUniversity of A1 askaFairbanks, AK 99701Jim McDougallESSO Research Canada Ltd.237 Fourth Ave SWCalgary, Alberta T5J 2R5CANADABo McFaddenQuadra Engineering401 E. Fireweed LaneAnchorage, AK 99503Terry McFaddenMechanical EngineeringUniversity of AlaskaFairbanks, AK 99701Richard W. McGawCRREL72 Lyme RoadHanover. NH 03755Pete McGeeAlaska Dept. of EnvironmentalConservationPouch 1601Fairbanks, AK 99701Robert L. McHattieAlaska Oept. of Transportationand Pub1 ic Faci 1 i ti es2301 Peger RoadFairbanks, AK 99701Karen McKennaDept. of Renewable ResourcesGovernment of YukonBox 2703Whitehorse, Yukon TerritoryCANADAHarlan L. McKimCRREL12 Lyme RoadHanover, NH 03755William B. McMullen (8-2)Alaska Dept. of Transportation and FINLANDPublic Facilities600 University Ave., Suite 8Fairbanks, AK 99701Jack MellorBureau of Land ManagementP.O. Box 1150Fairbanks, AK 99707P. I. Melnikov (B-6)USSR Academy of SciencesCouncil on Earth Cryology11 Fersman St.Moscow 117312USSRKaren S. Metz4610 EdinburghAnchorage, AK 99502Michael Metz (A-2, B-3Geo Tech. Service Inc.14379 W. El 1 sworth AveGo1 den, CO 80401W. P. MetzARC0 Alaska, Inc.4610 EdinburghAnchorage, AK 99502Kevin G. MeyerBureau of Land Management701 C StreetAnchorage, AK 99513Paul R. MeyerAE I DCUni versi ty of A1 aska707 A StreetAnchorage, A, 99501Fred Mi chelDept. of GeologyCarleton UniversityOttawa, Ontario K1S 586CANADAMartti Mietti nenViatek OyP1 4 02101 ESDOO 10Bob R. MillerTSA Systems Inc.4919 N. BroadwayBoulder, CO 80302Caroline A. MillerP.O. Box 701Eagle, River, AK 99577Duane L. MillerDuane Miller & AssociatesSRA Box 20458Anchorage, AK 99507John Mi 11 erGeophysical InstituteUniversity of AT askaFairbanks, AK 99701P. MillerAlaska Dept. of Transportationand Public FacilitiesP.O. Box 60107Fairbanks, AK 99701Robert 0. Miller (A-1)Cornel 1 University538 Cayuga Heights RoadIthaca, NY 14850Robert E. MillerCi vi 1 EngineerUniversity of A1 askaAnchorage, AK 99508Wendell P. MillerAlaska Dept. of Transportationand Public Facilities5600 B Street, Suite 202Anchorage, AK 99502A1 exey Mi ndi c h8339 North Chri Sti anaSkokie, IL 60076Pavol Mitter (8-2)Skolska 4 03101Liptovsky MikulasCZECHOSLOVAKIA

40 2Joseph P. MooreSoi 1 Conservation Service2221 E. Northern Lights Blvd.Anchorage, AK 99504Daryl MoorheadEcology ProgramUniversity of TennesseeKnoxville, TN 37916John MorackPhysics DepartmentUniversity of AI askaFairbanks, AK 99701Norbert MorgensternUni versi ty of A1 bertaDept,of Civil EngineeringEdmonton, Alberta T6G 2G7CANADADrew MorrisUnion OilCo.P.O. Box 6247Anchorage, AK 99502Leslie A. MorrisseyTechnicolor Gov't Service Inc.MS 242-2 Ames Research CenterMoffett Field, CA 94035Thomas L. MosesAlaska Dept. of Transportationand Publ ic Faci 1 i tiesPouch 6900Anchorage, AK 99502W. MoyleAlaska Dept. of Transportationand Public Facilities2301 Peger RoadFairbanks, AK 99701George Muel lerInstitute of Water ResourcesUniversity of A1 askaFairbanks, AK 99701Jeffrey L. Mueller (B-6)Conoco, Inc.1000 S. Pine - 111NTPonca City, OK 74603Mark P. MuirQuaternary Research CenterUniversity of Washington AK-60Seattle, WA 98195Ernest and Wanda Muller (A-2)Syracuse University204 Heroy Geology LaboratorySyracuse, NY 13210Bob MunsonDept. of Transportationand Publ ic Faci 1 i ti esP.O. Box 60107Fairbanks, AK 99701Allen W. Murfitt8050 King StreetAnchorage, AK 99502Monica MurphyGeneral Del i veryAlakanuk, AK 99554David and Barbara MurrayMuseumUni versl ty of A1 askaFairbanks, AK 99701Doug1 as H. MurrayUniversity of AlaskaP.O. Box 82282Fairbanks, AK 99708Ivan and Huong MuzikDept. of Civil EngineeringUni versi ty of CalgaryCalgary, Alberta T2N 1N4CANADAJohn E. and Peggy C. MyrickNorthwest Alaskan Pipeline Co.3333 Mi chel son Ori veIrvine, CA 92730S. Nakagawa (8-6)NKK America Inc.444 5. F1 ower St., Suite 2430Los Angeles, CA 90017H. Nakajima (8-6)NKK America Inc.444 5. Flower Street, Suite 2430Los Angeles, CA 90017Lynette NakazawaBureau of Land Management701 C StreetAnchorage, AK 99513Frank P. NaruschAlaska Dept. of Transporationand Publ ic Faci 1 i tiesPouch 6900Anchorage, AK 99502Gerald and Carol NeaveNorthern Seismic AnalysisRR #1Echo Bay, Ontario POS K OCANADABonita Nei 1 andUni versi ty of A1 askaP.O. Box 10095Fairbanks, AK 99701Fri tr Ne1 sonDept. of Geological SciencesUniversity of MichiganAnn Arbor, MI 48109Gerald E. Ne1 sonDepartment of GeologyCasper College125 College DriveCasper, WY 82601Gordon Ne1 sonU - S. Geol ogi cal Survey1515 E. 13th Ave.Anchorage, AK 99501Robert Nesselhauf1606 Marika Road, #2Fairbanks, AK 99701James F. Neuenschwander (8-3)SOH10Midland Building Rm 877HBCleveland, OH 44115Robert J. Neukjrchner (B-6)Geotec Service Inc.14379 W. Ellsworth Ave.Go1 den, CO 80401Thomas C. NeunaberFederal Highway Admi ni strati onP.O. Box 1648Juneau, AK 99802R. W. Newbury994 Dorchester Ave.Winnipeg, Manitoba R3MOS1CANADADavi d Ni chol 1 sSoil Test Inc.2205 Lee StreetEvanston, IL 60202Bernard NidowiczHarding-Lawson Associates601 East 57th PlaceAnchorage, AK 99502

403J. F. NixonHardy Associates (1978) Ltd.221-18th St. SECalgary, A1 berta T2E 6J5CANADADennis J * NormileFranklin & Allen, Inc.1813 E First Ave., Suite 207Anchorage, AK 99501Ni kol as NugentSchool of Mineral IndustriesUniversity of A1 askaFairbanks. AK 99701Dag NumedalDept. of GeologyLouisiana State UniversityBaton Rouge, LA 70803David A. NussU.S. Air ForcePSC #4Elmendorf AFB, AK 99506Joseph L. OliphantCRREL72 Lyme RoadHanover, NH 03755R. OlmsteadAlaska Dept. of Transportationand Public FacilitiesP.O. Box 60107Fairbanks, AK 99701Kim 01 srewskiSoi 1 Conservation ServiceP.O. Box FPalmer, AK 99645James P. OrmsbyNASA1367 Poplar Hil DriveAnnapolis, MD 21401Thomas E. Osterkamp (A-2)Geophysical InstituteUniversity of AlaskaFa1 rbanks, AK 99701Jerrv ParkerSohi;Midland Building, Rm. 877HBCleveland, OH 44115Walter ParkerParker Associates, Inc.3724 Campbell Airstrip Rd.Anchorage, AK 99504Bruce ParksU.S. Geological Survey101 12th Ave., Box 11Fairbanks, AK 99701Tony PascoalRR #4Odessa, Ontario KOH 2H0CANADAAlmo Paukkonen (8-61P.O. Box 2279101 Leppavi rtaFINLANDKenneth NymanArc0 Pipe Line Co.515 S. Flower St.Los Angeles, CA 90071Deane Oberste-Lehn (A-1P.O. Box 4706Stanford, CA 94035Ann OdaszUniversity of ColoradoCampus Box 8-334Boulder, CO 80309William 6. OdomSohio Alaska PetroleumPouch 6-612 TP2-3Anchorage, AK 99507Co.Walter C. OechelEcosystemslBiology Department$an Diego State UniversitySan Diego, CA 92182OK LumberP.O. Box 104494 Mi,01 d Steese HighwayFairbanks, AK 99701RIchard 01 dfordAlaska Dept. of Transportationand Publ ic Faci 1 i tiesPouch 6900Anchorage, AK 99502Pertti Paukku (8-6)Ed OswaldS.A. Tervo OYPacific Forest Research CenterKauppakatu 28506 W. Burnside Road80100 Joensuu 10Victoria. British Columbia V82 1M5 FINLANDCANADAJon Paul sen3581 Blue Lake B1 vdThomas R. Ottl eyB1 ue Lake, CA 95525Alaska Dept. of Transportationand Publ i c Faci 1 i tiesPouch 6900Dan R. PaveyAnchorage, AK 99502Alaska Dept. of TransportationSamuel Outcal tDept. of Geological SciencesUniversity of Mi chi gan1006 C. C. Little Bldg.Ann Arbor, MI 48109Terry Owen (8-6)A1 aska Di vi si on of Geologicaland Geophysical Surveys794 University Avenue, BasementFairbanks, AK 99701A. C. PalmerR. J. Brown & AssociatesRyswi j kHOLLANDAndre Pancta (8-4)Prominade - 12056 DombressonSWITZERLANDand Publ ic Faci 1 iPouch 6900Anchorage, AK 99502Mike PavoneEbasco Service Inc.400-112th Ave NEBellevue, WA 98004tiesEdward PennerDivision of Building ResearchNational Research Councj 1 CanadaOttawa, K1A OR6CANADAEd PerfectCornel 1 University#61 Bradfield HallIthaca, NY 14853Bob PetersCentury Engineering Inc.500 L Street, Sul te 200Anchorage, AK 99501

404John K. PetersenGeophysical InstituteUniversity of A1 askaFairbanks, AK 99701Robert J, Peterson3M Company6121 Coda AvenueEdina, MN 55436Troy and Mary Jean Pewe (A-l,B-4)Dept. of GeologyArizona State UniversityTempe, AZ 85287Walt PhilipsQuadra Engi neeri ng401 E. Fireweed Ave.Anchorage, AK 99503Janet Phillips1420 North NevadaColorado Springs, CO 80907Arvi nd PhukanSchool of Engi neeri ngUniversity of A1 aska3221 ProvidenceAnchorage, AK 99504Jean PilonEarth Physics Branch1 Observatory CresOttawa, K1A OY3CANADAChien Lu PingAgricultural Experiment StationP.O. Box AEPalmer, AK 99645David A. Pi scherDames & Moore155 NE 100th. Suite 100Seattle, WA 98125R. PlatzkeAlaska Dept. of Transportationand Pub1 ic Faci 1 i ties2301 Peger RoadFairbanks, AK 99701Jean Poi tevi n5009 Clanranald, Apt. 37Notre Dame De GraceMontreal, QuebecCANADADeni se Poley2519 - 17th Ave NWCalgary, Alberta T2M OR8CANADAWayne H. Pollard (8-3)Dept. of GeographyUniversity of OttawaOttawa, Ontario KIN 6N5CANADANoel Potter, Jr. (A-2, 8-4)Dept. of GeologyDicki nson Col 1 egeCarl isle, PA 17013Suzanne PrestrudDept. of Geological SciencesUniversity of Washington, AJ-20Seattle, WA 98195Jonathan Price112 Clarence Ave. NorthSaskatoon, SaskatchewanCANADADr. K. Priesnitz (B-6)Dept. of GeologyGo1 dschmi dtstr. 50-3400 Gotti ngenWEST GERMANYS7N lH8Nikola P. Prokopovich (A-1, 8-42800 Cottage WaySacramento, CA 95825Anne C. PufferU.S. Forest ServiceP.O. Box 1628Juneau, AK 99802Nam K. Pui4903 Verulum P1 ace, N StreetCalgary, A1 berta T3A OJ9CANADACharles H. RacineDivision of Environmental StudiesJohnson State Col 1 egeJohnson, VT 05656Stephen RaeP.O. Box 80508Fairbanks, AK 99708Ernest R. RahaimS & S Engineering Inc7125 01 d Seward HighwayAnchorage, AK 99502Eric Ral stersSohio A1 aska PetroleumPouch 6-612Anchorage, AK 99502Vernon and Joyce Rampton (A-2)Terra1 n An/Mp Service LCd.P.O. Box 158Carp, Ontario KOA 1LOCANADAStuart Raw1 i nson (8-6)Alaska Division of Geologicaland Geophysical Surveys794 University Ave., BasementFairbanks, AK 99708Jerome RaychelU.S. Army Corps of EngineersPouch 898Anchorage, AK 99506Richard ReanierCollege of Forestry Research) University of WashingtonSeattle, WA 98195Michael W. ReedAlyeska Pipe1 i ne Service Co.1835 S. Bragaw StreetAnchorage, AK 99512Richard 0. Reger (8-4)Alaska Division of Geologicaland Geophysical Surveys794 University Ave., BasementFairbanks, AK 99701Ovid A. PlumbCol lege of Engi neeri ngWashington State UniversityPullman, WA 99164Qiu Guoqing (B-4)Lanzhou Institute of Glaciologyand Cryopedol ogyAcademia SinicaLanrhouPEOPLE'S REPUBLIC OF CHINARobert L. ReidMechanical and Industri a1Engineering Dept.University of Texas at El PasoEl Paso, TX 79968

40 5Richard G. ReiderDept. of GeologyUniversity of WyomingLaramie, WY 82071Stephen ReimerUniversity of California, Berkeley3001 Ful tonBerkeley, CA 94705Robert Rein3106 128th NEBellevue, WA 98005Eugeni o RetamalI di emUni versi dad De Chi 1 eCas1 11 a 1420SantiagoCHILERobert W. RetherfordInternational EngineeringP.O. Box 6410Anchorage, AK 99502Louis ReyLa JaquiereCH 1066 €pal i ngesSWITZERLANDCo.Ronald D. RhodehamelU.S. Fish and Wildlife Service3950 West Minster WayAnchorage, AK 99504John RichBechtel Petroleum Inc.716 Hillside AvenueAlbany, CA 94706James RichardsonBureau of Land Management701 C StreetAnchorage, AK 99513Ross D. Rieke3235 West Viewmont Way WestSeattle, WA 98199Daniel and Rosa1 i nd Ri seboroughCarl eton UniversityDept. of GeographyOttawa, K1S 5B6CANADABrad1 ey R i tchi eNational Park Service2525 Gambel StreetAnchorage, AK 99503Richard W. RobertsMineral Management ServiceP.O. Box 1159Anchorage, AK 99510Tom RobertsInstitute of Water Resources314 Duckeri ng Bui 1 dingUniversity of A1 askaFairbanks, AK 99701Scott RobertsonARCO Alaska Inc.P.O. Box 100360Anchorage, AK 99507Steve RogERTEC Northwest Inc.600 W 41st Street #203Anchorage, AK 99503Kevin E. Rogers2009 Westsi de DriveCleveland, TN 37311J. RomersbergerAlaska Dept. of Transportationand Public FacilitiesP.O. Box 60107Fairbanks, AK 99701Arthur 0. RonimusCrews, MacInnes, Hoffman, Vitro3812 Spenard Road, Suite 100Anchorage, AK 99503James W. and Florence RooneyR & M Consultants33925 Faerde BayLaguna Niguel , CA 92677W. R. Rouse (8-3)McMaster Uni versi tyDept. of Geography1280 Main Street WHamilton, Ontario L8A 4K1CANADAAkshai RunchalAnalytic Computational Research3106 Inglewood 61 vd.Los Angeles, CA 90066Steve RyanAlaska Dept. of TransportationXand Public FacilitiesPouch 6900Anchorage, AK 99502William L RyanOtt Water Engineering4790 Bussiness Park BD/SlAnchorage, AK 99503Bengt Erick RydenPhysical Geography DepartmentUppsala UniversityBox 554S75122 Uppsal aSWEDENWi11 i am Sacki ngerGeophysical InstituteUniversity of A1 askaFairbanks, AK 99701A. V. SadovskiResearch Institute of Foundationsand Underground, StructuresGosstroy-Niiosp2-A Institutskaja 6Moscow ZH389USSRLyn Sai nsbury4918 Silver Spruce LaneEvergreen, CO 80439J . Sal 1 stromAlaska Dept. of Transportationand Pub1 ic Faci 1 i ti esP.O. Box 60107Fairbanks, AK 99701John SandenLegend Dri 11 ServiceP.O. Box 65Galena, AK 99741Haakan SandstedtSwedish St Power Bd.S-16287 Vael 1 i ngbySWEDENBarry W. SantanaARCO Alaska, Inc.P .O. Box 100360Anchorage, AK 99510Francis H. and Dorothy SaylesCRREL72 Cyme RoadHanover, NH 03755

40 6Greg Scharfen (A-1)World Data Center/GlaciologyCIRES Campus Box 449Boulder, CO 80309Don SchellInstitute of Water ResourcesUniversity of AlaskaFairbanks, AK 99701Bob ScherEXXON Co., USAPouch 6601Anchorage, AK 99502John F. SchindlerHusky OilNPR2473 Captain Cook DriveAnchorage, AK 99503R. 0. SChleCht (A-1)Phi 11 ips Petroleum8055 E. Tufts Ave ParkDenver, CO 80237Mick SchlegelMcClelland-EBA, Inc.4649 Business Park Blvd.Anchorage, AK 99503Ruth A. Schmidt (B-6)1040 C StreetAnchorage, AK 99501Scott SchmidtARC0 A1 askaP.O. Box 100360Anchorage, AK 99503Lee and Kathleen B. SchoenArc0 Oiland Gas Co.P.O. Box 100939Anchorage, AK 99510Ekkehard SchunkeDept. of GeographyUni versi tit GtlttingenGoldschmidtstr 50-3400 GtlttingenWEST GERMANYW. Haeberl i Schwi t teSchutzenmott 718046 ZurichSWITZERLANDPeter C. ScorupP.O. Box 775Palmer, AK 99645William N. ScottRobertson and Associates2820 C. Street, Suite 2Anchorage, AK 99503Keith W. Scoular (8-4)1328 E. Lemon StreetPhoenix, AZ 85281James M. Scranton (A-2University of A1 askaFairbanks, AK 99701D. C. SegoDept. of Civil EngineeringUniversity of A1 bertaEdmonton, Alberta T6G 267CANADARich Sei fertInstitute of Water ResourcesUniversity of A1 askaFairbanks, AK 99701Bob SeitzInstrumentation Service124 2nd AvenueFairbanks, AK 99701Ken SellickF.W. Sawatsky Limited531 Marion StreetWinnipeg, Manitoba R2J OJ9CANADAPaul Sel lmannCRREL72 Lyme RoadHanover, NH 03755Arno Semmel (A-2)Theodor Koerer Str. 60-6238 Hofheim/TSWEST GERMANYStephen SeniukNordsen Industries5 Chester StreetWinnipeg, Manitoba R2L 1W5CANADAJohn SenykPacific Forest Research Center506 W. Burnside RoadVictoria, B.C. V8Z 1M5CANADAMatti Seppala (8-3)Department of GeographyUniversity of HelsinkiHal 1 i tusk 11-13 SF-00100Helsinki 10FINLANDCharles W. SeslarFederal Hi ghway Add ni strati onP.O. Box 1042Juneau, AK 99802Dick SewGulf Canada ResearchP.O. Box 310Calgary, Alberta T2P 2H7CANADALewis H. ShapiroGeophysical InstituteUniversity of A1 askaFairbanks, AK 99701Gus R. ShaverThe Ecosystems CenterMarine Biology LaboratoryWoods Hole, MA 02543Bi 1 1 Shef fi el dOffice of the GovernorPouch AJuneau, AK 99811Mark ShermanSR 20144-XFairbanks, AK 99701Richard G. Sherman (A-1)Metcalf & Eddy50 Stanford StreetBoston, MA 02114Shi Yafeng (A-2, 8-4)Lanzhou Institute of Glaclologyand Cryopedol ogyAcademia Si ni caLanzhouPEOPLE'S REPUBLIC OF CHINAE. M. ShoemakerSimon Fraser UniversityDept. of MathematicsBurnaby, Britfsh Columbia V5A 1S6CANADAHarold ShoemakerU.S. Dept. of EnergyP.O. Box 880Morgantown, WV 26505

40 7Carl SiebeA1 aska Dept. of Transportationand Publ ic Faci 1 i ti esPouch 6900Anchorage, AK 99502Ramesh SinghMitra Ni ketanBenaras Hindu Uni versi tyVaranasi - 221005INDIAA. K. SinhaGeological Survey of Canada601 Booth StreetOttawa, Ontario K1A OE8CANADAJames A. SiskBureau of Land ManagementP.O. Box 1150Fairbanks, AK 99707Stephen C. Si skAlaska Dept. of Transportationand Publ i c Faci 1 i ti es2301 Peger RoadFairbanks, AK 99701Charles S1 aughterU.S. Forest ServiceInstitute of Northern ForestryUniversity of AlaskaFairbanks, AK 99701Robert Sml thARCO Oiland GasP.O. Box 2819Dallas, TX 75221Scott SmithBox 2703Whitehorse, Yukon TerritoryCANADAStephen SmithDynatech BID Co.99 Erie StreetCambridge, MA 02139Gerhard Sonntag (A-1, 8-41Technical Universitat Mech CArci sstrasse 21D-8000 Munchen 2WEST GERMANYDavid Stan1 eyS & S Engineering, Inc.7127 Old Seward HighwayAnchorage, AK 99502Michael J. StanleyAlyeska Pipe1 Ine Service1835 S. Bragaw StreetAnchorage, AK 99512Co.Alex P. StansenStearns Roger Engi neeri ng Corp.Box 5888Denver, CO 80217Joe Sledge8450 Pioneer DrlveAnchorage, AK 99504 S. Russell & Lee H. StearnsCharles and Marilyn SloanU.S. Geological Survey1515 E. 13th AvenueAnchorage, AK 99501Made1 ei ne Smi th9 Francis DriveLaughborough, LE11ENGLANDMichael W. SmithDept. of GeographyCarl eton Uni versi tyOttawa, K1S 586CANADAOFEPeggy A. Smith (8-4)U.S. Geological Survey345 MIddlefi el d Road MS9OBMenlo Park, CA 94025Thayer SchoolDartmouth CollegeHanover, NH 03755of EngineeringCarl H. SteebyInternational Engineering Co.9271 Campbell Ter.Anchorage, AK 99502Jean SteinInstitute of Water ResourcesUniversity of A1 askaFairbanks, AK 99701George C. Stephens (A-1, 8-4Department of GeologyGeorge Washington UniversityWashington, O.C. 20550Eric and Helma StewartARCO 011 and Gas Co.P.O. Box 6105Anchorage, AK 99502Edward StondallNational Park Service2525 Gambell StreetAnchorage, AK 99503Michael G. 6. StonerMIS AR-10University of WashingtonSeattle, WA 98195Edward M. StramEarl & Wright Cons. EngineersOne Market PlazaSpear Street TowerSan Francisco, CA 94105Carl A. and M. Sam StrandeAnglo A1 aska ConstructionBox 10191 Curry 's CornerFairbanks, AK 99701Horst Strunk (A-2)Geographisches Ins ti tutder UniversitkitUniversidtsstr. 310-840 RegensburgWEST GERMANYRobert StuartOffice of the Federal Inspector1001 Noble StreetFairbanks, AK 99701Christopher W. StubbsQuaternary Research CenterUniversity of Wash1 ngton AK-60Seattle, WA 98195Edward and Maree Stuber (A-1)Assoc. Pile and Fit Corp.1750 Taylor St, Apt. 1102$an Francisco, CA 94133Juerg Suter (A-2, 8-4)Geophysical InstituteUniversity of ZurichPostfach 1 CH-8033ZurichSWITZERLANDHarald Svensson (8-3)Geophysical Jnsti tuteUniversity of CopenhagenHaral dsgade 68DK 2100 CopenhagenDENMARK

408Joe Svoboda (8-4)Dept. of BotanyUniversity of TorontoEri ndal e CampusMississauga, OntarioCANADAL5L 1C6Larry SweetAlaska Dept. of Transportationand Publ ic Faci 1 i ties2301 Peger RoadFairbanks, AK 99701Dan SwiftGeophysical InstituteUniversity of AlaskaFairbanks, AK 99701Charles Tarnocai (8-3)Land Resource Research Inst.K. W. Neatby BuildingCentral Experimental FarmOttawa, Ontario K1A OC6CANADARupert G. Tart6448 Village ParkwayAnchorage, AK 99504A1 an TaylorEarth Physics Branch1 Observatory Cres.Ottawa, K1A OY3CANADAR. 6. Taylor (6-6)Bedford Institute OceanographyBox 1006 DartmouthNova Scotia, B2Y 4AZCANADAA1 S. TelfordESSO Research Canada Ltd.237 Fourth Ave SWCalgary, A1 berta T5J 2R5CANADAJean and V. Terasmae (A-1)Brock University196 Woodside DriveSt. Catherines, Ontario L2T 1x6CANADAWilliam R. TheuerFairbanks Nati ve Association301 1st AvenueFairbanks, AK 99701Howard P. and Ingrid Thomas fed and Gloria Trueblood (A-1Woodward-Clyde ConsultantsA1 aska Rai 1 road12611 Brittany Drive 1621 Wintercrest DriveAnchorage, AK 99504 Anchorage, AK 99504Jim Thomas8101 Fai rwood Ci rcleAnchorage, AK 99502Dorothy H. ThompsonAlaska Department of NaturalResourcesP.O. Box 80368Fairbanks, AK 99708Grant R. and Iris ThompsonMobi 1 Research & Development Corp.320 E. Little Creek Rd.Cedar Hi1 1, TX 75104Thora E. fhorhall sdottir (A-2)Institute of BiologyUniversity of Ice1 andGrensasvegur 12ReykjavikICELANDColin E. Thorn (8-3)Dept. of GeologyUniversi ty of I1 1 i noi sUrbana, IL 61801Randall G. Updike (B-4)A1 aska Di vi si on of Geologicaland Geophysical Surveys3001 Porcupi ne DriveAnchorage, AK 997018. UrbanA1 aska Dept. of Transportationand Publ ic Faci 1 i tiesP.O. Box 60107Fairbanks, AK 99701Michael E. UttUnion OilCo. of CaliforniaP.O. Box 76Brea, CA 92621Keith Van CleveForest Soi 1 sUni versi ty of A1 askaFairbanks. AK 997010. A. Van Everdi ngen10 Hickory Street, E.Waterloo, Ontario N2J 4L4CANADAJules Ti 1 eston Robert A. Van Everdingen (B-3)Bureau of Land ManagementEnvironment Canada, NHRI701 C Street 101-4616 Valiant Drive NWAnchorage, AK 99513Calgary, A1 berta T3A OX9CANADAPhilip Tilley (A-2, 8-31Dept. of GeographyUniversity of SydneyNSW 2006AUSTRALIARichard0 A. A. TodeschiniBechtel Group Inc.P.O. Box 3965San Francisco, CA 94119Sahi n ToramanDOWL Engineers4040 B StreetAnchorage, AK 99504Zelma G. TraftonP.O. Box 1116Fairbanks, AK 99707Dou Van PattonSoi B Conservation ServiceP.O. Box 415Homer, AK 99605J. Vandenberghe (8-3)P.O. Box 71611007 MC AmsterdamTHE NETHERLANDSH. Vel dhui sCanada-Mani toba Soi 1 SurveyUniversity of ManitobaWinnipeg, Manitoba R3T 2N2CANADARalph P. Vendeland (A-1)EXXON Company USAP.O. Box 5025Thousand Oaks, CA 91359

409Leslie A. ViereckU.S. Forest ServiceInstitute of Northern ForestryUniversity of AlaskaFairbanks, AK 99701Ted S. VinsonDept. of Civil EngineeringOregon State UniversityCorvallis, OR 97331James C. Walters (8-4)Dept. of Earth ScienceUniversity of NorthernCedar Falls, IA 50614David W. H. Wal tonBritish Antarctic SurveyMadi ngl ey RoadCambridge, CB3 OETUNITED KINGDOMIowaFrancfs Weeks (A-1)A1 aska Rai 1 road3702 Alexander AvenueAnchorage, AK 99508P.C. WeerdenburgEBA Engineering Consultants Ltd.145535-118th AvenueEdmonton, A1 berta T5L 2M7CANADACharles L. VitaR & M Consultants#380-19700 Fai rchi 1 dIrvine, CA 92715John 0. Vitek (8-3)Dept. of GeologyOklahoma State UniversityStillwater, OK 74078David Vogel (8-4)A1 aska 05 VI si on of Geologicaland Geophysical Surveys794 University Ave. (Basement)Fairbanks, AK 99701David WalkerSohio Petroleum Co.100 Pine Street$an Francisco, CA 94111Dona1 d and Marilyn WalkerInst. Arctic Alpine ResearchUniversity of ColoradoBox 450Boulder, CO 80309Gerald WalkerGeophysical InstituteUniversity of A1 askaFairbanks, AK 99701H. Jesse Walker (8-6)Dept. of GeographyLoui si ana State UniversityBaton Rouge, LA 70803Kerry E. Walker2731 Delta CircleEagle River, AK 99577Henry Wal tersU.S. Army Corps of EngineersPouch 898Anchorage, AK 99506Wang Hong (A-1, 8-21Research Dl visionFirst Survey of Des Inst.Ministry of RailwaysLanzhouPEOPLE'S REPUBLIC OF CHINAWang Liang (A-2)Water Power ResearchInstitute74 Beian RoadChangchun. JilinPEOPLE'S REPUBLIC OF CHINARonald W. WardSohio Petroleum Co.5400 LBJ Freeway, Suite 1200/LB25Dallas, TX 75240A. Lincoln and Tahoe WashburnQuaternary Research Center #AK-60University of Washi ngtonSeattle, WA 98195T. Watari (8-6)NKK America Inc.444 S Flower Street, Suite 2430Los Angeles, CA 90017Wi11 iam J. and Naomi L. WayneDept. of GeologyUni versi ty of NebraskaLincoln, NB 68588Monte WeaverAlaska Dept. of Transportationand Pub1 1 c Faci 1 i ti esPouch 6900Anchorage, AK 99502Patrick Webber (A-2)Inst. Arctic Alpine ResearchUnl versl ty of ColoradoCampus Box 450Boulder, CO 80309Florence R. WeberU.S. Geological SurveyP.O. Box 80745Fairbanks, AK 99708E. WellenAlaska Dept. of Transportationand Public FacilitiesP.O. Box 60107Fairbanks, AK 99701Paul a We1 lenInstitute of Water ResourcesUniversity of A1 askaFairbanks, AK 99701Gunter We1 lerGeophysical InstituteUniversity of A1 askaFairbanks. AK 99701John WestgateUniversity of TorontoScarborough Campus1265 Military TROntario M1C 1A4CANADARuth L. and Raymond WexlerEngtneering Topographic Lab.9511 Linden AvenueBethesda, MD 20814W. Brian WhalleyDept. of GeographyQueens UniversityBelfast BT7 INNUNITED KINGDOMJohn R. WilliamsU .S. Geological Survey345 Mi ddl efiel d RoadMenlo Park, CA 94025Peter J. WilliamsDept. of GeographyCarl eton Uni versi tyOttawa, Ontario K1S 5B6CANADAR. B. G. Williams (8-3)Geography LabUniversity of SussexBri ghton, SussexUNITED KINGDOM

410James and Sandra Wil is (8-3)Anglo A1 aska Construction1/2 Mile Pebble DriveEster, AK 99725John Wi1 lmottOxford UniversityHertford CollegeOxford OX1 3BWUNITED KINGDOMJerry C. WilsonDames & Moore800 CordovaAnchorage, AK 99501M. J. WilsonUni versi ty of Colorado115 S 31stBoulder, CA 80303Monte D. WilsonDept. of Geology and GeophysicsBoise State UniversityBoise, ID 83725Peggy Winsl owEarth Science Dept.University of North CarolinaWilmington, NC 28406Ann WintleGodwi n LaboratoryCambridge UniversityCambridgeENGLANDMing-Ko Woo (8-3)Geography DepartmentMcMaster UniversityHamilton, Ontario L8S 4K1CANADAJohn WoodGeography Dept.Carleton Universi tyOttawa, Ontario K1S 5B6CANADAMi ng-Chee WuUniverslty of AlaskaFairbanks, AK 99701Tien Hsi ng and Pei HsingOhio State University2070 Neil AvenueColumbus, OH 43210WuA1 bert F. WuoriCRREL72 Lyme RoadHanover, NH 03755Xia Zhao JunDept. of Hydraulic EngineeringNortheast Agricultural Col 1 egeHarbin, HeilongjiangPEOPLE'S REPUBLIC OF CHINAXu Bomeng (A-2)Water Power Research Institute74 Beian RoadChangchun, JilinPEOPLE'S REPUBLIC OF CHINAXu XiaoruLanzhou Institute of G1 aci oloav -and Cryopedol ogyAcademia Si ni caLanzhouPEOPLE'S REPUBLIC OF CHINAEdward YarmakArctic Foundation Inc.5621 Arctic Blvd.Anchorage, AK 99503Edmond J. YarochAdh Coat & Sel Div-3M3M Center. Bulding 209-1C-13St. Paul , MN 55144Bing and Ann M. Yen (A-1)Dept. of Civil EngineeringCalifornia State UniversityLong Beach, CA 90840Kiyoshi YoneyamaTokyo Gas Co.. Ltd.16-25, Shibaura 1-ChomeMinatoku, Tokyo 105JAPANKi Ho YoonAlyeska Pipellne Service1835 S. Bra aw St.Anchorage, w K 99512Co.Yurii F. Zakharov (B-6)Tyumen GazpromU.S.S.R. Ministry of Gas IndustryNIIG Iprogaz, VPOTyumenUSSRBoris Zamsky (A-2)EXXON Production ResearchP.O. Box 2189Houston, TX 77001John P. ZarlingMechanical Engi neeri ngUniversity of AI askaFairbanks, AK 99701Co.Alvin Zeman (A-1)Rittenhouse-Zeman & Assoc.13837 NE 8th StreetBel levue, WA 98005Inc.John ZemanDept. of GeographyUniversity of BrStish ColumbiaVancouver, B.C. V6T 1R7CANADAZhao Yuehai (A-1, 8-21Foreign Affai rs BureauMinistry of RailwaysBei jingPEOPLE'S REPUBLIC OF CHINAZhao Yunlong (A-1, 8-21Institute of Railway SciencesQiqi harPEOPLE'S REPUBLIC OF CHINAZhou YOUWU (A-1, 8-4)Lanzhou Institute of G1 aciol ogyand Cryopedol owAcaderni a Si ni caLanzhouPEOPLE'S REPUBLIC OF CHINAZhu Qiang (A-2)Water Con Dept. Gansu ProvincePI-LI-HE, LanrhouGansuPEOPLE'S REPUBLIC OF CHINAZhu Yuan1 1 nLanrhou Institute of G1 aciol ogyand CryopedologyLanzhouPEOPLE'S REPUBLIC OF CHINAGary W. tielinskiDept. of Applied ScienceBrookhaven National Lab.Upto, NY 11973Paul ZiemanInstitute of Water ResourcesUnl versi ty of A1 askaFairbanks, AK 99701Winston ZirjacksFrank Moolin L Assoc.2525 C StreetAnchorage, AK 99503Chris ZubaUniversity of CalgaryES104/2500 University Dri ve NWCalgary, Alberta T2N 1N4CANADA

Afanasenko, V.E., 211Akimov, Yu. P., 195Anisimov, M.A., 200Anisimova, N.P., 318Are, A.L., 204Are, F.E., 87, 282, 318Bakshoutov, V., 208Balobaev, V.T.. 318Baluyura, M.V., 259Baulin, V.V., 318Berg, R.L., 67Blanchsrd, D., 321Blasco, S.M., 83, 321Boikov, S.A., 211Bondarenko, G. I., 317Brewer, M.C., 133Bruen, M.P., 322Brushkov, A.V., 248Calkin, P.E., 322ChekhovPkii, A.L., 318Chen Xiaobai, 55Cheng Guodong, 139Chervinskaya, 0.P. , 317Cheveryov, V.G., 195Danilova, N.S., 318Dashkov, A.G., 316Demidjuk, L.M., 217Demin, I.I., 316Destochers, D., 325Ding Jinkang, 18Dionne, J.-C., 321El'chaninov, E.A., 318Ellis, J.M., 322Ershov, E.D., 317Esch, D.C., 25Fedoseev, N.F., 222Fedoseeva, V.I., 222Ferrians, 0. J., Jr., 97, 98Fotiev, S.M., 315Fremond, M., 321French, H.M., 129Fursov, V.V., 259Gagarin, V.E., 317Galloway, J.P., 323Gavrilov, A.N., 316Gavrilova, M.K., 226Ginsburg, E.D., 273Eorbunov, A.P., 318Gorskaya, G.S. ,217Grave, N.A., 116, 188, 316Gray, J.T., 156, 322, 324Grechishchev, S.E., 52, 316Grigoryev, N.F., 319Grltsenko, A.I., 167Gulko, E. F., 300Hayley, D.W.,Hemming, J.E.,93113Hopkins, D.M. 73, 75Hunter, J.A.M., 88Author IndexInosemtsev, V.K. , 231Ivanov, V.N., 316Ivaschenko, I.N., 306Jahns, H.O. , 90, 101Johnson, E.R., 109Judge, A., 137, 324, 325Jumikis, A.R., 333Kamensky, R.M., 264Karlov, V.D., 231Katasonov, E.M., 318Khrustalev, L.N., 317King, M.S., 323Knutsson, S., 323Kolesnikov, S.F., 317Kolesov, A.A., 316Komarov, LA., 236Kondakova, O.A. , 248Konishchev, V.N., 317Konstantinov, I. P. , 264Koster, E.A., 323Kosukhin, L.D., 173Kotov, P.B., 300Kritzuk, L.N., 318Krivoshein, B.L., 242Kronik, Ya.A., 316Kudryavtsev, V.A., 315, 319Kuleshov, YU.~., 248Kutvitskaya, N.B., 316Kuzmin, R.O., 319Ladanyi, B., 43Latalin, D.A., 317Lauriol, B., 324Lebedenko, Yu.P., 248tong, E.L., 325Makarov, V.N., 253Makihara, J.S.,Makogon, Yu.F.,324167Maksimyak, R.V., 316Malevskii-Malevich, S.P., 317Malyshev, M.A., 259Martynova, G.P., 316Mathews, LC., 100McVee, C.V., 125Melnikov, P.I., 163, 264, 315,316Merzlyakov, V.P., 300, 316Metz, M.C., 106Miller, R.D., 61Misnyck, Yu.M., 268Morgenstern, N.R., 15Moskalenko, N.G. , 31 7Nanivskiy, Ye.M,, 173Nechaev, E.A., 222Neizvestnov, Ya. V. , 273Nelson, G.E., 327O'Connor, M.J., 321Osterkarnp, T.E., 145Pakhomova, G.M., 278Parmuzina, O.Yu., 318Pavlov, A.V., 282, 318Penner, E. , 51Petrov, V.S., 248, 268Phukan, A., 325Pilon, J., 137, 322, 324Poitevin, J., 322, 324Poleshuk, V.L, 286Popov, A.1, 316Plotnikov, A.A., 316Rogov, V.V., 317Roman, L.T., 290Romanovskil, N.N., 31 5Rosenbaum, G.E. , 317Rozhdes tvenskii, N.Yu. , 31 7Ryabets, N.I., 268Sadovskiy, A.V., 186, 317Savel'ev, B.A., 317Sayles, F.H., 31Sellmann, P.V., 73, 75Shepelev, V.V., 319Shevchenko, L.V., 248Shonin, O.B., 268Shur, Yu.~., 317Shusherina, E.P., 306, 316Shvetsov, P.F., 317, 319Slavin-Borovskii, V.B., 317Slepak, M.E., 316Smith, M., 153Snegirev, A.M., 295Soloviev, V.A., 273Spiridonov, V.V., 217Takasugi, S., 325Tankayev, R.U., 200Taylor, A.E., 324, 325Tikhomirov, S.M., 316Tileston, J.V., 125Timof eyev, V. M. , 2 11Tsytovich, N.A., 316Ukhov, S.B., 300Ulantsev, A.D., 200Van Cleve, K. , 325Velichko, A.A., 318Viereck, L.A., 325Voitkovsky, K.F., 264Vrachev, V.V., 306Vyalov, S.S., 16, 177, 316Webber, P.J., 135Williams, D., 326Williams, P.J., 64Yarmak, E., Jr., 325Yershov, E.D., 195Yershov, V.D., 248Zakharov. Yu.F., 173Zhestkova, T.N., 318Zhigarev, L.A., 311, 318Zykov, Yu.D., 317

Available Publications of InternationalPermafrost ConferencesNational Research Council, 1966. Permafrost: International Conference Proceed-&. NRC Pub. 1287. Washington, LC.: National Academy of Sciences.Available on microfilm in The Cold Regions Science and Technology Bibliography625-3138, U.S. Library of Congress or NTIS.National Academy of Sciences, 1973. Permafrost: The North American Contributionto the Second International Conference; Yakutsk. Washington, LC.: NationalAcademy of Sciences. $50.00National Academy of Sciences, 1978. Permafrost: USSR Contribution LO the SecondInternational Conference. Washington, D.C.: National Academy of Sciences.$19.50National Research Council of Canada, 1978. Proceedings of the Third InternationalConference on Permafrost, 2 volumes. Ottawa, Ontario: National ResearchCouncil of Canada. $35.00National Research Council of Canada, 1980. Third International Conference onPermafrost, Enqliah Translationstario: National Research Councilof the Soviet Papers,of Canada. $35.002 parts. Ottawa, On-University of Alaska, 1983. Permafrost: Fourth International Conference. Abstractsand Program. Fairbanks: University of Alaska. $10.00National Academy of Sciences, 1983. Permafrost: Fourth International Conference,Proceedings. Washington, LC.:National Academy of Sciences, 1984.National Academy Press. $65.00Permafrost: Fourth International Conference,Final Proceedings. Washington, D.C.: National Academy Press. $32.50.Permafrost: A Bibliography, 1978-1982. Glaciological Data Report GD-14, Boulder,World Data Center for Glaciology, 1983, 172 p., $5.00. (University of Colorado,Box 449, Boulder, Colorado 80309)413