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

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