PORT WORKS DESIGN MANUAL PART 3 Guide To - The University ...

More documents

Recommendations

Info

525.3.2 of FillThis section discusses the methods of plotting the collected monitoring data to assist in theassessment of the interim stability of the reclamation process. However, other siteobservations will also be useful indicators of the reclamation stability such as:® Tension cracks appearing at the top and side slope of the reclamation.• Settlement at the centre of reclamation increasing rapidly.• Sounding survey results indicating up and down curve profiles of the seabednear the edge of the reclamation.» Filling rate increasing suddenly.• Fill being stockpiled on the site excessively.Monitoring data should be taken at least daily and given to the engineer immediately toenable any anomalous behaviour to be discovered as early as possible.(1) w-
53Ye et al (1997), the data set Ah, A8 H and h can be used to estimate the maximum allowableheight of fill. There is a consistent relationship between Ah/A8 H and h as shown inFigure 13. When h is small, Ah/AS H is large. As h gets larger, the relationship betweenAh/AS H and h will tend to become linear. If this straight portion is projected towards the h-axis, the intercept will give the predicted maximum height of filling. The height of fillshould not exceed this value until after consolidation of the mud layer (checked bymonitoring pore pressures).5.3.3 Verification of Settlement Based on Field Monitoring DataThe principle of verification of settlement involves back-analysis of field monitoring data.This can be carried out by fitting different values of coefficient of consolidation (vertical andhorizontal) into the consolidation equations and comparing the resultant settlement-timerelationships with the actual settlement-time curve plotted from field settlement data. BothTerzaghi's one-dimensional consolidation theory and Barren's radial consolidation theory forvertical and horizontal drainage respectively can be applied in the back-analysis (seeAppendix B). The process of curve fitting is a trial and error process which can be speededup with the use of computer programmes incorporating the appropriate consolidationequations and assumptions. Wai and Lam (2001) may be referred to for more details ofback-analysis by curve fitting.Alternatively, a method developed by Asaoka (1978) also enables utilization of the settlementmonitoring data, through simple graphical means, to verify the settlement due to primaryconsolidation calculated in the design stage. The principles and details of application of themethod are given in Appendix C. The results provide additional information for thedesigner to assess the settlement condition of the reclamation.Asaoka's method is based on observational settlement prediction. Field settlement datameasured by settlement plates at the seabed or, if not practicable, at the surface of thedrainage blanket, are plotted in accordance with the method given in Appendix C. Theplotted results give an estimate of total primary consolidation settlement of the soil beneaththe seabed, which can then be compared with the total primary consolidation settlementpredicted at the design stage. The residual settlement can also be re-assessed with referenceto the ultimate primary consolidation settlement estimated from Asaoka's Method and thefield settlement data measured at a particular time, say, at the time of completion of fillingworks or handing over the site.Asaoka's method has the advantage that it is simple to use.However, it relies very much on
Page 3 and 4: PORT WORKS DESIGN MANUALPART 3Guide
Page 5 and 6: FOREWORDThe Port Works Design Manua
Page 7 and 8: CONTENTSTITLE PAGE - !FOREWORD 3CON
Page 9: PageNo.5.3.3 Verification of Settle
Page 12 and 13: 101.2 Definition, Symbols and Refer
Page 14 and 15: 12the investigations may need to co
Page 16 and 17: 14consequences of adopting a partic
Page 18 and 19: 16(3) Installation of vertical drai
Page 20 and 21: 18The remaining layer of marine or
Page 22 and 23: 20• The rate of supply of public
Page 24 and 25: 22the shortage of public filling ca
Page 26 and 27: 24Considerations when planning the
Page 28 and 29: 262.10 Environmental ImpactsAll rec
Page 31 and 32: 293.3.1 GeneralThe reclamation sequ
Page 33 and 34: 31requires checking of the equilibr
Page 35 and 36: 33(2) Detailed Stability AnalysisTh
Page 37 and 38: 3.4 WorksIf, despite all the precau
Page 39 and 40: 374.4.1 GeneralThis chapter discuss
Page 41 and 42: 3943.2 due toThe ultimate primary c
Page 43 and 44: 41where S pt(residml) = Residual se
Page 45 and 46: Design of surcharge preloading gene
Page 47 and 48: 45H = Fill thickness.a = Logarithmi
Page 49: 47The calculation of residual settl
Page 52 and 53: 50For monitoring of pore pressure d
Page 56 and 57: 54the availability of frequent moni
Page 58 and 59: 56reduce settlement problems. Howev
Page 61 and 62: 59REFERENCESAsaoka, A (1978). Obser
Page 63: 61FIGURES
Page 67 and 68: 65(1) Geotextile-\I,- i i i i i , ,
Page 69 and 70: 67Figure 5 - Method of Calculation
Page 71 and 72: 69timet + 120Piezometer installed a
Page 73 and 74: 71Slope >1Required pause in fill pl
Page 75: 73APPENDIX APREFABRICATED BAND DRAI
Page 78 and 79: 76List of ASTMD4491-92: Standard Te
Page 81: 79CONTENTSTITLE PAGE 77CONTENTS 79B
Page 84 and 85: 82t = Time from load application.c
Page 86 and 87: 84Hansbo, S. (1981).Consolidation o
Page 89 and 90: 87CONTENTSTITLE PAGE 85CONTENTS 87C
Page 91 and 92: 89C OF BY ASAOKA'S METHODC.IGeneral
Page 93: 91OFFigureNo.PageNo.C1 Asaoka's Gra
Page 96 and 97: 94SiFinal settlementPlacement of. a
Page 99: 97CONTENTSTITLE PAGE 95CONTENTS 97D
Page 102 and 103: 1000.3(8.9)(3 2 )(1. 2) - 2.8836L e
Page 104 and 105:
102Vertical drains dataTypeSpacingP
Page 106 and 107:
104The final primary consolidation
Page 108 and 109:
106The initial effective stress at
Page 110 and 111:
108Table D2.6m0123M0.5711.5712.5713
Page 112 and 113:
110Effective stress increment at en
Page 114 and 115:
112(3) Settlement due to secondary
Page 116 and 117:
114The value ofF(n) in Example D.2
Page 118 and 119:
116
Page 120 and 121:
118CD~5COCOCDCLCD20 -14.9Required p
Page 122 and 123:
120
Page 124 and 125:
122state value.Mud wave. Excessive
Page 126 and 127:
124
Page 128 and 129:
126dd'D ree 0e maxe minFHI pK aLeng
Page 130 and 131:
128
Page 132:
X1S1SD112HK 627.5 P83Port works des
show all

PORT WORKS DESIGN MANUAL PART 3 Guide To - The University ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?