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

More documents

Recommendations

Info

46the development schedule has not been determined during the design stage, the designershould liaise with relevant government departments or land developers and determine asuitable time interval after completion of reclamation for calculating the target residualsettlement. In any case, the designer should check with those bodies to see if there are anyspecial settlement requirements.For a typical reclamation in Hong Kong where the seabed is underlain by marine and alluvialclay, the following information may assist the designer to assess the residual settlement:• If the reclamation is near the shore where the thickness of the clay layer isabout 5 to 8 m, it is usually practical to limit the residual settlement arisingfrom primary consolidation to 50 mm for the drained method with preloadingand a reasonably tight construction programme.» If the reclamation extends to deep waters, with clay layer of about 20 m ormore, residual settlement of 250 mm can generally be achieved. The amountcan be further reduced by over-consolidation with additional surcharge, but thecost will be higher and the construction period will be longer. Overconsolidationwill also reduce the secondary consolidation, particularly for softmud.• The residual settlement due to creep of granular fill, with thickness of 10 to15 m in a typical reclamation, may be in the order of a few hundred millimetres.Treatment of the fill by the methods mentioned previously may be necessary toachieve the target residual settlement.The thickness and properties of the soil, the period of fill placement and fill treatment varyacross a reclamation site.Therefore, it is necessary to estimate the residual settlement indifferent portions of the reclamation to account for such variability.Where the presence ofmud lenses is suspected in the underlying strata, additional ground investigation should becarried out to identify their locations and to determine relevant soil parameters for settlementanalysis.Where the designer considers that resiltation of clayey or silty particles of the dredged soil isa problem at a particular site, its effect on settlement should be assessed.The amount of residual settlement estimated in the design stage should be verified by fieldmonitoring data (see Chapter 5 of this part of the Manual).
47The calculation of residual settlement for a reclamation is subject to many variables fromground conditions to analytical methods and construction processes. Different practitionersmay come up with a different value at the same location due to different assumptions. Anappropriate degree of accuracy of the calculated settlement should be indicated in the designreports and technical correspondence.
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: 45H = Fill thickness.a = Logarithmi
Page 52 and 53: 50For monitoring of pore pressure d
Page 54 and 55: 525.3.2 of FillThis section discuss
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?