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

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112(3) Settlement due to secondary consolidation in marine depositThe residual settlement due to secondary consolidation is:^/(residual) ~ C a£ H.\Og( ~ °l \l o= 0.005x 10.0xlog(5 ° 9 ' 5/12 )22/12-9.5/12= 84 mm(4) Settlement within reclamation fillDue to the primary settlement, the thickness of the reclamation fill is taken to be 15.5m.The residual settlement of reclamation fill due to creep at end of 22 nd month:^.(residual) =//« lOg(50-^t—±2^-),_ nni , , 50-9/2/12= 15.5 x O.Olx log( )22/12-9/2/12= 237 mm(5) Residual settlement at end of 22 nd monthTotal residual settlement at the time of removal of surcharge is estimated to be~ ^s,p(residual) + ^s,t(residual) + Sc,t(residual)= 25 + 84 + 237-350 mm
113D.3 Example 3 - Monitoring of Pore Pressure for Stability during Fill PlacementGivenA piezometer installed in the marine deposit layer revealed abnormalities during the fillplacement works. Increase of excess pore water pressure was found larger than thepredicted value as shown in Figure D2. Pause of filling works was considered necessary(see Section 5.3.2).The dimensions of vertical drains were the same as those in Example D.2. The coefficientof consolidation (horizontal) was taken as 1.5m 2 /year.TaskEstimate the time required (f) for the excess pore water pressure to fall back to the normalmagnitude.Approach(1) Define the abnormal excess pore pressure as the initial excess pore pressure (M O ).(2) Define the target normal excess pore pressure (u e \(3) Determine the required degree of consolidation (U h ) for dissipation of excess porepressure from u 0 to u e .(4) Back calculate the time factor (T h ) from the required U h .(5) Obtain the actual time t required from T h .SolutionInitial excess pore pressure, u 0 = 20.0 kN/m 2 (see Figure D2)Excess pore water pressure at time t, u e = 14.9 kN/m 2 (see Figure D2)Pore pressure to be dissipated, d p = 20.0 - 14.9 = 5.1 kN/m 2Neglecting vertical drainage, average degree of consolidation required to dissipate the abovepore pressure is given by:[/ =11 = 0.255* 20
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PORT WORKS DESIGN MANUALPART 3Guide
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FOREWORDThe Port Works Design Manua
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CONTENTSTITLE PAGE - !FOREWORD 3CON
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PageNo.5.3.3 Verification of Settle
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101.2 Definition, Symbols and Refer
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12the investigations may need to co
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14consequences of adopting a partic
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16(3) Installation of vertical drai
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18The remaining layer of marine or
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20• The rate of supply of public
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22the shortage of public filling ca
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24Considerations when planning the
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262.10 Environmental ImpactsAll rec
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293.3.1 GeneralThe reclamation sequ
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31requires checking of the equilibr
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33(2) Detailed Stability AnalysisTh
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3.4 WorksIf, despite all the precau
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374.4.1 GeneralThis chapter discuss
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3943.2 due toThe ultimate primary c
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41where S pt(residml) = Residual se
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Design of surcharge preloading gene
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45H = Fill thickness.a = Logarithmi
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47The calculation of residual settl
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50For monitoring of pore pressure d
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525.3.2 of FillThis section discuss
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54the availability of frequent moni
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56reduce settlement problems. Howev
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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 116 and 117: 114The value ofF(n) in Example D.2
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Page 120 and 121: 118CD~5COCOCDCLCD20 -14.9Required p
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Page 124 and 125: 122state value.Mud wave. Excessive
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Page 128 and 129: 126dd'D ree 0e maxe minFHI pK aLeng
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Page 132: X1S1SD112HK 627.5 P83Port works des
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