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liquefiable (Chang 1990). Finn and others (1994) provide a review of the design and analysis of structures in potentially liquefiable silty soils. In addition to sandy and silty soils, some gravelly soils and even rockfills are potentially vulnerable to liquefaction. A number of well-documented field case histories (Prakash and Dakoulas 1994) confirm that gravelly soils can liquefy. In recent years, the liquefaction behavior of gravelly soils has been investigated in the laboratory. The results and implications of these tests have been summarized by Evans and Zhou (1994). Most coarse, gravelly soils are relatively free draining; if the voids are filled with finer particles, or the surrounded soils are less pervious, then drainage may be impeded and cyclic pore pressure generation or liquefaction becomes more likely. Similarly, when they are of considerable thickness and lateral extent, deposits of coarse gravelly soils may not be capable of dissipating pore pressures and may be vulnerable to potential liquefaction. Field evidence has shown that most liquefied gravelly soils are sand-gravel composites (Harder and Seed 1986; Evans and Harder 1993). Evans and Zhou (1994) present the results of cyclic triaxial tests on soils with increasing percentages of gravel content. They conclude that sandgravel composites show an increase in cyclic strength with increased gravel content, even though the relative density of the composite is constant. This result raises questions about the relationship between laboratory test results and actual field behavior. Currently, the best techniques available for quantitative evaluation of the liquefaction resistance of coarse gravelly soils are those described by Harder (1988), Harder and Seed (1986), and several papers contained in Prakash and Dakoulas (1994). These methods involve two primary evaluation procedures: (1) the use of very large-scale Becker Hammer penetration resistance correlations, or (2) corrections to penetration resistances obtained by the SPT. Application and support for the former method is provided by Harder (1994), and Lum and Yan (1994), where case histories are provided to examine the application of the Becker penetration test for characterizing the liquefaction potential of gravelly soils. In assessing the potential presence of liquefiable soil types, investigations should extend to a depth below which liquefiable soils cannot be reasonably be expected to occur. Field evidence, as observed in the Kobe and Loma Prieta earthquakes, has shown that liquefaction may occur to depths of 18.5 m. Liquefaction resistance can be roughly correlated with geologic age, depositional environment, and prior seismic history. Tables 3.1 through 3.3 present examples of geologic (and topographic) bases for preliminary estimation of liquefaction susceptibility, as summarized by Youd (1991). Generally, geologically young natural sandy formations are most susceptible to liquefaction. Such deposits can be found in offshore, coastal, or floodplain areas when deposits are formed by the soil particles settling through water and coming to rest in a very loose state. This means that the latest Holocene deposits, typically related to the natural drainage network, are most susceptible to liquefaction. Deposits older than late Pleistocene are assumed to be not susceptible to liquefaction, based on their performance during earthquakes. 42
Table 3.1: Estimated Susceptibility of Sedimentary Deposits to Liquefaction during Strong Seismic Shaking (Youd and Perkins 1978) Types of deposit General distribution of cohesionless sediments in Likelihood that cohesionless sediments, when saturated. would be susceptible to liquefaction (by age of deposit) deposits
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ASSESSMENT AND MITIGATION OF LIQUEF
Page 5 and 6: ACKNOWLEDGMENTS The authors would l
Page 7 and 8: ASSESSMENT AND MITIGATION OF LIQUEF
Page 9 and 10: 8.0 HAZARD EVALUATION AND DEVELOPME
Page 11 and 12: LIST OF FIGURES Figure 1.1: ODOT’
Page 13: Figure 8.8: Long Valley Dam and Lak
Page 16 and 17: Design of a given component shall l
Page 18 and 19: Liquefaction Mitigation Procedure G
Page 20 and 21: Pacific Northwest also are summariz
Page 23 and 24: 2.0 OVERVIEW OF LIQUEFACTION-INDUCE
Page 25 and 26: oughly 50 centimeters, with numerou
Page 27 and 28: supported bridges along the Seward
Page 29 and 30: Another area of extensive bridge da
Page 31 and 32: Nineteen bridges were also damaged
Page 33 and 34: 1. No foundation failures were obse
Page 35 and 36: piles supporting the fourth pier, l
Page 37 and 38: Figure 2.17: Observed Pile Deformat
Page 39 and 40: Figure 2.19: Damage from the 1906 S
Page 41 and 42: Figure 2.22: Ground Deformations Ne
Page 43 and 44: induced ground displacement was the
Page 45 and 46: Well-documented case histories of t
Page 47 and 48: Similar damage to pile foundations
Page 49 and 50: Examples of acceptable bridge found
Page 51 and 52: Numerous investigations of liquefac
Page 53 and 54: 3.0 EVALUATION OF LIQUEFACTION SUSC
Page 55: The evaluation of liquefaction haza
Page 59 and 60: movements, or localized ground disp
Page 61 and 62: Shear wave velocities can now be ob
Page 63 and 64: 3.4 LIQUEFACTION RESISTANCE: EMPIRI
Page 65 and 66: Figure 3.1: Range of r d Values for
Page 67 and 68: The earthquake-induced shearing str
Page 69 and 70: drill rod during hammer impact. In
Page 71 and 72: Figure 3.5: Minimum Values for K σ
Page 73 and 74: 3.4.2.2.1 CPT Method Developed by R
Page 75 and 76: 1. Sensitive, fine grained 6. Sands
Page 77 and 78: Figure 3.9: CPT-Based Curves for Va
Page 79 and 80: CRR where: q c 2 3 0.00128 0.0
Page 81 and 82: Tacoma, Washington (Dickenson and B
Page 83 and 84: Table 3.8: Influence of OCR on the
Page 85 and 86: Figure 3.13: Influence of Fines Con
Page 87: Gravel Sand Figure 3.16: Relationsh
Page 90 and 91: FS L > 1.4: Excess pore pressure ge
Page 92 and 93: The post-liquefaction strength of s
Page 94 and 95: Figure 4.3: Undrained Critical Stre
Page 96 and 97: 4.3 INTRODUCTION TO MODES OF FAILUR
Page 98 and 99: Figure 4.5: (a) Relationship betwee
Page 100 and 101: not available for many case studies
Page 102 and 103: provided to give the recommended ra
Page 104 and 105: Figure 4.8: Overview of EPOLLS Mode
Page 106 and 107:
Figure 4.10: Model of Hypothetical
Page 108 and 109:
4.5.2 Advanced Numerical Modeling o
Page 110 and 111:
Figure 4.12: Post Volumetric Shear
Page 112 and 113:
The relationship shown in Figure 4.
Page 114 and 115:
A third type of failure is shown in
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Table 5.1: Liquefaction Remediation
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5.3 DESIGN OF SOIL MITIGATION The d
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soil improvement guidelines state t
Page 122 and 123:
The models were instrumented with a
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The model uses an explicit method,
Page 126 and 127:
A simplification was made in the mo
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permanent earthquake displacements)
Page 130 and 131:
7.0 DEFORMATION ANALYSIS OF EMBANKM
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engineers; (2) requisite input incl
Page 134 and 135:
π g 2 a t I a 2 dt (7-1) The A
Page 136 and 137:
10 1 Bracketed Intensity (m/s) 0.1
Page 138 and 139:
7.3 PARAMETRIC STUDY A well-validat
Page 140 and 141:
the rigid body methods. The point a
Page 142 and 143:
0.4 Acceleration (g) 0.2 0 -0.2 -0.
Page 144 and 145:
Embankment Height (m) Depth of Liqu
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10 1 DISPLACEMENT (m) 0.1 Morgan Hi
Page 148 and 149:
2.0 Embankment Toe Embankment Mid-S
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suitably reliable estimates of perm
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interest. Specifically, the peak be
Page 155 and 156:
Flow Chart for Evaluation and Mitig
Page 157 and 158:
The deformation evaluations were pe
Page 159 and 160:
Portland (a) (b) Figure 8.2: Illust
Page 161 and 162:
Figure 8.4: Contours of PGA on Rock
Page 163 and 164:
Borehole 4E CPT Hole 4E 26.0' NGVD
Page 165 and 166:
8.4.2 Subduction Zone Bedrock Motio
Page 167 and 168:
154 Table 8.5: Selected Acceleratio
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Spectral Acceleration (g) 1.50 1.40
Page 171 and 172:
with the calculated equivalent unif
Page 173 and 174:
n ( M 10 1) (8-1) where M is the
Page 175 and 176:
0.20 0.15 0.10 Acceleration (g) 0.0
Page 177 and 178:
15.0 12.5 10.0 Long Valley Dam Lake
Page 179 and 180:
CSR should be modified for the pres
Page 181 and 182:
8.7 EVALUATION OF INITIATION OF LIQ
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crest stage Marine Drive 42.5 ft NG
Page 185 and 186:
Table 8.9: Fines Content Values Est
Page 187 and 188:
large sliding and long-term disrupt
Page 189 and 190:
Table 8.12: Deformation Results fro
Page 191 and 192:
The earthquake time histories used
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North (river) South (land) North To
Page 195 and 196:
Table 8.20: Riverward Deformation R
Page 197 and 198:
applications (DDC, closely spaced v
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Table 8.21: Comparison of Predicted
Page 202 and 203:
9.0 SUMMARY AND CONCLUSIONS Recent
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dewatering may be warranted. Additi
Page 207 and 208:
Bardet, J.P. (1990). “LINOS - A N
Page 209 and 210:
California Division of Mines and Ge
Page 211 and 212:
Fujii, S., M. Cubrinovski, K. Tokim
Page 213 and 214:
Ishihara, K. and M. Cubrinovski. (1
Page 215 and 216:
Liu, A.H. and J.P. Stewart. (1999).
Page 217 and 218:
Oregon Department of Transportation
Page 219 and 220:
Schnabel, P., J. Lysmer, and H.B. S
Page 221 and 222:
Sun, I.H. and I.M. Idriss. (1992).
Page 223:
Youd, T.L. and C.F. Jones. (1993).
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