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Figure 3.10: Recommended Cyclic Resistance Ratio (CRR) for Clean Sands Under Level Ground Conditions
Based on CPT.....................................................................................................................................64
Figure 3.11: Cyclic Resistance Curves for Silty Soils from Various Sites in the Pacific Northwest..........................68
Figure 3.12: Influence of Overconsolidation Ratio on the Cyclic Resistance of a Marine Sand................................70
Figure 3.13: Influence of Fines Content and Overconsolidation Ratio on the Cyclic Resistance of Sands and Silts.71
Figure 3.14: Effects of Plasticity Index on Cyclic Strength of Silty Soils..................................................................71
Figure 3.15: Variation of Equivalent Uniform Loading Cycles with Earthquake Magnitude ....................................72
Figure 3.16: Relationship Between Residual Excess Pore Pressure and Factor of Safety Against
Liquefaction (FS L ) for Level Ground Sites.........................................................................................73
Figure 4.1: Normalized Residual Strength Plotted against Plasticity Index ...............................................................77
Figure 4.2: Charts Relating (a) Normalized Standard Penetration Resistance (N 1 ) 60 ; and (b) Residual
Shear Strength S r to Vertical Effective Overburden Pressure σ′ vo , for Saturated
Non-gravelly Silt-Sand Deposits that have Experienced Large Deformations...................................79
Figure 4.3: Undrained Critical Strength Ratio Versus Equivalent Clean Sand Blow Count ......................................80
Figure 4.4: Relationship Between Residual Strength and Corrected SPT Resistance ................................................81
Figure 4.5: (a) Relationship between Thickness of Liquefiable Layer and Thickness of Overlying Layer
at Sites for which Surface Manifestation of Liquefaction has been Observed, and
(b) Guides to Evaluation of Respective Layer Thicknesses................................................................84
Figure 4.6: Variation of LSI with Distance and Earthquake Magnitude ....................................................................86
Figure 4.7: Comparison of Computed Lateral Spread Displacements with Observed Displacements .......................88
Figure 4.8: Overview of EPOLLS Model for Predicting Average Horizontal Displacement in Meters ....................90
Figure 4.9: Elements of Sliding Block Analysis ........................................................................................................91
Figure 4.10: Model of Hypothetical Slope. ................................................................................................................92
Figure 4.11: Empirical Relationships between Permanent Displacement of Sliding Block and Ratios of
Accelerations ......................................................................................................................................93
Figure 4.12: Post Volumetric Shear Strain for Clean Sands.......................................................................................96
Figure 4.13(a): Factor of Safety versus Volumetric Strain for Undisturbed Silt Specimens ......................................97
Figure 4.13(b): Factor of Safety versus Volumetric Strain for Reconstituted Silt Specimens....................................97
Figure 4.14: Chart for Estimation of Volumetric Strain in Saturated Sands from Cyclic Stress Ratio and Standard
Penetration Resistance........................................................................................................................98
Figure 4.15: Potential Modes of Pile Failure Due to Lateral Loading by Liquefied Soil ...........................................99
Figure 5.1: Improvement Area for Gravity Retaining Structures .............................................................................106
Figure 5.2: Improvement Area for Pile Foundation and Underground Structure .....................................................106
Figure 5.3: Models of Embankments in Clayey Sand Underlain by Liquefiable Sands...........................................107
Figure 5.4: Results of Model Testing of Embankments ...........................................................................................108
Figure 6.1: Basic Explicit Calculation Cycle............................................................................................................109
Figure 6.2: Modeled Liquefaction Resistance Curve................................................................................................111
Figure 7.1: Newmark Displacement as a Function of Arias Intensity for Several Values of Critical Acceleration .120
Figure 7.2: Illustration of Bracketed Intensity..........................................................................................................122
Figure 7.3. Bracketed Intensity versus (PGA – a crit ) as a Function of PGA .............................................................123
Figure 7.4: Newmark Displacement versus Bracketed Intensity..............................................................................123
Figure 7.5: Generalized Geometry for Dynamic Analysis of Soil Adjacent to Bridge Foundations ........................125
Figure 7.6: Acceleration Time Histories Used in Parametric Study.........................................................................129
Figure 7.7: Displacement versus Static, Post-earthquake Factor of Safety ..............................................................133
Figure 7.8: Displacement versus Static, Post-Earthquake Factor of Safety as a Function of Ground
Motion Intensity Factor (GMI).........................................................................................................134
Figure 7.9: Comparison of Methods for Estimating Earthquake-Induced Displacements........................................135
Figure 8.1: Flow Chart for Evaluating and Mitigating Liquefaction Hazards ..........................................................141
Figure 8.2: Illustration of Cascadia Subduction Zone ..............................................................................................146
Figure 8.3: Portland Area Faults...............................................................................................................................147
Figure 8.4: Contours of PGA on Rock with a Return Period of 500 Years for Northwestern Oregon.....................148
Figure 8.5: Representative Cross-Section of the Columbia River Levee along Marine Drive .................................150
Figure 8.6: Aeropuerto and Ofunato (Scaled PGA = 0.12g) Response Spectra Compared to the Magnitude 8.5
Cascadia Subduction Zone Target Spectrum on Rock......................................................................152
Figure 8.7: Aeropuerto and Ofunato (Scaled PGA = 0.14g) Response Spectra Compared to the Magnitude 9.0
Cascadia Subduction Zone Target Spectrum on Rock......................................................................153
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