Soil Liquefaction

Introduction What is this book about? Why a critical-state view? Experience of liquefaction Outline of the development of ideas Dilatancy and the state parameter Framework for soil behaviour State parameter approach Evaluating soil behaviour with the state parameter Determining the critical state Uniqueness of the CSL Soil properties Plane strain tests for soil behaviour General soil behaviour from triaxial properties Constitutive modelling for liquefaction Introduction Historical background Representing the critical state Cambridge view State parameter view NorSand constitutive model Comparison of NorSand to experimental data Commentary on aspects of NorSand Determining state parameter in situ Introduction SPT versus CPT Inverse problem: A simple framework Calibration chambers Stress normalization Determining I from CPT Moving from calibration chambers to real sands Elasticity in situ Horizontal geostatic stress Alternative in situ tests to the CPT Commentary on state determination using the CPT Soil variability and characteristic states Introduction Effect of loose pockets on performance Effect of variability of in situ state on cyclic performance Nerlerk case history Assessing the characteristic state of sands Summary Static liquefaction and post-liquefaction strength Introduction Data from laboratory experiments Trends in laboratory data for su and sr Nature of static liquefaction Undrained NorSand Understanding from NorSand Plane strain versus triaxial conditions Steady-state approach to liquefaction Trends from full-scale experience Lower San Fernando Dam revisited How dense is dense enough? Post-liquefaction residual strength Liquefaction assessment for silts Summary Cyclic stress-induced liquefaction (cyclic mobility and softening) Introduction Experimental data Trends in cyclic simple shear behaviour Berkeley school approach State parameter view of the Berkeley approach Theoretical framework for cyclic loading Dealing with soil fabric in situ Summary Finite element modelling of soil liquefaction Introduction Open-source finite element software Software verification Slope liquefaction Commentary Practical implementation of critical state approach Overview Scope of field investigations and laboratory testing Deriving soil properties from laboratory tests Laboratory measurement of cyclic strength Determining soil state by CPT soundings Application to typical problems in sands and silts Concluding remarks Model uncertainty and soil variability State as a geological principle In situ state determination Laboratory strength tests on undisturbed samples Soil plasticity and fabric Relationship to current practice What next? Do download ! A: Stress and strain measures B: Laboratory testing to determine the critical state of sands C: NorSand derivations D: Numerical implementation of NorSand E: Calibration chamber test data F: Some case histories involving liquefaction flow failure G: Seismic liquefaction case histories H: CamClay as a special case of NorSand References