Numerical evaluation of liquefaction-induced lateral spreading with an advanced plasticity model for liquefiable sand

Abstract Two different approaches are employed to predict the magnitude of lateral spreading induced by liquefaction using a two-dimensional finite difference analysis with an advanced plasticity constitutive model for the liquefiable sand. One approach uses the advanced plasticity model to directly predict lateral spreading. The other approach is a hybrid approach that first uses the advanced plasticity model to calculate the time to triggering of liquefaction and then uses a Newmark-type displacement analysis to predict the magnitude of lateral spreading. To evaluate the accuracy of these methods for predicting lateral spreading displacements, both approaches were applied to five well-documented case histories of lateral spreading. Comparison of the calculated and reported displacements shows that the hybrid approach that calculates lateral spreading with a Newmark analysis that employs the free field ground surface motions starting from the time at which liquefaction is triggered was, on the average, the most accurate approach. The two-dimensional finite difference analysis gave generally conservative results, yielding larger displacement than the reported value. While the uncertainty associated with both methods is very high, based upon the five case histories analyzed herein it appears that the two-dimensional finite difference analysis can be used with good confidence to predict a conservative value for the magnitude of liquefaction-induced lateral spreading if the parameters that govern lateral spreading are well known.