Numerical Simulation of Meso-Mechanism of Liquefaction in Saturated Stratified Silty Sands

Abstract

Constant volume equivalent undrained testing is performed under cyclic loading by the PFC2D model, and the liquefaction behavior of saturated stratified silty sands is discussed from the viewpoint of meso-mechanism. Meso-scale parameters such as co-ordination number, distribution of contact normal and contact forces are studied under cyclic loading. Some results are obtained. The important factors which control the macro-response of saturated stratified silty sands are the average co-ordination number, distribution of contact normal and contact forces at meso-mechanical level. The major characteristics of deformation are stress-induced anisotropy and fabric-induced anisotropy. And the liquefaction behavior of loose saturated stratified silty sands is mainly due to continued and cumulative loss of the co-ordination number under cyclic loading. Numerical simulation can describe the liquefaction behavior of saturated stratified silty sands. The meso-fabric evolutions including co-ordination number, distribution of contact normal and contact forces can be analyzed during liquefaction induced by cyclic loading. Numerical simulation can also be used to illustrate and verify a theoretical relationship between measures of macro- and meso-scopic parameters that describe the anisotropy in contact forces and contact orientations.