A MULTILAIIINATE ELASTIC-PLASTIC MODEL FOR LIQUEFACTION OF SATURATED SAND

SUMMARY Modeling of liquefaction in saturated sand has been the aim of many resea-rchers to predict the mechanical behavior of soil under such conditions. The means by which pore water pressure accumulate due to cyclic loading has been studied using different usual tests and effective stress analysis has been proposed to simulate damages to structures due to liquefaction of surrounding soils. Although for the purposes of actual construction design the permanent deformation caused by an earthquake is a very crucial factor there is no verification study describing the permanent deformation caused by an earthquake. In this study, a meltnaminate based model capable of predicting the behavior of liquefiable sand under cyclic loading on the basis of sliding mechanisms and elastic behavior of particles has been presented. This ela-stic-plastic model is implemented in a finite element program to solve any boundary value problem. The capability of the model to predict the behavi-or of soil under undrained condition in the case of seeing the rotation of the principal stress axes, induced anisotropy due to plasticity has been examined. It is found that the proposed model can describe the behavior of sand under various cyclic stress paths conditions, and this model will be useful for actual liquefaction analysis. However, this model, based on effective stress analysis, is able to estimate pore water pressure accumu-lation, full liquefaction and final elastic-plastic deformation as failure sliding shear bands and settlements.