Two-Phase Model for Nonlinear Dynamic Simulation of Reinforced Soil Walls Based on a Modified Pastor-Zienkiewicz-Chan Model for Granular Soil

Abstract

A two-phase model is introduced that simulates the nonlinear dynamic behavior of a reinforced soil wall, incorporating a generalized plasticity soil model and an elastic perfectly plastic inclusion model. The two-phase model is an extension of homogenization methods developed using the virtual work theorem. It considers composite reinforced soil as the superposition of two mutually interacting continuous phases; the matrix and the reinforcement. The main advantages of the two-phase method are that layer-by-layer modeling is not needed, modifying the arrangement of inclusions is easy, and computation time decreases considerably. The Pastor-Zienkiewicz-Chan model has been specifically modified to improve its prediction of the ratcheting effect during cyclic loading of geosynthetic reinforced soil walls and was implemented for the behavior of the matrix phase. The proposed approach uses finite-difference code and was validated using simulations of reduced-scale reinforced soil walls subjected to seismic loading in shaking tables. Lateral displacement of the wall face from the two-phase model was compared with experimental values at different acceleration amplitudes. Investigation of the deformation patterns and potential failure surfaces in the two-phase models shows overturning deformation mode and formation of a bilinear wedge-shape zone that is consistent with the results of experiments.