Two-phase model for nonlinear elasto-plastic behavior of reinforced soil structures using Pastor-Zienkiewicz-Chan model for matrix phase

The present study proposes a two-phase model to predict nonlinear elasto-plastic behavior, including deformation patterns and large displacements of geosynthetic-reinforced soil structures under monotonic loading. The two-phase model considers reinforced soil as the superposition of two mutually-interacting continuous phases; the matrix (soil) and the reinforcement (inclusion). The Pastor-Zienkiewicz-Chan model is implemented in a two-phase model as the constitutive law for the matrix phase by which the hardening-softening behavior of the two-phase medium can be considered. The model is applicable for granular soils under drained conditions. Inclusions are treated as linearly-elastic perfectly-plastic material. The perfect bonding hypothesis is assumed between the matrix and reinforcement phases. The approach was validated by comparison of the results with those of plane strain element testing and layered simulation models. Two centrifuge tests on geosynthetic-reinforced soil slopes were then simulated. The settlement, deformation pattern and potential failure surface of the slopes are also investigated. The results indicate satisfactory performance of the model for investigation of the nonlinear behavior of reinforced soil slopes.