A Three Dimensional Plasticity Model for Sands Based on State Concept

Abstract

A three dimensional plasticity model for shear deformation in sand is developed based on the plane strain model of Cubrinovski and Ishihara [1]. The model uses a circular bounding surface. The model is hypoplastic in nature, rendering the principal directions of plastic strain increment different from those of the stress, and thus, allows for accumulation of plastic strain with principal stress rotation. The model uses the multi-surface based mixed hardening rule. This paper presents results from simulations under bi-directional (torsional-stress path) uniform stress cycles, as well as bi-directional stress-controlled simulation results, where two orthogonal horizontal components of a ground acceleration time series are converted to bi-directional stress history, providing a rigorous verification of the algorithm.