MICROMECHANICS MODELING FOR STRESS-STRAIN BEHAVIOR OF GRANULAR SOILS .1. THEORY

Perceiving granular material as a collection of particles, a constitutive law for granular material is derived based on a micromechanics approach. The constitutive model takes into account the mechanisms of sliding and separation of particles under large deformation. One of the obstacles for modeling particle sliding is the nonuniform strain field under large deformation. In this paper we tackle this problem by introducing a distributive law that describes the heterogeneous strain field. A brief review of the previous work on granular mechanics is presented followed by a description of the current approach. This approach treats the material at three levels, namely, representative unit, microelement and interparticle contact. On this basis the constitutive laws for each level are derived, and the overall stress-strain relationship is expressed in terms of interparticle contact behavior. The unique features of the present theory are discussed to show its usefulness in comprehensive modeling of complex behavior for granular material.