Hierarchy of failure indicators in the failure analysis of geomaterials

Abstract

The failure of geomaterials presents distinctive features that arise from material response being dependent on pressure, density and fabric. In conventional plasticity, these dependencies are described by a non-associated plastic flow rule which provides mathematical sources for material or constitutive instability, thereby admitting a multiplicity of material responses for the same initial loading history. The non-symmetry of the tangent constitutive matrix due to non-associated plasticity triggers different failure indicators during material response history, leading to various failure modes such as diffuse or localized. The genesis of failure is analysed in a finite element computation of a drained compression test on sand in plane strain as a boundary value problem.