Critical Plane Approach to Analysis of Failure Criteria for Anisotropic Geomaterials

Abstract

Numerous geomaterials such as rock and soil exhibit structural anisotropy related to material fabric elements such as crack pattern, bedding, layering, contact arrangements, among others. The fundamental problem is associated with the specification of effective properties of the representative material element, accounting for microstructure and defect distribution. The present work is aimed at the derivation of failure criteria for materials with anisotropic microstructure, such as crack pattern, microlaminate structure, or grain contact arrangement. The assumed density distribution function specifies the microstructure used in deriving the failure criteria and damage evolution rules for specified deformation histories. The state of a material is described by the damage density distribution on the physical planes. The critical plane approach is used with account for a damaged and an intact area fraction. The maximum of failure function is specified for all potential failure planes and critical plane orientation is determined. The derived failure condition is applied to study strength evolution for triaxially compressed specimens with varying orientation of principal stress and damage tensor axes. Also a general stress state is considered and the representative failure condition is derived. The application of failure criteria to particular cases is discussed. In particular, the limit states are specified for engineering problems, such as embedded anchor plate pull-out and rigid tool penetration into the material.