A failure criterion for anisotropic soils

Soil in nature is usually anisotropic,but most of the classical failure criteria can only take isotropic behaviors into account. A modified deviatoric stress tensor is defined,combining the stress tensor and the fabric tensor describing the characteristics of anisotropic materials. Based on the invariants of the modified deviatoric stress tensor,a failure criterion for anisotropic soils is proposed. Failure surfaces in the general stress space for the anisotropic and cross-anisotropic materials under coaxial conditions,as described by the criterion,and the relationships between the coefficient of intermediate principal stress b and friction angle in different sectors are presented. Their characteristics are analyzed and compared with those for isotropic materials. By comparing with the experimental data from true triaxial tests,the capability of the criterion in modeling the failure of anisotropic material is demonstrated.