Anisotropic failure criterion for soils based on equivalent stress tensor

Abstract

Experimental evidence shows that both the inherent anisotropy and the loading direction have a considerable influence on the failure of geomaterials. Based on a micro-macro analysis of soil skeletons, the equivalent stress tensor is extracted from the equilibrium equation to measure the joint effect of the fabric tensor and the stress tensor. Using the equivalent stress tensor, an anisotropic failure criterion is proposed which combines the magnitude and the direction of the effective stress together with the microscopic characteristics of anisotropy. With the parameters determined by conventional laboratory tests, the predicted results are compared with the experimental results using various stress paths obtained from the literature. The results show that the anisotropic failure criterion is reliable and accurate for both true triaxial tests and torsional shear tests. Finally, the possible applications of the equivalent stress and the improvements necessary for the anisotropic failure criterion are discussed.