Anisotropic strength criteria of sand: inherent anisotropy

Inherent anisotropy strength of sand is analyzed on the particle level based on the micromechanics of granular. An inherent anisotropic strength criterion is proposed, which will be reduced to the inherent anisotropy M-C criteria if the evolution of the initial fabric is not considered. The classical failure criteria such as M-N and L-D criteria can be extended to the inherent anisotropy strength criterion in this way and no extra model parameters are needed. In this sense, the proposed model is easy for engineering application. Based on a simple fabric-stress relationship considering the effect of intermediate principal stress, a micromechanics-based inherent anisotropy strength criterion is developed to simulate the macro-mechanical response of real sand considering the evolution of the initial fabric and the effect of density state. Finally, true triaxial tests are chosen to compare the predicted results with the proposed criteria. The numerical results indicate that the proposed strength criterion, which has rational mechanism, presents an effective approach to analyze the inherent anisotropic strength characteristics of sand.