Anisotropic strength criteria of sand: Stress-induced anisotropy

Stress-induced anisotropic strength of sand is analyzed on the particle level based on the micromechanics of granular. The differences between the isotropic strength and the stress-induced anisotropic strength are discussed from the viewpoint of micro-mechanism. Three classical strength theories, namely, M-C, M-N, L-D criteria, are discussed from the aspect of stress-induced anisotropy. Based on different anisotropies developed under triaxial compression and triaxial tensile stress condition, a simple fabric-stress relationship is proposed considering the effect of intermediate principal stress. A micromechanics-based stress-induced anisotropy strength criterion is developed to simulate the macro-mechanical response of real sand considering the effect of density state. Finally, several sets of true triaxial tests are chosen to be compared with the predicted results from the proposed strength criterion. The numerical results indicate that the proposed strength criterion, whose parameters have clear physical meanings, presents an effective approach to analyze the induced anisotropic strength characteristics of sand from the microscopic mechanism.