A micromechanically-based approach to failure strength for anisotropic geomaterials

The paper aims to propose a macroscopical failure criterion of anisotropic geomaterials based on micromechanical analysis. The study deduces the formulations of overall stress at the microscopical scale. The anisotropy is assumed as the result of the materials fabric, which is described using the second-order density function of particle branch vector. The failure strength is defined in terms of the particle fabric and contact force. The proposed failure criterion implies that the friction strength depends largely on the inclination of major principal stress with respect to the bedding plane, partially on the interparticle friction. The maximum strength is always available when major principal stress is applied in the direction normal to bedding plane. The minimum friction strength tends to appear on the bedding plane.