A nonlinear strength criterion for rock-like materials based on fracture mechanics

A nonlinear strength criterion for rock-like materials is developed in this paper. Taking a as an angle of micro-failure orientation in rock-like materials, a formulation between alpha and load is derived from a mixed-mode fracture criterion based on linear elastic fracture mechanics. According to micro-failure experimental phenomena of rock-like materials, a failure characteristic parameter under triaxial compression condition is chosen, which is relevant to con. ning pressure and is an invariant. A theoretical nonlinear strength criterion is also derived, which is exactly in the same mathematical form as the original Hoek-Brown empirical strength criterion. In addition, it is also found that the coefficient m in the Hoek-Brown criterion has physical meaning which is related to the ratio between the uniaxial compressive strength and the uniaxial tensile strength. (C) 2007 Elsevier Ltd. All rights reserved.