岩石压缩破坏强度的一种理论估值方法

There is still a challenge to reliably predict failure strengths of a rock subjected to complex loads by means of its experimental results under simple loading conditions. This work, based on the energy description of the mechanical model of Mohr-Coulomb criterion, suggests an approach to theoretically estimating the failure strength of the rock under complex compression from uniaxial compression test. It includes a critical energy condition for failure that is resulted from the energy conservation law between the elastic strain energy and the surface energy of crack at a point on the failure surface, and a failure criterion of the rock under polyaxial compression that is derived from the critical energy condition under the condition of constant shear modulus of elasticity and the volume change following a power law of the volumetric stress. Different from previously developed rock failure criteria, this criterion takes characteriscs of the rock deformation and cracking into account. Instead of being determined by fitting the test data of strengths, its three parameters are determined in calculation by using information of the uniaxial compression test. Applications show that the accuracy of its strength prediction may reach the same level as the best-fitting solution by using the Hoek-Brown empirical failure criterion.