ABSTRACT
A micro-mechanics-based model is developed to investigate microcrack damage mechanism at the stages of rapid stress drop and strain softening of brittle rock under rotation of the principal stress axes. The frictional sliding crack model is applied to analyze microcracks nucleation and propagation. Effects of rotation of the principal stress axes on microcracks nucleation and propagation and coalescence, as well as the inelastic strain increments and shear deformation localization of brittle rock, are investigated. It is shown that the dynamic damage constitutive relationship and the failure strength of brittle rock are sensitive to rotation of the principal stress axes.
