Abstract:The crack isolating theory combined with internal variable theory including a micro-to-macro transition is applied to study the localization of deformation and the complete stress-strain relation for intermittent crack-weakened rock masses under compressive stresses. The self-similar model is selected as a basic dissipative mechanism underlying macroscopic inelastic deformation. The closed-form explicit expression for the complete stress-strain relation of rock mass is obtained. The complete stress-strain relation includes the stages of linear elasticity,non-linear hardening,and strain softening. The results show that the complete stress-strain relation and the strength of rock mass depend on the crack interface friction coefficient,the crack spacing,the perpendicular distance between the two adjacent rows,the fracture toughness of rock material,and the orientation of the cracks. Special attention is paid to the transition from distribution damage to localization of damage and the transition from homogeneous deformation to localization of deformation. Theoretical predictions are consistent with the experimental results.