A new nonlocal macro-micro-scale consistent damage model for layered rock mass

Abstract

Layered rock mass exhibits transverse isotropic characteristics in deformation and strength, and the strength anisotropy is difficult to achieve in traditional local action modes. Therefore, in the framework of nonlocal macro–micro-scale consistent damage (NMMD) theory, this paper constructed a micro damage criterion suitable for layered rock, where both the critical elongation and the brittleness index of material bond are defined as an elliptic function of the bond angle. Next, based on the geometric damage reflecting continuity loss of material point, which is obtained by the weighted average of bond damages around the point, an energy degradation model of a transversely isotropic stiffness matrix is established to achieve localized damage propagation of macroscopic cracks in the layered rock mass. The reliability and advantage of the NMMD model for transversely isotropic material are verified by comparison with the experimental and phase field results through a three-point bending shale beam with different bedding orientations. Finally, the splitting mechanism and bearing capacity of the Brazilian disk with different bedding directions and different inclinations of notch are explored through the established NMMD finite element model. The model is easily implemented, enabling automatic tracing of cracks and accurate prediction of load–displacement curves.