Abstract:
This paper investigates the initiation and growth criteria for compression-shear crack and provides theoretical analysis for former experience compression-shear fracture criterion. On the basis of compression-shear crack model, the compression-shear damage model for rock mass is proposed with crack closing effect and crack interacting. From the proposed model, it is found that rockburst results from macroscopic brittle fracture of rock mass due to frictional sliding, interface propagating, kinking, and linking of preexisting cracks in rock mass activated by stress redistributing (tangetial stress concentrating and radial stress relieving) of surrounding rock mass during (or after) excavating of underground carven. Numerical simulations indicate that the results from proposed models can simulate available experimental results very well and crack closing stress has a significant influence on the stress-strain relationship of rock mass. It is shown that the damage strains, especially the lateral strain, increase with the raise of the crack closing stress.