Strength and Failure Characteristics of Rocklike Material Containing a Large-Opening Crack under Uniaxial Compression: Experimental and Numerical Studies

A series of uniaxial compression experiments was conducted on rocklike specimens containing a large-opening crack to investigate the effect of inclination angle and length of crack on the uniaxial compressive strength (UCS) and failure mode. A particle flow code, based on the discrete element method, was used to simulate the propagation process and reveal the fracture mechanism of a preexisting crack with a large opening. The failure of these large-opening crack specimens was mainly caused by the development of shear secondary cracks and not by tensile wing cracks, although the shear cracks initiated from the crack tip after the tensile wing cracks. The preexisting large crack remained open after compression failure. The mean rupture angle was approximately 63.6°, and it was independent of the crack inclination angle and length. An increase in inclination angle from 0° to 90° or a decrease in crack length from 30 to 0 mm led to a nonlinear increase in UCS owing to the increase in effective shearing resistance area. The experimental results are in accordance with the numerical results, and they provide a significant understanding of the UCS and failure characteristics of rocks with large-opening cracks.