Experimental and numerical investigation of the punch-through shear test for mode II fracture toughness determination in rock

•Three dimensional PFC was used to simulate the process of punch-through shear test.•9 confining pressures ranging from 0.1 to 80MPa were tested in numerical simulation.•Multiple methods were used to present special and temporal evolution of fractures. The punch through shear test is a laboratory test used to determine the shear fracture toughness KIIC in rock. In this paper, the punch-through shear test was simulated using a discrete element particle model, and the dependence of KIIC on loading velocity and confinement ranging from 0.1 to 80MPa was investigated. The numerical results of KIIC vs. confinement match very well with laboratory tests, and the development of complex shear fractures during the test are analyzed in terms of the formation and coalescence of tensile and shear micro-cracking at different confining stresses, and the use of numerical acoustic emission recording.