Key Engineering Materials Vol. 627

Abstract: Direct shear tests conducted on the samples containing a central hole and prefabricated cracks are performed to make an analysis on the effects of the inclination angle, the number of prefabricated cracks and the normal stress on shearing characteristics. And the particle flow code in two dimensions (PFC^2D) based on discrete element is applied to carry on simulations on this tests. The micro mechanical parameters of the simulation models are determined by the calibration processes conducted on the shear stress-stain numerical curves of intact samples and the samples containing a pre-existing hole in both experimental tests and simulation tests. And then the micro mechanical parameters obtained above are applied in the simulation models containing prefabricated cracks with varying inclination angles and numbers. Based on the comparisons conducted on simulation curves and experimental curves, investigations of the initiation, propagation and coalescence mechanisms of the prefabricated cracks in both macro and micro scales are performed. And the results may shed lights on the failure mechanism of the surrounding rock involving holes and cracks.