Shear failure and mechanical behaviors of granite with discontinuous joints under dynamic disturbance: laboratory tests and numerical simulation

To investigate the fracture mechanical behavior and failure mechanism of jointed rock mass under compression and shear load. Conventional shear tests and shear tests under normal disturbances were conducted using an electro-hydraulic servo-motor loading system. Meanwhile, the discrete-element program particle flow code was adopted to establish a numerical shear model, and to discuss the microscopic deterioration characteristics and energy dissipation mechanism during shear fracture of rocks with discontinuous joints under joint action of normal static loads and dynamic disturbance. Compared with the conventional shear tests, shear test results under normal disturbances show the following specificities in terms of their macroscopic and microscopic mechanical properties as well as energy evolution: (1) frequent dynamic disturbances accelerate the non-steady fracture process of jointed rock samples and promote occurrence of the weakening effect of shear fracture. (2) The step-like abrupt increase in micro-cracks becomes more obvious before reaching the peak shear stress. (3) The energy-storage capacity and failure resistance of the rocks are weakened. The research results are of great significance for further understanding the dynamic catastrophe effect of deep rock mass.