Numerical study on oblique incidence across rock masses with linear and nonlinear joints

The two-dimensional discrete element program Universal Distinct Element Code (UDEC) is applied to simulate stress wave propagation across linear and nonlinear rock joints with arbitrary incident angles. The numerical study for stress wave obliquely impinging upon a single linearly elastic joint is firstly conducted. For this case, the wave-type transformation is analyzed and the variations of transmission and reflection coefficients with joint stiffness and incident angle are investigated numerically. It is found that numerical results agree well with those from existing theoretical methods, which demonstrates the feasibility of using UDEC to simulate the propagation of obliquely incident stress wave across a single joint. Furthermore, the transmission of obliquely incident waves across a set of parallel joints is investigated and compared with analytical solutions when the joints are linearly and nonlinearly elastic, respectively. The numerical results indicate that the parameters, such as the joint number, the joint spacing and the mechanical property of joints, have great influence on wave propagation through joints. The results in the present study may provide a reference for revealing stress wave propagation across jointed rock masses and the responses of rock masses subjected to dynamic loads.