Study of the cylindrical wave propagation across a single rock joint with nonlinear normal deformation

Rock joints, usually with nonlinear deformation, widely exist in many natural rock masses, which greatly affect stress wave propagation. In practical engineering, the generated stress wave is taken as a cylindrical wave when an explosion with cylindrical charge or a tunneling explosion occurs. The cylindrical wave propagation in jointed rock mass is a great concern of underground structure safety. In this paper, the time-domain recursive method (TDRM) is extended to investigate cylindrical stress wave propagation through a rock joint with nonlinear normal deformation. Based on the conservation of momentum at the wave fronts and the displacement discontinuity method, a quantitative analysis for the interaction between wave and the joint is carried out and the wave propagation equation is accordingly deduced by considering the attenuation. Verification of the TDRM-based results is conducted by comparison with the simulated results from UDEC code. Finally, parametric studies are carried out, which include the influences of joint stiffness, the maximum allowable closure of joint and the frequency of the incident wave on the transmission and reflection coefficients.