Numerical Study of P-Waves Propagating across Deep Rock Masses Based on the Hoek–Brown Model

Abstract

Strong dynamic disturbances constitute an important problem threatening the safety of deep underground engineering projects. The mechanical mechanisms responsible for such disturbances in deep rock masses can be revealed by studying stress waves propagating across them. In this study, the propagation of P-waves across a deep rock mass was investigated both numerically and theoretically. The Hoek–Brown (HB) model, which is able to account for the stress state and nonlinear failure of the rock mass, was employed. In particular, the time-domain recursive method was extended to analyze the propagation of P-waves across the rock mass following the HB failure criterion. Good agreement is found between the theoretical results and simulations, which demonstrates that using the Universal Distinct Element Code (UDEC) with the HB model to study the transmission of P-waves across rock masses is eminently feasible. The effects of the disturbance factor, confining pressure, incident amplitude, and coupling of joints and rock mass quality on wave propagation were also studied using the UDEC in a systematic manner. The results show that for an incident P-wave of given amplitude, the greater the rock mass quality and smaller the disturbance factor, the greater the transmission coefficient. In addition, there is an upper limit to the effect the confining pressure has on the transmission coefficient. The amplitude of the incident wave also has an important influence on the transmission coefficient. Finally, if the quality of the rock mass is good and the disturbance slight, then the attenuation of the wave is primarily caused by the joints.