Investigation of stress wave induced cracking behavior of underground rock mass by the numerical manifold method

Abstract

The present study investigated the coupling effects of cracking and wave propagation on the underground rock mass by the numerical manifold method (NMM). The traditional NMM was developed for the simulation of dynamic cracking behavior of rock mass. One-dimensional wave propagation was utilized to validate the present code. Subsequently, the transient stress field in the rock mass with an inclined crack was investigated. Finally, two cases of underground caverns with symmetrical or unsymmetrical discontinuities under stress wave were simulated to validate the application potentials. The results show that the transient stress field is not only influenced by the stress concentration around the pre-existing crack, but also influenced by the characteristics of stress wave, e.g. reflection, transmission and diffraction, which are different from the static situation. The results also show that the cracking significantly affects the stress wave duration and amplitude. On the other hand, the stress wave induced cracking depends on the wave propagation distance significantly. Moreover, the NMM can be used to simulate the cracking behavior of underground rock mass under stress wave efficiently.