Study on the Dynamic Stability of an Underground Engineering Rock Mass with a Fault-Slip Seismic Source: Case Study of a URL Exploration Tunnel

Abstract

The application of fault-slip seismic sources is critical to the success of ground motion dynamic response analysis. Previous research established a finite seismic source to analyze stability in underground engineering. In this paper, a sophisticated numerical method based on the distinct element method (3DEC) is proposed to simulate the fault-slip seismic sources of an underground research laboratory (URL) exploration tunnel. Two indices, i.e., the peak ground velocity (PGV) and the strain energy density (SED), are used to analyze the sensitivity of the seismic source types, the seismic source radius, and the rupture velocities of the rock mass dynamic response. The simulation results indicate that a circular seismic source can be used so that the boundary produces a small singularity, with the seismic source having a remarkable influence on the PGV and SED. In addition, we consider that the rupture velocity is more suitable for engineering practices. A simulation method has been developed that allows the rock mass stability of a URL to be further explored.