Prediction of geomechanical changes in faulted rock mass around underground structures subjected to earthquakes

Abstract

Faults are a type of geological structure that often leads to geological disasters in underground structures under normal conditions and especially when earthquakes occur, thereby requiring careful study. This article introduces some numerical simulation results on the seismic wave propagation process, on changes in stress and displacement states in the rock mass with a small fault of a dip angle of 45^o, around a circular cross-section tunnel, using the discrete element method (Universal distinct element Code - UDEC). Three cases are simulated: a) The tunnel is located in the hanging wall rock, the fault is located 10m from the centre of the tunnel on the vertical axis; b) The fault runs through the centre of the tunnel and c) The tunnel is located in the footing wall rock, the fault is located 10m from the centre of the tunnel on the vertical axis. The results obtained show a very clear influence of the position and location of the fault on the geomechanical changes in the rock mass around the tunnel, contributing to the reasonable design of tunnels subjected to earthquakes.