Evaluation model of circular tunnel lining subjected to dislocation earthquake point source in semi-infinite media

Abstract

Earthquakes are generated by fault dislocations, propagates outward in the form of seismic waves in the stratum, and cause the mechanical response of the tunnel lining. In this paper, an evaluation model of circular tunnel lining under the action of dislocation earthquake point source in semi-infinite space is proposed, which describes the effect of the earthquake point source on the tunnels. First, the tunnel-source coordinate system is defined, the Green function-based equation for the stress field due to dislocation source in a semi-infinite medium is derived, and the source time function is introduced. Then, based on the seismic stress state at the tunnel location, the stress response of the tunnel-ground system is derived, and a miniature dynamic finite element model is developed to verify the evaluation model. Compared with existing related research, this evaluation model consists of the dislocation earthquake source and the local tunnel system, instead of only focusing on local tunnel systems, which can take into account the spatial location of the earthquake source and the tunnel, the magnitude, and the type of earthquake. In addition, the parameters such as source fault type, epicenter distance, magnitude, earthquake rise time, and tunnel azimuth are also discussed. The evaluation model can analyze the response of the tunnel during an earthquake at a larger scale.