A Review on Seismic Response and Aseismic Measures of Fault-crossing Tunnels

Several earthquakes have challenged the traditional view that the seismic performance of tunnels is excellent. The seismic damage of these tunnels has led scholars and engineers to study the seismic response of tunnels and underground facilities. Many earthquake damage investigations of mountain tunnels reveal that fault or fracture zone is one of the most critical factors leading to tunnel damage. In this paper, the mechanisms of seismic damages and the main factors that influencing the seismic response of fault-crossing tunnels have been explained. Based on two different aseismic philosophies, different aseismic measures of fault-crossing tunnels including buffer layer, fiber concrete, flexible joint, grouting and enlarging tunnel across have been review, and the advantages and disadvantages of different aseismic measures as well as their application scope have been assessed. The ideal aseismic design of fault-crossing tunnels is as follows: verify the fault activity, accurately estimate the possible displacement and the earthquake intensity of the fault area, and then combine the advantages of different aseismic measures, set up composite aseismic measures at the place where the tunnel crosses the fault zone. It is believed that the present study will help in a better understanding of the seismic response of fault-crossing tunnels and have some guidance of aseismic design of fault-crossing tunnels in engineering practice.