Abstract: According to a large number of findings on seismic hazards, the damages of tunnels during earthquakes depend on tunnel depth to a great extent. In order to study the effect of tunnel depth on lining, the earthquake responses of mountain tunnel in eight different depths are calculated by using the finite element method; and the seismic force loading method is verified, which confirms the rationality of the seismic load input method. In order to analyze the change of peak acceleration/displacement with increasing tunnel depth, the results of peak acceleration/displacement in both horizontal and vertical directions on key nodes of lining are extracted; and the influence of different tunnel depths on structural dynamic response is discussed. Some rules that the dynamic parameter peaks of lining decreased rapidly when the tunnel depth increases from 5 m to 50 m are found when calculating the ratio of peak acceleration/displacement on the section of different tunnel depths at vault. In addition, the influence of tunnel depth on peak internal force at tunnel vault is analyzed. And the comparative analysis between the results of the finite element calculation and the model test is made. Finally, the conclusion can be obtained that tunnel depth could not be less than 50 m when constructed in high-intensity earthquake zone, so as to provide reference for related projects.

Key words: tunnel depth, mountain tunnel, seismic response