Abstract:

A 3D seismic analysis model of Taihu quasirectangular tunnel is established based on large mass method, so as to the variation rules of internal force and displacement rules of the tunnel structure under the action of horizontal seism. The study shows that: 1) The structural internal force in sidewall bottom is the largest under the horizontal seismic action; and the bending moment plays the main control force. 2) Transition section No. 1 and 2 are the weak points of the tunnel under the seismic action; and the maximum internal force is located in transition section No. 1. 3) The story drift angle increases from the shallowburied section to the deepburied one; and the maximum story drift angle is less than the standard limit. The results can provide references for seismic design of Taihu Tunnel.

Key words: large mass method, 3D model, seismic response, quasirectangular tunnel