Study On The Influence Elements Of Seismic Dynamic Response Of Portal Of Mountain Tunnel

With the west of China greatly exploiting, a mass of tunnels for highway, railway, and water projects have been constructed. It is inevitable for tunnels to be constructed across active fault or in high earthquake intensity regions. The study on seismic response of underground structures is of great economic and social significance. At present, the forms and conditions of mountain tunnels are various, and the study on the law of the dynamic response of mountain tunnels under various conditions are not comprehensive and in-depth enough.In response to these problems, the mode and. the mechanism on earthquake damage of mountain tunnels in the history are studied, the response history analysis (RHA) method is applied in this paper, numerical simulation in dynamic response of three different form tunnels is performed, and the law of the dynamic response of portal of mountain tunnels are analyzed. The main contents of this paper are as follows:1. Through the collection of damage data and related conclusions of the theory, the mode and the mechanism of the damages in the earthquakes of mountain tunnels are summarized, and the general law of earthquake damage of tunnel is obtained.2. The numerical issues of dynamic history such as boundary conditions, damping model, the calculation of regional, discrete units are discussed3. Numerical simulations of three different cross-section tunnels in different conditions of the country rock and different buried depth are done, the law of the impact of the factors on the dynamic response of mountain tunnels is analyzed and summarized.4. Current antiseismic measure of runnels are analyzed and summarized, the characteristics and the roles of the methods are obtained, the appropriate and feasible measures to improve the safety of the tunnels in earthquakes are explored, with a view of the actual works reference.