Analysis Of Anti-seismic Performance Of Mountain Tunnel In Earthquake Region

The anti-seismic performance of tunnel is being paid more and more attention to. Based on many seismic damage facts of tunnels all over the world, characteristics of seismic damages are summarized. Existing methods of anti-seismic analysis of underground structures are briefly reviewed, as well as current researches of anti-seismic performance of underground structures. In this thesis, anti-seismic performance of tunnel lining is studied.In the thesis, the general approach to establish the boundary conditions of dynamic analysis of underground structures is introduced. Especially the hypothesis and parameters of viscous boundary are discussed in detail. Considering that the parameters of the viscous boundary are changed along with the characteristic of the surrounding rock, while the free boundary is irrelative with it, numerical results of viscous boundary and free boundary are compared in different surrounding rock conditions, and the differences of numerical results of the both boundary conditions are analyzed. Base on that, the variation laws of differences of numerical results of both boundary conditions with the surrounding rock conditions are gained.Based on the data and other information of a tunnel in the Xiashen railway,2-D elastic-plastic finite element model is established. According to the numerical simulation analysis, the distribution laws of the internal forces of the tunnel lining are studied. During the process of analysis, the safety factor of the lining is taken as the judging standard of the structure response for evaluating the anti-seismic performance of tunnel. Parameters of tunnel lining, such as thickness, peak acceleration of the earthquake and buried depth, are discussed in detail. Finally, numerical simulation analysis is performed to study corresponding influencing laws of those parameters to anti-seismic performance of tunnel lining, and corresponding fitting formula is obtained. Based on these fitting formulas, the cooperative influencing law of all the parameters to anti-seismic performance of tunnel lining is obtained.Through this thesis researches, some beneficial rules and conclusions have been gained for boundary conditions of dynamic numerical simulation and anti-seismic performance of tunnel lining, which will provide valuable reference for design and construction of tunnel in mountain areas.