Earthquake Analysis Of Subway Tunnel And The Initial Search About Interface Of Soil And Structure

With the rapid development of China's economic and expansion of cities, development of underground space has become a major problem for solve urban traffic. How to understand the seismic response of subway tunnels and given the safety evaluation for underground structure has become a very important problem. This paper summarizes the status of seismic analysis of underground structures and soil-structure interface research issues, Finite difference program FLAC software has been used to simulation the .seismic response subway tunnel. The contact surface of soil and structure issues are also been studied. Contents are as follows:1. Finite difference method and the application of principleThe FLAC program has been studied for calculation and an elabotation on how the Mohr - Coulomb model used in the program are given in this paper. As the boundary treatment selection, A finite difference method has been used in a case for the selection of different artificial boundary effects on the numerical simulation results to determine the seismic response analysis of the input method of scattering field.2. Seismic Response of Round Shape TunnelLinear and non-linear seismic response analyses have been done for round shape tunnel without considering the separating and slipping between soil and tunnel lining. The simulation results show that: The maximum dynamic axial force locates in the lower part of the tunnel. the maxium dynamic moment locates in the direction which has an angle of 45°from the vertical symmetrical axis; The maxium of dynamic shear force locates in the two ends of the vertical symmetrical axis.3. Interface element principle of soil and structure and their influence to circular tunnel dynamic response. The interface element principle and the application method has been studied, and the analysis of earthquake response between soil and the tunnel liner at apply the interface element or not has been contrasted. This paper gave the change law of tunnel liner dynamic internal force extrema. The change law of relative displacement distribution of soil and tunnel liner along the cycle also been discussed.4. Dynamic response of site conditions and shape on tunnelThe effect of relative displacement, caused by one ground motion, between upper and bottom of the circular tunnel which embed in different soil and different depth has been studied. Meantime, compare the seismic response on different shape (rectangular and horseshoe-shaped) tunnels at the same site condition. Present the distribution regular on extreme value of internal force compare with the circular tunnel. discussed seismic response differ in different tunnel'shape.