Analysis Of Seismic Response And Failure Mechanisms Of Subway Station

In the recent years, with the development of our nation's economy and the rapid increase of the citizen, the underground structures develop rapidly, more and more complex and large cross-section underground structures appear in many places of our country. Before, people generally thought the anti-seismic ability of underground structures is very good due to the information of the damage to underground structures from earthquake is few, the research of underground structure anti-seismic is few, but the underground structures were damaged badly in the KOBE earthquake, especially DAKAI subway station collapsed completely and lost the function of use, which made above main way collapse, the most settlement was more 2.5m, which affected the succor. The economy loss brought by underground structures in the KOBE earthquake is approximately 300 hundred million yen. Henceforth, there happened many earthquakes resulting in damage on underground structures. In our country, the research on underground structure anti-seismic is few. Now, we have not uniform underground structure anti-seismic design criterion. therefore, this article researches the destroy mechanism of underground structure by the finite element method and the DAKAI station serve as the main research object.The article firstly analyses the seismic response of DAKAI station's surrounding ground by the one dimension equivalent linearization program SHAKE91, we obtain the equivalent damp and equivalent shear modulus by computing. The two dimensions plan stain finite element model is established in this article, according to factual structure size and ground information. The non-linearity of material and member for RC structure is considered by fibre element model, the ground dynamical non-linearity is considered by equivalent damp and equivalent shear modulus. The input earthquake is the vertical and south-north acceleration waveform obtained on rock of -83m depth in Port Island. The destroy mechanism of DAKAI station is obtained by analyzing the structure internal force,relative displacement,the destroy status of fibre element sections and the earthquake characteristic. The RC structure non-linearity is very important in underground structure anti-seismic research by analyzing the results of elastic model and plastic model. The destroy effect of the vertical earthquake to RC underground structure is analyzed by the formula of shear force limiting design value and the mutual effect curve of normal force and bending moment. The influence of ground stiffness on seismic response is analyzed, at the same time, we know that the influence of the ground dynamic non-linearity on underground structure seismic damage is prominent. The column are the most weak part in underground structure, we analyze the bending failure, shear failure and normal pressure failure of the column. We understand the seismic damage process of the column deeply.