Longitudinal Seismic Response Analysis Of Shield And Excavation Tunnel Based On Response Deformation Method

With the development of society and the increase of city population, the city traffic has overwhelmed. Traffic congestion has become a common problem of the big city, people gradually realize the importance of the development of underground traffic engineering construction in the city. Because most of our country is an earthquake prone area, so it has an important social and economic significance to ensure the seismic safety of underground traffic engineering. This article is based on one underground tunnel engineering of the Tokyo to analyze its longitudinal seismic response using the displacement response method. The main work is as follows:(1)Take the project of a underground traffic tunnel line A as an example, adopt the nonlinear dynamic analysis software TDAPIII to build the model based on the response displacement method. The beam element is used to simulate the tunnel structure and the connected spring is used to simulate the connection between segmented connection box in excavation tunnel; The beam element is used to simulate the duct piece and the connected spring is used to simulate the joint bolt in shield tunnel; The spring is used to simulate the interaction between soil and structure. All these contribute to establish a finite element model of tunnel, a series of seismic response of the tunnel structure can be obtained through the analysis of finite element.(2)Make the analysis of the result of the seismic response of tunnel structure, including the internal force of tunnel and the deformation reaction between the box body in excavation tunnel; The internal force and the deformation reaction between joint bolt in shield tunnel and so on. The stress characteristics of the tunnel structure under earthquake can be understood and the evaluation of tunnel structure will be given according to the relevant code for seismic design. In the end, some appropriate optimization design can be used in the seismic weak parts.Through the research of this paper, These conclusions are concluded as follows: Dynamic time history analysis based on the response displacement method and finite element modeling method has a good practicability in tunnel seismic design. The integrity and seismic performance of the tunnel structure is contradictory. If the structure is divided into several sections and appropriate connection is used between the sections, it will effectively improve the seismic performance of the structure. Because of the different size of the structure box in the junction of different lines of tunnel, the axis in the structure will have a mutation and additional bending moment will result according to the eccentric force, this can lead the structure to collapse. The joint of shield tunnel and shaft is easy to get concentrate affection of the earthquake because of the change of structural stiffness, this can lead to local force or deformation gauge. As the buried depth of the tunnel get bigger, the stress and deformation of structure decreases gradually. In addition, the structure is prone to damage in the geological characteristics of sudden change.