Seismic Response Analysis of Shield Tunnel Considering Mechanical Characteristics of Joints
|Course||Bridge and Tunnel Engineering|
|Keywords||Shield tunnel Joint models Segment internal force Seismic response analysis Dynamic finite element analysis|
Shield tunnel is a typical kind of prefabricated construction, in which theinfluence of joint on the entire ring of shields should not be ignored. The jointbetween segments is generally composed of gaskets and bolts, as a result, themechanical properties of the joint is closely related with the arrangement and materialproperties of the gaskets and bolts. In addition, the joint structure is not symmetricalalong the segment thickness, the gaskets are made from non-linear material, and thebolts need to be preloaded. These factors make the segment joint perform significantnonlinear characteristics when subjected to external loads, especially dynamic loads.However, the current dynamic analysis of tunnel rarely takes the joints intoconsideration, and the common joint model is too simple to reflect the mechanicalproperties of the joint. Therefore, the study on mechanical properties of joints andinfluence of joints on structure internal force during tunnel seismic analysis is verynecessary. Entity-nonlinear springs model of joint is developed according to thegeneral construction of the shield tunnel joint, and furthermore, combined withcommon homogeneous ring model and modified routine model, the influence ofvarious models on tunnel seismic response calculation is analyzed. The main work inthis article is described as follows:(1) Based on the general structure of the shield tunnel lining joints, themechanical properties of the joints is analyzed and the entity-nonlinear spring modelof joint is developed. And this joint model is applied in the finite element analysis ofthe whole ring tunnel lining structure by using finite element analysis softwareABAQUS.(2) With the example of Tianjin subway and three different kinds of model,including the model developed in this study, finite element analysis softwareABAQUS is adopted to analyze the transverse seismic response of shield tunnel. Bycomparing the internal force of segment with different joint model, the applicability ofdifferent joint models in tunnel dynamic analysis is studied.(3) Based on an engineering project, through the comparison of the calculationresults between whether to consider the joints, influence of joints on segment’sinternal force value and distribution is analyzed thoroughly. Combined with discussion on the traditional tunnel design ideas, suggestion on the future tunnelseismic response research and design is proposed.