Seismic Time-History Analysis Of Subway Station Considering The Dynamic Contact Effect Of Soil-Structure

With the development of economy and the busyness of ground transportation,the construction scale of Chinese subway system continues to expand,and the seismic design of subway stations is increasingly concerned by engineers and technicians.However,the results achieved are still far from meeting the actual engineering needs.Therefore,it is necessary to study the seismic behavior of underground structures such as the subway station.Based on the theory of soil and underground structure interaction,ANSYS software is used to analyze the influence of dynamic contact effect on seismic response of the subway station in this paper.Then,taking a three-layer subway station in Xiamen as example,the displacement and stress responses of the metro station are analyzed.The main research contents and conclusions are as follows:Firstly,the key issues including material constitutive,boundary conditions,damping types and plane simplification methods in dynamical time-history analysis are discussed to determine the theoretical basis for modeling in this paper.Then,the finite element model of subway station considering the contact effect and not considering the contact effect are established respectively.Based on considering the dynamic separation and slip phenomena on contact surface,the effects of dynamic contact effect on interlayer displacements and structural stress of the subway station under different seismic waves are analyzed.The results show that:the displacement and stress responses of structure are significantly reduced when the dynamic contact effect is considered.In addition,dynamic contact effect has a greater effect on upper horizontal relative displacement than the bottom one.Then,the effect of earthquake and earthquake-trainloads are divided into six different conditions.Taking Xiamen metro station as example,the relative displacement between layers and stress of subway station under different conditions are analyzed.The results show that:when earthquake couples with train-loads,the displacement responses of structure are smaller than only the earthquake are considered.And there is an oppsite phenomenon in stress responses.Finally,the influence of boundary conditions,soil stiffness and structure stiffness on natural frequency,roof-floor relative displacement and structural stress response of Xiamen subway station under different seismic waves are studied.The results show that:Soil stiffness has the greatest impact on earthquake responses of structure.The increase of soil stiffness can decrease the displacement and stress responses availably.The earthquake responses using fixed boundary condition are greater than using viscoelastic artificial boundary.Furthermore,the structure stiffness should not be enhanced always since the increase of structure stiffness has tiny effect on dcreasing the earthquake of structure.