Research On Seismic Performance Of Subway Station Considering Soil-structure Interaction

With the large increase of population and the saturation of overground structural space,traffic congestion is inevitable.Underground rail transit has gradually become an important mode of urban transportation,and more and more cities begin to plan subway construction.For a long time,it is generally believed that underground structures have better seismic performance under the protection of soil.However,the seismic performance analysis that ignores soilstructure interaction will bring hidden danger to underground structures under strong earthquakes Therefore,this paper relies on the public welfare geological survey project of Shaanxi Province "Research on the Utilization of Urban Underground Space under the geological environment of High intensity disaster in Xi ’an(2021SF2-02)",and takes Xi ’an Aerospace City Subway Station as the background,designs and carries out shaking table test of subway station,and conducts three-dimensional numerical modeling analysis to explore the seismic performance of subway station under soil-structure interaction.The main research contents and achievements are as follows:(1)Based on the Buckingham π theorem,the scale model of subway station is fabricated,and four seismic waves are selected to carry out shaking table test of subway station under various working conditions.The seismic damage results and dynamic response are analyzed,and the dynamic response rules of subway station under different intensities and different frequency spectrum of ground motions are obtained.The results show that the damage degree is the highest at the top and bottom of the column in the subway station structure,and the dynamic response of the soil and the structure has an amplification effect along the height direction,and the dynamic response is obviously different under the ground motion of different spectrum.(2)ABAQUS finite element analysis software is used to carry out three-dimensional numerical modeling of subway stations and soil.The establishment of viscoelastic boundary and the transformation of equivalent node force is completed with the assistance of MATLAB programming software,and the effectiveness of the method is verified by a simple model.The results of numerical simulation and experiment are compared,and the two fit well,which verifies the effectiveness of numerical simulation.By using this model,the acceleration response and displacement response of soil-structure interaction system under different intensity and spectrum of ground motion are investigated,and the interaction law of soil and structure is obtained.The internal force response,stress response,deformation law and damage condition of the structure are analyzed,and the seismic weak parts and earthquake response law of the subway station structure are obtained.(3)By changing elastic modulus and density of soil and structure,variable parameter analysis is carried out to investigate the variation of soil-structure stiffness ratio and the influence of inertia effect on seismic performance of underground structures.The results show that: the ground motion response of underground structure is mainly affected by the surrounding soil mass.The stiffness and inertia of soil mass have great influence on the structure,in particular,the displacement response of the system has changed obviously,but the stiffness and inertia effect of the structure has little influence.