Dynamic Response Analysis And Parametric Study Of Subway Station Under Earthquake

Underground structure is an important lifeline of modern society,of which the subway station as an important part of the underground structure,has become an important transportation channel for people’s work and life,but at the same time of building the subway station,researchers also realize that the weak links of the subway station can be damaged under the action of strong earthquakes,affecting the safety of the entire station structure,so it is particularly important to study the seismic response of the subway station.Therefore,based on the Shaanxi public welfare geological survey project "Study on the Influence of Active faults and Strong Earthquakes on the Underground Space development of Xi ’an City and its prevention and Control Measures(Shaanxi Public Welfare Geology Special Project No.202109)",this paper takes a subway station in Xi ’an as the engineering background,and uses shaking table test and numerical simulation to analyze the seismic response and parameter influence of the subway station.The research contents and achievements of this paper are as follows:(1)This paper summarizes the seismic research status of underground structure of subway at home and abroad and the influence of soil-structure dynamic interaction,introduces the basic theory and damping theory in the dynamic finite element analysis of soil-underground structure,discusses the contact simulation of station structure and soil mass,and puts forward the research content and research methods of this paper.(2)The model structure was designed with a similar ratio,three different seismic waves were selected,and the vibration table test of the model system under the action of horizontal seismic waves was carried out,and the seismic response law of subway station was obtained.The results show that under the action of El-Centro waves,which have more developed lowfrequency components,the earthquake response of subway stations is more violent.Under different earthquakes,the top of the second layer of the middle column,the bottom of the first layer of the column and the roof plate are the weak parts of the earthquake,and the research results can provide a basis for the seismic analysis of subway stations.(3)Based on ABAQUS finite element analysis software,a two-dimensional numerical model was established,and the two-dimensional model was verified to reliably simulate the soil-structure dynamic interaction,and on this basis,a prototype two-dimensional numerical model was established to study the seismic response law of subway stations.The results show that the presence of underground structure amplifies the acceleration response of the surrounding foundation surface.The bottom of the middle column,the top of the middle column,the connection between the side wall and the floor,and the connection between the middle column and the floor are prone to large stress and strain values,and with the enhancement of ground motion,the stress and strain values gradually increase.With the enhancement of ground motion,the horizontal relative displacement of the structure becomes larger,and the difference in the horizontal relative displacement under different seismic actions is small,and the overall display gradually increases along the height,but the horizontal relative displacement along the height of the structure changes little.(4)Based on the prototype numerical simulation,the parametric analysis of the subway station was carried out,and the influence of the change of buried depth,structural size,soil Poisson’s ratio and soil elastic modulus on the seismic response of the subway station was considered.The results show that the peak ground acceleration values of the free field and the structural field gradually decrease with the increase of burial depth,and the soil-structure dynamic interaction is more significant,When the height of fill above the structure is small.The increase in buried depth deepens the relative horizontal displacement and stress response of subway stations.Increasing the width of the structure will increase the structural stress,but the effect on the relative horizontal displacement of the structure is minimal.Increasing the soil elastic modulus and Poisson’s ratio can effectively reduce the horizontal relative displacement and stress response of the top and bottom plates of subway stations.Based on the shaker test and numerical simulation analysis,the design suggestions of metro stations are proposed,and the research results can provide reference for the seismic design of metro stations.