Study On Dynamic Characteristics And Risk Of Cross-Span Frame Subway Station Structure Under Earthquake Action

With the development of cities in China,the subway has become an important part of people’s travel mode.With the combination of the subway and the underground complex,a kind of cross-span subway station with wide in the upper part and narrow in the lower part appears in people’s sight and gradually becomes the mainstream selection of subway stations.However,the seismic dynamic response of subsurface structures with such complex sections is rare,and whether it can adapt to complex sites needs to be further verified.Therefore,this paper uses MIDAS-GTS finite element analysis software to analyze the seismic dynamic response,influence factors and seismic vulnerability of the underground station structure.The main research contents of this paper are as follows:This paper arranges and analyzes the basic theories and key problems of the subway station structure,and seeks for a reasonable calculation method to guarantee the correctness of the finite element software analysis results.We determine the basic assumptions,artificial boundary conditions,constitutive relation,seismic wave selection criteria,input and adjustment method,and the selection of influence parameters of the subway station model.(2)Through MIDAS-GTS,the three-dimensional numerical model of the underground subway station was established.With the maximum internal force of each component and the displacement Angle of the top and the floor plate as the evaluation indexes,three different ground shocks were selected to analyze the seismic dynamic response of the subway station structure.By comparing the displacement Angle of three different beams,the dynamic characteristics of ring beams are explored and compared.(3)By changing the location of the soft soil interlayer around the subway,analyze the influence of the parameters of the clay layer,including elastic modulus,cohesion,Poisson’s ratio and friction angle,for the sensitivity analysis of the subway station structure.(4)The maximum displacement Angle was selected as the parameter basis for dividing the damage grade of the station structure,and the incremental dynamic analysis(IDA analysis)was conducted on the station structure under 10 different ground shocks.At the same time,the regression equation of the station structure is drawn.On this basis,the seismic vulnerability curve of the station structure is solved,with the result of analysis.