Seismic Elasto-plastic Analysis Of Subway Station Structure

With the accelerating process of urbanization,China's subway construction is in a stage of rapid development.Metro projects,especially subway stations,have become an important part of urban lifeline engineering.Protected by soil,subway station structures have better seismic performance compared with ground structures.However,multiple earthquake damages indicate that the structures of the subway station under earthquake may be seriously damaged and put people's life and property safety at risk.In recent years,the structures of subway stations have become increasingly complex and their scale has become increasingly large.It is of great significance to conduct in-depth seismic research on large-scale and complex subway station structures with special sections.For this reason,this paper conducts research on seismic elastoplastic analysis of subway station structures and the following work has been completed:(1)Theoretical analysis of the viscous boundary and viscoelastic boundary was carried out,and a numerical analysis model was established based on ABAQUS to compare the energy absorption effects of the different artificial boundaries under 2D and 3D conditions.At the same time,a ground motion input method corresponding to the viscoelastic artificial boundary was deduced,the ground motion data was converted into the time-history force applied on the boundary nodes of the finite elements,and the accuracy of the ground motion input method based on the viscoelastic boundary was analyzed by the finite element analysis.(2)Based on the ABAQUS subroutine,the secondary development of the uniaxial constitutive model of steel bars and concrete was carried out and compared with the test results.At the same time,taking the project of a subway station structure with the atrium roof which has an opening hole in Suzhou as an example,the elastoplastic modeling method based on fiber-column model and soil-structure interaction is studied in detail.(3)Based on the benchmark calculations,two-dimensional soil-structure interactions of four fracture types(without opening hole,3.8m opening hole on the sides of the roof,2m opening hole on the sides of the roof,and 3.8m opening hole in the atrium)were established.The finite element model,through twodimensional elastoplastic time-history analysis,studies the influence of key parameters,such as with or without opening hole,size of the opening hole,and position of the opening hole,on the seismic response of the main structure.(4)A three-dimensional soil-structure interaction model of a subway station structure with an atrium roof which has an opening hole was established.The time-history analysis was performed using artificial waves of three levels of strength and the results were compared with two-dimensional model at the corresponding location to investigate the difference between the calculation results of the 2D model and the 3D model.At the same time,considering the large amount of calculations for the 3D elasto-plastic time-history analysis of the underground station structure,the elastoplastic pushover analysis of the 3D soilstructure interaction model was studied and time-history analysis results were compared and verified;(5)To solve the problem that seismic sectional analysis in “Code for seismic design of urban rail transit structures” is difficult to apply on the of large-scale and complex underground structures,the underground complex of Wuhan Guanggu Subway Station was used as the engineering background to establish the threedimensional elastoplastic finite element model of the extremely large-scale and complex subway station structures.The three-dimensional elastoplastic pushover analysis considering the soil-structure interaction and the elastoplastic time history analysis of the load-structure model with soil spring were carried out to provide a practical method for the seismic evaluation of large-scale and complex subway station structures.