Seismic Vulnerability Analysis Of Metro Station Structure Based On Pushover Method

The current seismic design of underground structures is limited to the concept of force-bearing structural bearing capacity.Under the action of strong earthquakes,only the structure does not collapse,but the degree of damage to the structure is not effectively controlled.The economic losses caused by strong earthquakes often exceed Tolerance range.Nowadays,performance-based seismic design methods are more and more accepted by scholars.The vulnerability analysis of structures is used to evaluate the seismic performance of new building structures and existing engineering structures,and to mitigate the damage caused by post-earthquake structures.The structure proposes rationalization and restoration suggestions have great guiding significance and deserves in-depth study.At present,the application of dynamic time history analysis method for seismic analysis of underground structures is widely used,but this method has a large computational workload and a complicated process.Pushover underground structure analysis method is a simple and accurate static calculation method.Based on the existing research literature,this paper studies the vulnerability analysis method of underground station structure based on Pushover method.The main research work is as follows:(1)Using the load-displacement hybrid loading mode,using the self-made fiber model-based steel and concrete constitutive subroutine,the Pushover analysis method of the underground station structure is improved,and the internal force of the underground station structure after entering the plastic stage is analyzed.Deformation laws,as well as damage characteristics.In the station structure,the joint between the column and the bottom plate enters the plastic stage first,which belongs to the weak part,and the first damage occurs.The bottom part of the side wall bears a large bending moment,and then plastic damage occurs.(2)Elastic-plastic dynamic time-history analysis of underground station structure,using Python script to quickly apply viscoelastic artificial boundary in ABAQUS software,study the damage law and weak position of underground station structure under dynamic action,and the weak position also appears in The center pillar is connected to the bottom plate.The accuracy of the improved Pushover analysis method is verified by comparing with the calculated results of the improved Pushover analysis method.(3)Based on the existing research results,norms and numerical simulation results,the failure modes of the underground station structure are summarized,and the inter-layer displacement angle is used as the structural seismic performance index to classify the seismic performance level of the underground station structure.By comparing the working conditions of different engineering structures,a reasonable quantitative index of seismic performance of underground station structures is proposed.(4)Using the improved Pushover analysis method of underground station structure,using the proposed quantitative index of underground station structure performance,describing the vulnerability of the structure in the form of vulnerability curve,establishing the vulnerability curve of the underground station structure,and proposing A method for analyzing the vulnerability of underground station structures based on Pushover method.In order to analyze the damage probability of the underground station structure under different earthquake strengths,it provides a basis for guiding the seismic design and post-earthquake repair of the structure.