Study On Seismic Vulnerability Of Two-Story And Three-Span Subway Station

In order to alleviate the shortage of land resources and traffic congestion,the development process of urban underground space projects is further accelerated,with the development of urban construction and the increase in the number of urban populations.Metro station structure is a crucial part of underground rail transit engineering.Once severe earthquake damage occurs,it will not only be difficult to repair the subway station,but will also cause huge economic losses and casualties.Therefore,it is of great significant to simulate the damage of subway station structure based on earthquakes of different intensities.Studying the vulnerability of underground structures provides a reference for earthquake damage prediction and seismic loss assessment of underground structures.In this study,an overall finite element model of the site soil-underground structure coupling is constructed using a typical two-story three-span subway station structure as an example.Combining with the IDA method,the nonlinear dynamic response of the model is calculated and an analysis of the damage state of the structure is calculated.Then,the structural vulnerability curves are obtained via the method of probability statistics.The main work of this paper is as follows:1.By summarizing the historical seismic damage data of underground structures,the forms and characteristics of earthquake damages of common underground structures are clarified.Next,combined with the existing study results of seismic response of underground structures,I analyze the earthquake damage mechanism of underground structures.Then,according to the damage process of reinforced concrete members,the failure criteria of subway station structures are given.Finally,with reference to the existing classification methods of seismic damage grade of building structures,a method for dividing the seismic damage grade of subway station structure based on component damage is given.2.The seismic response analysis of the subway station structure is carried out using IDA method.Taking the concrete compressive damage factors of structural members and the tensile stress of steel bars as performance parameters,the corresponding relationship between performance parameters and the grade damage of structural members is given.Based on the quantitative suggestions for the damage grade classification of the subway station structure,the damage of the subway station structure under different seismic waves is analyzed.3.The statistical results of the earthquake damage of the subway station structure are obtained through IDA method.With the reference to statistical methods and the theory foundation of structural vulnerability analysis,the probability of the subway station structure reaching different failure states under the action of different intensities of earthquakes is calculated.The impact of seismic waves obtained under similar site conditions as ground motion input on the vulnerability of subway station structures is estimated.