Study On Seismic Response Characteristics And Design Method Of Subway Station With Attached Ground Structure Or Sunken Plaza

Rail transit has become an important way for people to travel.Scholars at home and abroad have done a lot of research on the seismic theory and design method of fully buried underground structures.For large and complex underground structures appearing in recent years,their seismic theory,design method and failure mode have not been fully studied.This paper mainly discusses the seismic response characteristics and design methods of two subway stations with accessory ground structure or sinking square.Firstly,the theoretical rigor of the practical seismic design method is verified according to the structural characteristics;secondly,the seismic response analysis of the subway station with the attached ground structure is carried out,the applicability of different practical seismic design methods is compared and analyzed,and the influence of the above ground part on the seismic response of the underground structure is explored;thirdly,the seismic response of the subway station with the sunken plaza and practical seismic design method are considered.Finally,the elastic-plastic analysis of two kinds of subway station structures under earthquake action is carried out.The main results of this paper are as follows:(1)For the subway station structure with attached ground structure,two practical design methods of seismic design are selected,which are response displacement method and mode decomposition response spectrum method,and the theoretical rigor of response displacement method is verified.Referring to the actual engineering,five structural forms are established,and the applicable conditions of the two practical seismic design methods are obtained by comparative analysis the results of dynamic time history analysis.The internal forces and displacements of different structures are compared.The results show that the ground part has adverse effects on the underground part under the earthquake,and the higher the number of stories and the more spans of the ground part,the more unfavorable the underground structure is.(2)Considering the structure of subway station with sunken plaza,the dynamic time history analysis results show that the bottom of the side wall of the subsidence square,the intersection of the floor and the main body of the structure is the key position of the seismic design,and the floor of the square hardly needs to consider the seismic load;when calculating with quasi-static method,the non-horizontal braced component of the subsidence square belongs to the retaining wall,so the sunken plaza and the main structure need to be separated in the design.The calculation shows that the side wall of the sunken plaza is used as the retaining wall for seismic design,and the main structure is designed by the response displacement method.(3)Elasto-plastic dynamic time history analysis of the above two structures shows that the failure modes of similar structures are different from those of fully buried underground structures.With the increase of incident seismic wave intensity,plastic hinges appear first in the middle plate,then the middle column yields,and finally the plastic hinged structure tends to fail in the side wall;the greater the stiffness of the soil around the structure,the smaller the elastic interlayer displacement angle limit and the failure limit displacement angle of the structure;the elastic interlayer displacement angle limit calculated in this paper is obviously smaller than that stipulated in the code,which shows that for the two complex sections,the elastic interlayer displacement angle limit is obviously smaller than that stipulated in the The elastic displacement angle limit and plastic limit displacement angle of the lower structure can not be simply applied to the values prescribed in the code,and need to be further explored.