Dynamic Response Analysis Of Subway Station Under Earthquake Load

The development of underground structures is relatively late,and the relevant experience and data in seismic design are far less abundant than those on the ground.Therefore,the seismic problem of underground structures has not attracted people’s attention for a long time.In recent decades,many high intensity earthquakes happened in the world,which caused serious damage to underground structures,and had aroused the attention of seismic engineers and seismologists at home and abroad on the seismic problems of underground structures.Based on the Qingdao Metro Line 1 Project,a three-dimensional finite element model was built on the large-scale finite element ANSYS platform.The Tianjin wave,Taft wave and El Centro wave were input to models for transient time history analysis respectively,and the general rule of the dynamic response of the subway structure under earthquake action was studied.The influence of enclosure structure and foundation grouting on the dynamic response of subway station was also studied.The main conclusions are as follows:(1)Because of the existence of the station,the stiffness distribution of the whole model is no longer presented in the horizontal layer distribution.Under the earthquake,the closer the same elevation from the station structure,the smaller the ground displacement amplitude;(2)The displacement response of the structure has obvious hysteresis phenomenon compared with the seismic acceleration.At the joint of column and plate,the stress concentrate at this position which caused by the rigid connection of column and plate.It should be emphasized in the design;(3)Under the same maximum acceleration,the response intensity of the subway station structure is close under the action of El Centro wave and Taft wave,which is much smaller than the response of the Tianjin wave,which indicates that the dynamic response of the structure is closely related to the selected seismic wave.When designing,we should combine with the concrete situation of the site and choose a variety of wave types to compare;(4)The dynamic response of subway station structure will be reduced by using enclosure structure,and the degree of reduction in different parts will be different.The top of the station will change greatly,and the bottom of the station will be smaller;(5)The ability of the structure to resist the dynamic load is improved after grouting,which indicates that the grouting can enhance the seismic performance of the structure to a certain extent.