Research On Seismic Response And Damping Technology Of Subway Station

With the acceleration of urbanization,the rail transit represented by the subway has developed rapidly.In the past,people thought that the subway station received the resistance of the stratum and had good seismic performance.However,in the Hanshin earthquake of 1995,the overturning damage of the big start-up station sounded the alarm for the seismic performance of the underground structure.At present,there is not a unified understanding of the earthquake damage mechanism of metro stations,nor a complete and effective theoretical system for the research on the disaster control technology of metro stations.In this paper,through theoretical research and numerical simulation,the impact of horizontal and vertical ground motions on metro stations is quantitatively analyzed,and the damping effect of the rubber bearing of the central column is studied,mainly including the following three aspects :(1)Based on the structural dynamics and elastic mechanics,the motion equation of subway station under the simple harmonic vertical vibration is established.When solving the internal force of the middle column,the mode function of the forced vibration of the roof beam is determined by using the Euler beam theory.According to the different constraint conditions of the column end to the roof beam,the corresponding vibration mode equation is solved,and the internal force of the middle column is finally determined.The vertical seismic effect on the middle column of the underground structure is relatively obvious,and the axial force caused by the vibration can reach twice of the static force,which will cause the damage of the middle column and affect the stability of the whole subway station.The mechanical principle of setting damping layer at the column end is to change the support condition of the roof beam from the fixed end constraint to the elastic constraint,which reduces the first-order frequency of the roof beam and reduces the impact of the roof beam on the middle column under the vertical earthquake;(2)The failure of subway station is caused by the incongruous deformation of the structure,among which the shear deformation resistance of the middle column is the key.Under the horizontal shear action,the tensile crack appears at the column end,which makes the vertical bearing capacity of this part of concrete reduce.As the crack penetrates the whole column end,the concrete at the column end is crushed,and the overlying earth gravity is transferred to the roof and side wall,the roof is bent,and in the middle of the span When the crack develops to a certain extent,the roof finally overturns due to the insufficient bearing capacity.Therefore,from the perspective of the failure process of the large start-up station,the failure of the center pillar is the main cause of the collapse of the station,and the shear deformation resistance of the center pillar becomes the key to improve the seismic performance of the station;(3)The damping mechanism of rubber bearing is to increase the ductility of the structure,improve the deformation adaptability of the middle column,transfer the interlayer displacement of the middle column to the support,the interlayer displacement angle of the middle column can be reduced by 78.8%,and the vertical bearing capacity of the middle column will not be reduced due to large deformation,so as to maintain the elastic resistance during the earthquake;by setting the damping support,the traditional fixed connection will be changed into "flexible" connection Through "flexible" decompression,the stress at the end of the column can be reduced,and the vertical stress at the end of the column can be reduced by 38.3%,so as to improve the seismic performance of the middle column.This thesis has 67 figures,18 tables and 127 references.