| The subway station has the characteristics of space airtight and crowd gathering.The explosion inside not only directly endangers the personnel and equipment near the explosion source,but also causes vibration of the station structure,leading to the failure or damage of the structural components.In addition,the explosion shock wave transmitted to the ground through the soil will cause the ground vibration,which will threaten the safety of the subway station upper cover structure and the ground personnel.In this paper,LS-DYNA software is used to study the ground vibration and the dynamic response of the typical upper cover structure when the internal explosion occurs in the subway station.The main research contents are as follows:(1)Using LS-DYNA finite element software,the model of subway station surrounding soil is established to simulate the propagation and attenuation of explosion shock wave in soil.This paper analyzes the influence of different factors on the ground vibration,fits the ground vibration speed and acceleration under 60 working conditions under the influence of multiple factors,such as equivalent TNT quality,buried depth of subway station and site soil conditions,and puts forward the prediction formula of ground vibration speed and acceleration under the influence of multiple factors.Based on the response analysis of the ground building structure under the explosion in the subway station,the safe distance of the ground building is suggested.(2)Three typical finite element models of subway station-upper cover frame structure,frame shear wall structure and shear wall structure are established to analyze the dynamic response of subway station under explosion.Based on the criteria of concrete cracking and component damage,the structural deformation,internal force and vibration velocity under different explosive equivalent are calculated,the critical vibration velocity of structural cracking damage is studied,the vibration safety assessment of the upper cover structure is carried out,the different responses of three typical structures are compared,and the reasonable structural form is recommended for engineering application.(3)The dynamic response of the roof of the subway station under the explosion of an underground station is analyzed,and the failure mechanism is studied.Based on its damage condition,two kinds of protective measures,namely external foam aluminum and grid sandwich plate,are a used for explosion protection and explosion reduction analysis.The results show that the peak stress of roof is reduced by 59.7%,the ground vibration velocity decreases by 64.5%,and the vibration velocity of the upper cover decreases by 57.6%.The peak value of roof stress can be reduced by 60.8%,the peak value of ground vibration velocity can be reduced by 61.3% and the peak value of top cover structure vibration velocity can be reduced by 58.8% by using grid sandwich plate protection,which proves the effectiveness of the two measures. |
