| In recent years,urban underground space engineering has developed rapidly.In many big cities,the construction of subway and comprehensive pipe gallery has become an important part of urban development,so the potential risks in its operation have also attracted much attention.Especially when gas explosion occurs in the pipe gallery,it will not only destroy the pipe gallery itself,but also affect the subway tunnel running below.Therefore,it is meaningful to study the influence of adjacent subway tunnels under the action of pipe gallery gas tank explosion.Based on an engineering example,the calculation model is established by using ANSYS / LS-DYNA finite element analysis software,which is based on 9.5% gas explosion concentration.Firstly,the influence law of the explosion equivalent on the dynamic response of the pipe gallery structure is analyzed.Secondly,the influence of the buried depth of subway tunnel on the tunnel structure is analyzed according to the large explosion equivalent.Finally,on the basis of the severe buried depth of the dynamic response,the influence of the relative zenith distance and spatial angle between the pipe gallery and the tunnel on the dynamic response of the tunnel structure is analyzed.The main conclusions are as follows:（1）The explosion equivalent method is used to calculate the maximum impact of explosion in the gas separation tunnel,and the TNT equivalent method is used to simulate the explosion in the gas separation tunnel.The results show that the maximum explosion equivalent of the gas tank is 160kgtnt;The middle of the pipe gallery wall plate is most affected;Controlling the amount of gas leakage can effectively reduce the dynamic response of pipe gallery results;Moreover,due to the action of earth pressure,the response on the bottom plate of the gas cabin is slightly less than that on the side plate.（2）Based on the pipe gallery simulation,the working condition of tunnel buried depth is simulated（pipe gallery buried depth 2m,explosion equivalent 160kgtnt）,and the action law of buried depth on subway tunnel is studied.The results show that the response of subway tunnel will weaken with the increase of buried depth;The influence of gas explosion in pipe gallery on tunnel structure can be reduced by increasing the buried depth of subway tunnel;It is recommended that the buried depth of the tunnel should not exceed 10 m.（3）Based on the simulation of tunnel buried depth,the working condition of zenith distance is simulated,and the influence law of zenith distance on tunnel structure is studied.The results show that the tunnel response is higher when the zenith distance is0 ° and 15 °;The dynamic response of tunnel structure is negatively correlated with the zenith distance;With the increase of zenith distance,the attenuation rate of vertical response is less than that of horizontal response.（4）Based on the simulation of tunnel buried depth,the spatial angle simulation is established,and the influence law of spatial angle on tunnel structure is studied.It can be concluded that under the constant depth,the two underground structures are safer when they are vertical than when they are parallel;The larger the space angle,the weaker the deformation and vibration of the tunnel structure;Therefore,for projects with small spatial angle,the buried depth of the tunnel can be increased to reduce the dynamic response of the structure. |
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