Design And Research On Gas Explosion Protection Measures For Urban Underground Integrated Pipe Gallery

With the large-scale construction of urban underground integrated pipe corridors and the promotion of gas inlet corridors,the impact of gas explosion on the entire structure must be highly valued.Every year,gas explosions occur frequently in the world.Especially the shallow buried pipe corridors are more prone to gas leakage after the earthquake.Once the gas explosion,the health assessment or safety evaluation of the entire pipe structure is very difficult.Or the reinforcement design is very difficult.At present,there are few studies on gas explosions in underground large spaces such as integrated pipe corridors.At present,there are few studies on gas explosions in underground large spaces such as integrated pipe corridors.Based on ANSYS/LS-DYNA large-scale finite element software,this paper numerically simulates the gas explosion shock wave propagation law and the dynamic response of the pipe gallery.The main research contents are as follows:(1)Using the ANSYS/LSDYNA software,a three-dimensional gas-air model was established to simulate the gas explosion shock wave propagation cloud pattern in the gas gallery of the integrated pipe gallery and the overpressure attenuation at different positions on the central axis of the gas tank.The curve and the attenuation law of the explosion shock wave are analyzed.It is proved that the maximum overpressure of acetylene-air mixture is greater than the maximum overpressure of methane-air mixture.The blast load and shock wave propagation velocity increase with the increase of gas volume.Large;using the overpressure-time curve of the four explosion center unit,take 8 points on the curve as a simplified blast load curve.(2)A three-dimensional finite element model of integrated pipe-soil is established.The parameters of the equivalent element are calculated according to the corresponding formula,and the viscoelastic boundary is added at the boundary of the soil.The detonation wave reflection is applied to the wall of the pipe around the gas tank.According to the pressure curve,the dynamic response curves of displacement,velocity and acceleration at different positions of the integrated pipe gallery are obtained.By comparison,it is found that the gas-fired panels have greater dynamic response than the other cabins,and the left-hand panel of the gas tank is most vulnerable to damage.And the damage is the most serious,the gas tank is prone to collapse.As the distance from the explosion zone is farther,the dynamic response of the pipe gallery becomes smaller,and the damage of other cabins is not serious.(3)According to the anti-explosion principle of the building,it is proposed that the gas tank should adopt the maximum anti-explosion intensity when carrying out anti-explosion design,but for other compartments of the integrated pipe gallery,the fortification intensity can be reduced according to the situation;according to the protection level,the integrated pipe gallery should be set up.For medium protection level,that is,after a large-scale gas explosion in the gas engine,the pipe gallery will not collapse continuously,allowing partial damage,but it can be repaired and put back into use.The reinforcement effect of the steel plate in the gas compartment is simulated and analyzed.The change of the effective stress of the unit after the different thickness of the steel plate is pasted in different positions of the gas tank proves that the 6mm thick steel plate can be effectively applied to the pipe gallery through the anti-explosion reinforcement design.