Dynamic Response And Damage Assessment Of Underground Composite Pipe Corridor Under Gas Explosion Load

In recent years,China's urbanization construction is progressing steadily,and natural gas,as a clean energy is bound to be gradually popularized and developed.However,the explosion accidents caused by the accidental condensation of combustible gas occur from time to time.The gas explosion not only directly threatens the safety of people's lives and property,but also may cause the continuous collapse of adjacent buildings and other major accidents.Undergro--und comprehensive pipe corridor is an important part of the underground space of the city.If the gas pipeline enters the corridor,the gas is likely to leak out accidentally during the transportation in the corridor and cause an explosion.The consequences are unimaginable.Th--is article is based on cast-in-situ monolithic practical project as the background of urban underground pipe,using ANSYS/LS-DYNA software,based on the material of fluid-solid coupling algorithm and typical gas explosion load mechanical model,two methods for underground comprehensive utility tunnel gas in gas explosion propagation law of shock wave,the pipe gallery structure dynamic response and meet wall damage assessment was studied,the main research work is as follows:(1)Establish the finite element model for the analysis of the explosion flow field in the gas tank in the underground comprehensive pipe corridor,conduct numerical simulation of the gas explosion process in the gas tank,and obtain the propagation process of the blast wave,the pressure cloud map of the shock wave,the isobaric cloud map of the overpressure peak,and the surface of the overpressure peak of the shock wave,etc.For different conditions of methane-air mixed gas volume in the finite element model of gas explosion chamber and extract the overpressure time history curve of air units,verify get 9.5% concentration of methane gas mixture produced by the explosion overpressure peak is the largest,but also put forward in the same concentration of methane gas from gas overpressure peak value of different distance to the outer curve of the mathematics analytic expression.Through MATLAB software,the simulation results are further arranged to obtain seven different concentrations and volume of methane-air mixture gas from the outer edge of the gas,gas concentration or volume,air explosion shock wave overpressure peak surface fitting formulas.(2)Set up "Gas-Air-Structure-Soil" the finite element model of fluid-solid coupling interaction,the dynamic response of underground pipe gallery has carried on the numerical simulation of the reinforced concrete inside and outside in the process of explosion was formulated,main soil reinforced measuring point,the internal partition wall and ground station of dynamic response,including stress,strain time history curve,such as reinforced concrete axial stress time history curve and stress wave propagation process in the surrounding soil body,causes the ground vibration characteristics and attenuation law,etc.The direct loading method based on the superpressure peak surface formula of the gas explosion and the fluid-solid coupling method of the gas explosion were used for numerical simulation respectively.(3)Establish P-I damage evaluation criteria for underground composite pipe corridor wall panel under gas explosion load based on bearing Angle,and obtain P-I curve and corresponding curve fitting calculation formula of underground composite pipe corridor wall panel under gas explosion load by means of numerical simulation trial calculation.