| Utility tunnel construction is one of the key livelihood projects in China at this stage,and utility tunnel safety is a strong guarantee for the normal operation of the city.At present,the research on integrated pipe corridor mainly focuses on the optimization of pipe corridor cross-sectional form,gas into the corridor,rainwater and sewage into the corridor,pipe corridor fire and safety operation,etc.,the research results on the safety of the corridor after the gas explosion are still rare,and the gas chamber anti-explosion design is not more reflected in the specification.The gas explosion of the gas chamber is a potential danger for the safe operation of the integrated corridor,so the study of the structural dynamic response of the integrated corridor under the effect of gas explosion has a certain practicality and urgency.Relying on a key project of a comprehensive pipe passageway in Beijing,this paper intends to use the large-scale finite part analysis software system ANSYS19.0/LS-DYNA to determine a multi-material coupled system model of pipe passageway structure-air-gas mixture,and to numerically simulate the gas explosion by considering material nonlinearity,geometric nonlinearity,contact nonlinearity,multi-material coupling interaction,etc.,with the gas mixture because the explosion supply.The most purpose of the study is to analyze the propagation law of gas explosion wave within the integrated passageway and also the structural dynamic response of the integrated passageway underneath the result of gas explosion,so as to supply a precise research project basis for the explosion-proof and anti-detonation style of the integrated passageway.Through ANSYS19.0 / LS-DYNA numerical simulation,the propagation law of gas explosion shock wave in utility tunnel under different gas concentrations(8.2%,9.5%,11.6%)and different gas cabin sizes(1.9m×3.4m×6.0m,1.9m×4.0m×6.0m,2.2m×4.0m×6.0m)was analyzed.The results show that the pressure of the measuring points near the gas explosion center is relatively large,and the pressure of every mensuration purpose within the same section decreases with the rise of distance from the explosion center.Since the gas explosion shock wave will reflect many times over time in the gas tank,each measuring point will experience many pressure peaks.Especially,the pressure at the measuring point at the inner wall of the gas tank will be significantly increased after the superposition effect of multiple reflected waves.When the gas concentration is 9.5%,the peak overpressure of the gas unit is the largest,the energy released is the largest,and the maximum velocity diffuses around,making the compression wave velocity faster.Therefore,the propagation velocity and influence of the gas explosion shock wave are also the largest.The propagation velocity of gas explosion shock wave is negatively correlated with the size of gas tank,as does the explosion load.In this paper,the structural dynamic response of the utility tunnel under gas explosion is studied under different gas concentrations(8.2%,9.5%,11.6%),different gas cabin sizes(1.9m×3.4m×6.0m,1.9m×4.0m×6.0m,2.2m×4.0m×6.0m),different cabin numbers(single cabin,double cabin,three cabins,four cabins)and different layers(one layer,two layers).The research shows that when the gas concentration is 9.5%,the peak velocity,peak acceleration,peak displacement and stress of the gas cabin in the utility tunnel are all greater than those of 8.2% and 11.6% of the gas concentration,so the explosion load has the greatest damage and influence on the gas cabin in the utility tunnel.With the increase of the gas tank size,the air in the tank vibrates,the temperature rises,and the shock wave continuously reflects and overlays,which consumes the energy caused by the explosion.Therefore,the damage and influence of the explosion load on the gas tank of the utility tunnel are gradually reduced.With the increase of the number of utility tunnel cabins,the stress is transmitted in the wall of the utility tunnel outside the gas tank,which causes the continuous vibration of the other walls,consumes part of the energy,and buffers the impact of the explosion shock wave on the gas tank.So the impact of the explosion load on the gas compartment of the integrated pipe gallery and damage gradually reduced and gradually tends to smooth out.With the increase in the number of layers of the integrated pipe corridor,the stress is transmitted in the wall outside the gas tank,which plays a buffer,energy dissipation and explosion effect.The influence and damage of the explosion load on the gas tank of the utility tunnel are gradually reduced. |
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