Study On Propagation Law And Dynamic Response Of Explosion Shock Wave In Underground Utility Tunnel

Underground comprehensive pipeline corridor refers to the unified planning,design,construction and management of various municipal pipelines within the city limits,which is the "lifeline" of important infrastructure to ensure the normal operation of the city.With the rapid development of economic construction in our country,urban underground pipe corridor will be laid in a number of domestic cities in the future,which is one of the key livelihood projects in our country at present.Because the city is in a densely populated area,its hidden explosion hazard must be paid special attention to,therefore,the law of shock wave and the structural dynamic response of integrated pipe corridor gas chamber explosion inside needs more and more thorough study.In this paper,taking the underground integrated pipe gallery of a city’s three cabin as the prototype,a reduced ratio pipe gallery structure model was designed and made by the limitation of the test site,and relevant parameters were collected in the field explosion test.Meanwhile,the finite element software ANSYS/LS-DYNA was used for modeling analysis.The calculation results were consistent with the test results,which proved the rationality and accuracy of the finite element model.In order to analyze the blast wave characteristics of the explosion inside the integrated pipe gallery,a three-dimensional finite element model was established for the explosion of TNT with different mass in the gas compartment of the integrated pipe gallery with different aspect ratio sections.The three-dimensional finite element model was used for numerical simulation analysis of the explosion in the gas compartment of the integrated pipe gallery,and the calculation model was selected as the straight roadway.The cross section area of the gas chamber is 4m2,6m2 and 8m2 respectively,and the weight of TNT is 8kg,16 kg and32kg respectively.A total of nine working conditions are set.The results show that the peak overpressure of blast shock wave is proportional to the amount of explosive charge,inversely proportional to the distance from the detonation center,and inversely proportional to the cross-section area of the gas chamber when the gas chamber is exploded in the integrated pipeline corridor.The closer the gas compartment is to the explosion source,the greater the forward impulse is and the more serious the impact of blast wave is.Under the same charge,the smaller the section area of gas tank,the greater the positive impulse.At the same time,the prediction model of overpressure propagation and forward impulse of blast wave in the integrated pipe gallery explosion is derived by using the above analysis results,and the expression formula of the prediction model is fitted by combining the relevant data obtained from the numerical simulation.In order to deeply study the dynamic response and failure law of the pipe corridor structure during internal explosion,the finite element software ANSYS/LS-DYNA was used to analyze the dynamic response and damage of the integrated pipe corridor under different charges.The results show that when the gas compartment explodes in the integrated pipeline corridor,the inner plate of the pipeline corridor is more significantly affected by the charge amount,and the damage caused by the blast shock wave in the X direction is far greater than that in the Y direction.With the increase of the amount of explosive,the dynamic response of pipe corridor structure also increases.However,when the amount of explosive reaches the critical point of failure of the pipe corridor structure,the pipe corridor structure is damaged,and then continue to increase the amount of explosive,the dynamic response of the pipe corridor structure does not increase or even decrease.After the explosion inside the integrated pipe gallery,the gas tank is first affected by the explosion shock wave and produces deformation and damage.With the increase of the amount of explosive in the explosion inside the pipe gallery structure,there will be many depressions and pits,and finally the inner plate of the gas tank will be bombarded through.