Abstract: The gas explosion effect of pipe galleries seriously endangers urban development and social life stability.Studying the load characteristics and effect of gas explosion has guided significance of the optimal design of pipe gallery structure.The similarity model test of gas explosion in urban pipe gallery was designed,and the time history curve and pressure distribution characteristics of gas explosion shock wave under different methane concentration were analyzed.The calculation formula of the peak displacement response of the structural roof under the action of the gas explosion load is theoretically deduced,and the theoretical calculation results of the displacement response are verified by combining the model experiment results and numerical simulation results.The results show that when the concentration of methane is 9.5%,the peak overpressure of gas explosion is higher than the concentration of 10%.In this case,the peak value of overpressure depends on the concentration conditions of gas explosion.Under the test conditions,the size of the overpressure peak depends on the concentration conditions of the gas explosion.The gas explosion overpressure time-history curve has a boosting time of 500~700 ms,and the overpressure action time is about 1 500 ms,the action time of explosion overpressure is directly related to the size of the model.The peak overpressure at each measuring point is evenly distributed,which can be approximated as a time-varying uniform load.The study results show that the given calculation formula for roof displacement response is effective and can be used to calculate the roof′s maximum displacement under the action of gas explosion loads.

Key words: pipe gallery,gas explosion,model test, overpressure peak,displacement response