Numerical study on the dynamic response of gas explosion in uneven coal mine tunnels using LS DYNA CESE reaction dynamics model

Abstract

A numerical simulation method combining detailed chemical reaction mechanism of methane deflagration with approximate real tunnel structure was proposed to confirm whether the unevenness of the tunnel wall during coal mine gas explosion can be ignored. The approximate real tunnel model and smooth wall tunnel model were developed using 3D modeling methods. The propagation and attenuation processes of shock waves in the two tunnel models, as well as the different dynamic responses of the two tunnel walls, are compared and analyzed. Research results show that the non-uniformity of the tunnel wall decreases the shock wave overpressure and propagation velocity. the peak overpressure reduction value of the shock wave reached 81.91 kPa, and the shock wave overpressure reaches its peak at an extended maximum time of 7.4 ms. The stress distribution on the approximate real tunnel wall is discontinuous, the propagation speed of stress waves in the bend tunnel is slower, and the duration of high load is relatively low. The displacement of the approximate real tunnel after gas explosion is lower than that of tunnels with smooth walls, and the displacement of most measuring points on the tunnel on the right is only 1/3–1/2 that of the smooth tunnel.