Analysis of Adverse Load Conditions for Gas Explosion in Utility Tunnel Based on FLACS

In order to explore the adverse load conditions of gas explosion in the utility tunnel, FLACS software is used to establish a utility tunnel gas explosion model and the accuracy of the numerical model is verified by paper test data. Then the influence of ignition position, gas cloud volume and methane concentration on shock wave load caused by gas cloud explosion was studied, and the relation between gas explosion load at position 1 and gas cloud volume, methane concentration was fitted. The results showed that the overpressure peak and impulse ignited at position 1 are larger than that at other positions. In addition, the peak overpressure and impulse increase with the increase of the gas cloud volume, and the rise rate gradually decreased with the increase of the gas cloud volume, the peak overpressure increased first and then decreased with the increase of methane concentration (reaching the peak value between 10.5% and 11.5%), the impulse increased first and then decreased with the increase of methane concentration (reaching the peak value between 10.5% and 12.5%).