Research on the protection mechanism of methane explosion in underground space by flexible construction

Urban growth has promoted the use of underground spaces, where explosion accidents can be catastrophic. In this study, we investigated the effect of placing flexible construction in front of rigid obstacles on methane explosion protection by using an experimental platform and adjusting the blockage rate and spacing of the obstacles. It aims to reduce the risk of gas explosions in urban underground spaces. The results of the study show that the flame propagation peak speed and peak overpressure are reduced with the decrease in the blocking rate of the flexible obstacle when the blocking rate of the flexible obstacle is less than or equal to the blocking rate of the rigid obstacle, with the decrease in the spacing, the better the protection effect of the methane explosion. When the blockage rate of the flexible obstacle is greater than the blockage rate of the rigid obstacle and spacing is less than the height of the flexible obstacle, rigid and flexible obstacles are connected as a whole, increasing the strength of the explosion. This study can provide a theoretical basis and scientific guidance for optimizing rigid and flexible object hybrid layouts and methane explosion protection technology in urban underground spaces. • Research contributes to optimizing the layout of underground space and mitigating blast damage. • Research can provide a reference for open-space blast protection technology. • Placing the flexible obstacle in front of the rigid obstacle may affect peak overpressure and flame velocity. • The key condition is that the flexible obstacle blockage rate be less than or equal to the rigid obstacle blockage rate.