Abstract:

A multi- scale simulation method coupled with threedimensional field simulation and one-dimensional network simulation was used to study the natural propagation of smoke when the train is on fire at the middle and the fans in adjacent stations are closed. The slopes of the long subway interval tunnels are 0‰ , 12‰ , 21‰ and 30‰ . The influence of slope on smoke diffusion and control in tunnel fire was analyzed. Comprehensive analysis on factors such as temperature, CO concentration and visibility was carried out, the danger of tunnel environment changes over time in the initial stage of the fire was studied and the available safe evacuation time for personnel was obtained. When the train is blocked in the gradient section of the section tunnel and the gradient reaches 30‰ , there is a step change of CO concentration in the tunnel because of the backflow phenomenon. 

Key words: subway, interval tunnel, slope, smoke propagation, multi-scale simulation