Fire Smoke Control and Personnel Safety Evacuation under Dual-train Tracking Mode in Urban Rail Transit Ultra-long Tunnel

Abstract

Objective In urban rail transit, train departure intervals are generally short, leading to situations where two trains travel in the same direction within ultra-long tunnels. In the event of a fire, this scenario can result in significant property damage and casualties. Therefore, it is crucial to study the fire smoke propagation law and personnel evacuation strategies under dual-train tracking mode in ultra-long tunnels. Method Using FDS (fire dynamics simulation) software and Pathfinder software, a fire and personnel safe evacuation model for ultra-long tunnels is established to simulate and analyze the fire smoke propagation law and personnel evacuation under dual-train tracking mode. Result & Conclusion In this mode, if a fire occurs at leading train rear end, the longitudinal ventilation at critical wind speed can ensure the safety of leading train during the fire. When the downstream smoke front propagates at a speed of 3.20 m/s, it will reach the trailing train after 600 seconds and fully cover it after 620 seconds. The smoke temperature attenuates rapidly along tunnel longitudinal direction, which complies with the law of a bi-exponential model. In dual-train tracking mode, reducing the spacing between connecting passages can decrease the total personnel evacuation time, resulting in minimal impact on personnel time taken to leave the train. Opening train end doors and evacuation platform side doors can significantly reduce personnel evacuation time. In the most adverse fire scenario of dual-train tracking in an ultra-long tunnel, personnel evacuation is challenging, but their safety can be ensured by reducing connecting passage spacing.

Keywords

• urban rail transit
• ultra-long tunnel
• dual-train tracking mode
• fire smoke control
• personnel safe evacuation