Smoke propagation characteristics and influencing factors of high-temperature spiral tunnel fire

A tunnel fire may cause great damage to people, vehicles, facilities and tunnel structures if it is not effectively controlled. Therefore, it is very important to clarify the smoke propagation characteristics and influencing factors that can help to accelerate the removal of fire smoke and reduce casualties and property losses. In order to study the influence of slope, curvature radius and ambient temperature on smoke propagation during the tunnel operation period, based on the high-temperature spiral tunnel in Midi village, Yunnan Province, the internal and external environmental parameters of the tunnel were measured on site and the numerical simulation model was established by using the simulation software FDS, and the control variable method was used to study the fire smoke propagation characteristics of the tunnel with different characteristics. The results show that: the influence of slope on smoke migration velocity is non-linear, the greater the slope is, the greater the change of smoke spreading speed is; the smaller the curvature radius is, the greater the obstruction to smoke migration is, and the slower the smoke migration speed is; high temperature speeds up the smoke exhaust rate in the tunnel but has less promotion of the fire smoke migration.