Fire Protection and Evacuation Analysis in Underground Interchange Tunnels by Integrating BIM and Numerical Simulation

Abstract

Rescue and evacuation of underground interchange tunnels after a fire are challenging. Therefore, a method of integrating building information modeling (BIM) and a fire dynamic simulator (FDS) was proposed to analyze fire characteristics and personnel escapes in underground interchange tunnels. A BIM model of underground interchange tunnels was built, and then different formats (DXF and CAD) were generated and imported into Pyrosim software and Pathfinder software. With an increase in ventilation velocity, the CO concentration and temperature downstream of the fire source increased, and visibility decreased, according to simulation results. The critical ventilation velocity was 3.6 m/s at 30 MW. Evacuation simulation results suggested that the congestion of the transverse passage was very unfavorable for personnel escape: the escape time increased by 14.9% and 20% when the interior and entrance of the transverse passage were severely congested, while a 2.5 m wide transverse passage effectively reduced the escape time. Visibility was the first indicator that it did not meet the safety of the escape. After the tunnel’s personnel have been evacuated, the air supply or exhaust system should be started, and smoke should be expelled at a higher velocity. It is necessary to clear the passageway quickly or increase the automatic firefighting facilities when congestion is severe.