Experimental study of smoke spread in titled urban traffic tunnels fires

摘要

More and more urban traffic tunnels are built due to the heavy traffic in dense urban areas. Fire safety in tunnels is a concern due to the large traffic flow. Most of the urban tunnels have slope. Knowledge on smoke spread in titled tunnel is still limited. Experimental studies on the smoke spread in a titled tunnel are carried out by the reduced-scale tunnel model tests and will be discussed in this paper. Effects of the titled gradients and longitudinal ventilation speed on the temperature distribution and smoke stratification downstream from the fire along the tunnel will be studied The results show that the smoke spread upwards much faster with the slop gradient increasing, and a thick smoke layer was formed when smoke moved to the upward part of the tunnel and filled it up. The ventilation speed had a great influence on temperature distribution along the tunnel, and the smoke stratification will be distributed when the longitudinal ventilation speed becomes large. Lower ventilation speed should be adopted at the beginning to ensure the smoke downstream of the fire keep stratified to give the tunnel users more time to escape.