Study On Fire Safety Countermeasure In Single Highway Tunnel For Subtended Traffic

With the fast development of the highway, the second-class highway has also got substantial progress, and the extra long single-tunnel for subtended traffic has also increased gradually. The characteristic of single-tunnel for subtended traffic is small traffic, low-speed,big fire hidden trouble, higher difficulty evacuating and succoring. Once a fire happened in the Single-tunnel for subtended traffic, it will bring about gigantic economic losses and grave social influence, and study on fire safety countermeasure in single-tunnel for subtended traffic at home and abroad is still in the junior stage. Therefore, how to resolve the disaster prevention and rescue of the single-tunnel for subtended traffic becomes more and more important.This article is for the problem of fire safety countermeasure in Single-tunnel for subtended traffic, relying on the project "Operating ventilation, lighting and security technology research of tunnel for subtended traffic" of Yunnan Province traffic science and technology plans carrying out fire safety measures research. By analyzing the causes and clsssification of fires, the security for fire scale of single-tunnel for subtended traffic can be classed 3MW, 10MW, 20MW, and the corresponding level is mini-scale fire, medium-scale fire, large-scale fire.After the fire occurred in the tunnel, the distribution of smoke, temperature and pressure field is very complex. In this paper, with the finite element numerical simulation analysis of characteristics of fire's steady-state and transient field, the result is got that six minutes at the beginning of the fire is the prime time to escape. When the tunnel get a fire, tunnel ventilation organizational arrangements should be comprehensive analyzed and specifically determined based on different factors, the evacuation of passengers and drivers should accord to the location of fire points; the scale of the fire, the direction of the fire wind pressure; the airflow impacted by the pressure inside the tunnel; the time when the fire happens, is found and wind machine is adjusted; the speed of the smoke flow and temperature spread inside the tunnel under fire condition; the back-flow of the smoke and so on. Rescue plan should be considered according to the factors above, toxic smoke should be exhausted through the path as short as possible in the vertical ventilation. Controlling the smoke-exhaust wind speed is prime in the tunnel with the horizontal and semi-transverse ventilation.In the study of fire safety countermeasure, the concept of building performance-based disaster prevention is introduced into the design of the tunnel, and the tunnel fire prevention countermeasures are divided into performance-based countermeasures and structured countermeasures, making a more clear idea of prevention. According to the performance-based countermeasures, different modes of ventilation for the subtended traffic tunnel, analysis of the air-flow organization and the model of escape and rescue at the time of fire conditions are carried out and the rescue modes of ventilation under different conditions in different points are given.According to the structured countermeasures, the separation model between men and smoke and the separation model between men and fire are put forward. The prevention disaster model of closed single maintenance of tunnel and the fuzzy control method of fire disaster of tunnel are brought out in the separation model between men and smoke. The single track vehicles model and the subtended traffic single-tunnel two-way turned into two-hole single lane one-way model are given. Simultaneously, the disaster prevention and rescue mode with single-hole two-lane tunnels turned into upper and lower levels of single lane tunnel is proposed.For the fires and dangerous goods, which are greater than 20MW in the fire scale classification, rationalization proposals of transport to single-hole subtended traffic are given.