Study On The Fire Spread And Evacuation Of Highway Tunnel

With the rapid development of highway tunnel construction in China, up to 2012, the total length of highway tunnel in our country has reached 6253.4 km. The tunnels number and length is growing and the potential of tunnel fire and vehicle accidents are gradually increasing. The FDS simulation software is used to set different fire scene. The principle of tunnel fire are also analyzed. The available safety egress time(ASET) is determined and the required safety egress time(RSET) is calculated by using the experience formula. On this basis, We determine the plan that is suitable for the personnel evacuation. The main research results and work are as follows:(1) Through the statistical of all kinds of tunnel fire accidents, the causes, classification and characteristics of tunnel fire are summarized. At the same time, the serious harm of the high temperature smoke is analyzed.(2) The flue gas flow model and the distribution of temperature are researched when fire occur in a highway tunnel. The generation of tunnel fire smoke, reflux and resistance of ventilation to flue gas flow are analyzed theoretically. The curve of tunnel temperature change and the distribution of temperature field are researched.(3) Three kinds of fire scene are established basing on the tunnel Xihua. By using FDS software fire spread characteristics are simulated. Firstly, the rules of fire development is simulated in fire downstream area. The available safety evacuation time is be calculated.. Secondly, analysis the rule of different ventilation speed(2m/s, 3m/s and 4m/s), temperature, flue gas and visibility, and to determine that under the various fire conditions, required for safe evacuation time. The results show that when mechanical wind speed is 2m/s,the phenomenon of upstream smoke backflow is more serious. When the mechanical wind speed is 3m/s the fire smoke spread can be effectively controlled in fire upstream area, and a few trapped people can be escaped in the downstream area. However, when the mechanical wind speed is 4m/s a few trapped people can’t be escaped in the downstream area, because the CO concentration and temperature spread rapidly in the downstream area. Finally, the high power(100MW) fire in the tunnel is simulated and the distribution of the temperature and CO concentration in every section of the tunnel is given. We also put forward the corresponding control measures.