高海拔公路隧道火灾特性及安全疏散时间研究

Research on Fire Characteristics and Safe Evacuation Time of Highway Tunnel at High Altitude

为探明高海拔公路隧道火灾烟气及温度扩散规律,得到高海拔条件下人员安全疏散时间,采用理论分析、现场试验、数值模拟等手段,取得如下成果:高原环境大气密度及空气含氧量随着海拔的升高下降明显;高海拔地区相较于平原地区火灾燃烧的热释放速率低143%,燃烧时间延长186 s;燃烧稳定后,高海拔隧道火灾最大纵向烟雾扩散速度比平原隧道大12.1%,最大横向烟雾扩散速度比平原隧道大12.5%,相同火灾规模情况下高海拔隧道最高纵向温度比平原隧道高16.5%,最高横向温度比平原隧道高5.7%,高海拔隧道整体温度要高于平原隧道;在30 MW火灾规模下,人员可用安全疏散时间与距火源点距离成正比,当距离火源点300 m处人员可用安全疏散时间达到506 s。研究成果可用于指导羊八井隧道人员安全疏散,同时也可为类似工程防灾救援提供参考借鉴。

In order to find out the law of fire smoke and temperature diffusion in high-altitude highway tunnels,and obtain the safe evacuation time of personnel under high-altitude conditions,theoretical analysis,field tests,numerical simulation and other means are adopted.The following results are obtained:with the increase of altitude,the atmospheric density and air oxygen content in the plateau environment decrease significantly;the heat release rate of fire burning in the high-altitude area is 143%lower than that in the plain area,and the burning time is prolonged by 186s;the maximum longitudinal smoke diffusion velocity of the altitude tunnel fire is 12.1%higher than that of the plain tunnel;the maximum lateral smoke diffusion velocity is 12.5%higher than that of the plain tunnel;under the same fire scale,the highest longitudinal temperature and the highest transverse temperature of the high-altitude tunnel are 16.5%and 5.7%higher than those of the plain tunnel.The overall temperature of the high-altitude tunnel is higher than that of the plain tunnel;under the fire scale of 30MW,the safe evacuation time of personnel is proportional to the distance from the fire source.If the distance from the fire source is 300meter,the safe evacuation time of personnel will reach 506s.The research results are used to guide the safe evacuation of personnel in Yangbajing Tunnel,and can at the same time provide reference for disaster prevention and rescue of similar projects.