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为研究火灾初期时大断面道路隧道内温度及烟气流动特性,在三车道大断面试验隧道内进行了足尺火灾试验。试验考虑了0.5 MW、1 MW及5 MW三个等级的火灾规模;试验纵向风速范围为0~2 m/s。试验结果表明:在火灾发展初期,火灾规模和纵向风速是影响大断面道路隧道内温度场分布及烟气扩散的重要因素;隧道火灾产生的高温烟气趋于向拱顶扩散,故隧道横截面高温区域分布于隧道上部空间,靠近地面的空间温度则较低。火灾规模越大,隧道横截面的高温区域范围越大。大断面隧道因隧道内空间较大,有利于烟气扩散和人员逃生。然而,火灾预警的角度考虑,大断面隧道需多在关键截面上设置温度传感器和摄像头,以获得更为有效的火情信息来组织灵活的疏散逃生方案。
In order to study the temperature and smoke flow characteristics of tunnels with large section in the early stage of fire, a full-scale fire test was conducted in a three-lane large-section test tunnel. The test considered the fire scale of three levels of 0.5 MW, 1 MW and 5 MW; the test longitudinal wind speed range was 0-2 m / s. The results show that in the initial stage of fire development, the scale of fire and longitudinal wind speed are the important factors affecting the temperature field distribution and smoke diffusion in tunnels with large cross-section. The high-temperature flue gas from tunnel fire tends to diffuse to the dome, The high temperature area is located in the upper part of the tunnel, and the space temperature near the ground is lower. The larger the fire, the larger the cross-section of the tunnel is in the high temperature range. Due to the larger space in the tunnel, the large section tunnel is favorable to the smoke diffusion and personnel escape. However, in the aspect of early warning of fire, large-area tunnels need to set up temperature sensors and cameras on critical sections to obtain more effective fire information to organize flexible evacuation escapement plans.