This paper investigated experimentally the thermal smoke back-layering and critical velocity of the highway tunnel in alpine gorge area with canyon cross wind. A series of small-scale tests were performed using a pool fire as the fire source. The downstream tunnel portal was under the action of canyon cross wind, and the longitudinal ventilation device was set on the upstream tunnel portal. The smoke movement phenomena were studied by changing the velocities of the canyon cross wind and longitudinal ventilation, and the longitudinal position of the fire source in the tunnel. The experimental results indicated that the smoke back-layering length decreases with the increasing longitudinal ventilation velocity, and both the critical velocity and smoke back-layering length increase with the increasing canyon cross wind velocity. This is because the airflow velocity towards upstream in the tunnel increases with the canyon cross wind velocity. In contrast, the downstream smoke spread length of the fire decreases with the increasing canyon cross wind velocity, and increases with the increasing longitudinal ventilation velocity. An equation for the critical velocity was developed by taking the canyon cross wind into account.

本文以峡谷逆风为例，对高寒地区公路隧道的热烟气反层和临界速度进行了实验研究。使用池火作为火源进行了一系列的小型测试。下游隧道门受峡谷侧风作用，上游隧道门设置纵向通风装置。通过改变峡谷的侧风速度和纵向通风以及隧道中火源的纵向位置，研究了烟雾运动现象。实验结果表明，随着纵向通气速度的增加，烟层的回覆长度减小；随着峡谷横向风速的增加，临界速度和烟层的回覆长度均增加。这是因为朝向隧道上游的气流速度随着峡谷的横风速度而增加。相反，随着峡谷横向风速的增加，火的下游烟气扩散长度减小，而纵向通风速度的增加则使下游烟蔓延长度增加。通过考虑峡谷的侧风，建立了临界速度方程。