单向长隧道极端条件下火灾安全疏散研究

Research on Fire Safety Evacuation in Unidirectional and Long Tunnel under Extreme Conditions

为研究严重交通堵塞及逆向自然风对隧道火灾时烟控效果的影响,并为逃生楼梯的参数设计提供依据,针对通风井排出式纵向排烟区段,考虑火灾点正对隧道中部一处楼梯的最不利情况,利用仿真软件建立了二车道长隧道计算模型,并对模型的准确性进行了验证。结果表明:严重交通堵塞单独作用或与逆向风共同作用导致隧道排烟阻力增大,相比于一般隧道状况,应开启区段所有风机,且二者共同作用下的可用时间最少、安全性最低;通过疏散分析,得到火灾下游第1个楼梯为最不利逃生出口,同一楼梯间距下的平均通过率基本持平,各疏散场景下的整体平均通过率与楼梯宽度间呈较好的单指数函数关系,最佳楼梯纵向间距随楼梯宽度的增加线性增大。

To study the influence of severe traffic jams and adverse natural wind on smoke control effect in tunnel fire,and provide foundation for the parameter design of escape stairs,a two-lane long tunnel calculation model is established by using simulation software in consideration of the most unfavorable situation of fire point to a staircase in the middle of the tunnel,and the accuracy of the model is verified.The results show that the severe traffic jam acting alone or combined with the adverse wind leads to the increase of smoke exhaust resistance in the tunnel.Compared with general tunnel conditions,all fans in the section should be turned on,and the combination of the two has the least available evacuation time and the least safe.Through evacuation analysis,it is concluded that the first stair downstream of the fire is the most unfavorable escape exit.The average pass rate under the same stair spacing is basically flat,and the overall average pass rate of each evacuation scenario shows a good single exponential function relationship with the width of the stairs,and the optimal vertical spacing of the stairs increases linearly with the increase of the width of the stairs.