特长公路隧道内的横通道间距和车行间距研究

隧道火灾,尤其是长大公路、铁路隧道火灾,往往是灾难性的。因此,基于性能化防火设计原理,对雪峰山特长公路隧道的横通道间距和车行间距进行了研究。对中等规模20 MW的火灾,按照规范建议的3 m/s的风速进行通风的情况下,先用CFD软件模拟计算火灾危险时间Tfire,然后由疏散模型中的经验公式计算人员疏散时间Tevac,比较分析不同横通道间距下人员疏散的安全性;同时为了避免隧道内车辆间的引燃,利用辐射换热原理,对车辆间的火灾蔓延性进行了分析。模拟结果为:最佳横通道间距约为290 m,最小引燃间距为6 m。考虑到建设成本的问题,建议雪峰山隧道的横通道间距改为300 m;同时,考虑到后继车辆的刹车及不同的行车速度等因素,建议特长隧道内车距最好要大于110 m;

A Research on Cross Passage Spacing and Car Spacing in an Extra-long Highway Tunnel

Fire accidents in tunnels especially in long-span tunnel and extra-long tunnels are always disastrous.Therefore,cross passage spacing and car spacing in Xuefengshan extra-long highway tunnel is studied on a basis of the principle of performance-based fire design by a computational fluid dynamics(CFD) software.In order to evaluate evacuation safety under different cross passage spacing,fire risk times Tfire is firstly got through simulations of a medium size fire,of which the heat release rate(HRR) is 20MW with a longitudinal velocity of 3m/s suggested in Code for Design of Road Tunnel of 2004.The evacuation times Tevac is calculated by an empirical formula in the evacuation model.Meanwhile,fire spreading to other cars is analyzed by radiation theory.The results indicate that the optimized cross passage spacing is 290m and the smallest igniting spacing between cars is 6m.Taking construction costs into account,the suggested cross passage spacing in the Xuefengshan highway tunnel is 300m. Considering the factors of braking and different vehicle's running speeds,it is suggested that space between cars should be greater than 110m in extra-long highway tunnel.