长大公路隧道纵向排烟与人员疏散特性研究

Research on Performance of Longitudinal Smoke Extraction Strategy and Personnel Evacuation in Road Tunnel

为研究城市公路隧道发生火灾时纵向排烟风速对隧道内部疏散救援环境的影响及被困人员的逃生问题,首先运用FDS软件建立了某隧道的数值模型,通过模拟三种不同纵向风速作用下的火灾工况,得到了火源下游主隧道内及横通道内温度场、能见度的分布规律。结合计算结果,运用仿真模拟法对多组横通道参数取值情况下共计25种疏散工况进行模拟,得到了横通道间距及宽度对人员疏散时间的影响规律,选取其中9种典型计算工况对人员的疏散逃生情况进行分析研究。研究发现:(1)提高纵向风速可改善火源下游主隧道内的疏散环境,但会对500 s后横通道内的疏散环境产生不利影响;(2)增大横通道宽度或间距均能减小隧道内被困人员的疏散时间,但对于本工程而言,合理的宽度取值范围为1.5~2.0 m;(3)横通道间距为200 m时,1.5~2.0 m的横通道宽度均可满足人员安全疏散要求;横通道间距为250 m时,建议采用2.0 m的横通道宽度取值;横通道间距为300 m时,建议取横通道宽度为2.0 m,且应控制纵向风速不大于3.5 m/s。

In order to study the influence of longitudinal wind speed on evacuation and rescue environment in urban road tunnel and the escape of trapped people in case of fire,this study first establishes a numerical model of a tunnel by using FDS software.By analyzing three fire conditions with different longitudinal wind speeds,the distribution of temperature field and visibility in the main tunnel and cross passage downstream of the fire source are obtained.Based on the calculation results and with the help of simulation method,a total of 25 evacuation working conditions with different cross passage parameters are simulated and the influence law of cross passage′s spacing and width on evacuation time is obtained.In addition,9 typical calculation conditions are selected from the above 25 conditions to simulate the evacuation situation.The study concluded that:(1)increasing the longitudinal wind speed can improve the evacuation environment in the main tunnel downstream of the fire source,but it have adverse effects on the evacuation environment of cross passage after 500 s;(2)increasing the width or spacing of cross passage can reduce the evacuation time of trapped people in the tunnel.But for this project,the reasonable width ranges from 1.5 m to 2.0 m;(3)when the spacing of cross passage is 200 m,the width of 1.5-2.0 m can meet the requirement of safe evacuation.When the spacing of cross passage is 250 m,the width is suggested to be 2.0 m.When the cross passage spacing is 300 m,it is suggested that the width should be 2.0 m and the longitudinal wind speed should be controlled not more than 3.5 m/s.