地铁隧道火灾烟气蔓延和人员疏散效率研究

Study on smoke spreading and evacuation efficiency in subway tunnel fire

地铁隧道属于狭长受限空间,发生火灾后具有烟气蔓延速度快、人员救援难度大等特点。疏散平台和疏散门作为火灾时人员逃生的主要途径,合理的设置可提高人员疏散效率,保障人员安全。研究地铁隧道人员安全疏散可靠度,可为安全疏散设施设置提供决策依据。为研究地铁隧道火灾时隧道内火灾烟气特性和人员疏散的效率,基于Fire Dynamics Simulator(FDS)和Pathfinder模拟的手段,建立地铁隧道火灾模型和人员疏散模型,分析地铁隧道火灾烟气扩散规律,研究疏散门间距和疏散通道宽度对人员疏散效率的影响。研究结果表明:在2.3 m/s的纵向通风条件下,即便车厢内存在少许烟气,仍可将地铁区间隧道内的烟气控制在火源的下游侧。依据地铁隧道内温度、能见度以及CO浓度等因素确定的人员可用安全疏散时间为30 min。在疏散门间距为150 m的条件下,疏散平台宽度和疏散时间之间相应的拟合关系式为t=−604.55w+1230;在疏散平台宽度为0.7 m的条件下,疏散门间距和疏散时间之间相应的拟合关系式为t=−0.075b+22.03b−809.2。在满足建筑界限的同时,为达到较高的人员疏散效率,可将疏散平台宽度和疏散门间距分别设定为1.2 m和80 m。

The subway tunnel is a narrow and long confined space.After a fire occurs,it has the characteristics of rapid smoke spreading and difficult rescue of personnel.Evacuation platforms and evacuation doors are the main ways for people to escape in the event of a fire.Reasonable settings can improve the efficiency of evacuation and ensure the safety of personnel.Research on the reliability of the safe evacuation of subway tunnels can provide the basis for decision-making on the establishment of safe evacuation facilities.In order to study the characteristics of fire smoke in a subway tunnel and the efficiency of evacuation of people during a subway tunnel fire,based on the simulation methods of Fire Dynamics Simulator(FDS)and Pathfinder,a subway tunnel fire model and a personnel evacuation model were established.The smoke diffusion of a subway tunnel fire was analyzed.According to the law,the influence of the distance between evacuation doors and the width of evacuation passages on the efficiency of evacuation was studied.The results show that under the longitudinal ventilation condition of 2.3 m/s,even if there is a little smoke in the carriage,the smoke in the metro tunnel can still be controlled in the downstream side of the fire source.According to the temperature,visibility,CO concentration and other factors in the metro tunnel,the available safe evacuation time is 30 min.When the distance between the evacuation doors is 150 m,the fitting relation between the width of the evacuation platform and the evacuation time is t=-604.55w+1230.When the width of the evacuation platform is 0.7 m,the corresponding fitting relation between the distance of the evacuation door and the evacuation time is t=-0.075b+22.03b-809.2.While meeting the building boundary,in order to achieve higher evacuation efficiency,the width of the evacuation platform and the distance between the evacuation doors can be set to 1.2 m and 80 m,respectively.