地铁点式换乘车站火灾烟气扩散特性及控制策略研究

The fire design and safe operation of interchange station between two lines are key technical problems in the development of urban subway transit network. Current research and metro fire design code are mainly restricted to smoke propagation and control in the fire scenario of a single subway station and subway tunnel. Fire safety technologies for subway transfer stations have not been studied systematically. The interchange stations between two lines which are commonly constructed in China are chosen as the research object. For the deep-buried interchange station with complicated internal structure, multiple portals and exits, typical fire scenarios can be established by comprehensively considering characteristics of fire source, internal structure of interchange stations. Smoke propagation characteristics in different fire scenarios are studied by integrating the methods of theoretical study, numerical simulation and experiment. The stack effect, train induced piston effect, mechanical air exhaust and supply effect are considered in the study of smoke propagation. Based on the results, the parameters are selected and criteria for evaluating the dangerous level of smoke propagation in the interchange station are proposed in order to inspect smoke control schemes. Consequently, the reasonable and effective integrated control scheme of ventilation and smoke exhaust system can be determined. The reasonable and effective overall operating scheme of ventilation and smoke exhaust system can be determined by comparing different operating schemes. Design method and operation scheme can be summarized by analyzing the research results. This research could provide reference for performance based design and development of safe operation and emergency management programs for urban subway interchange station between two lines.

地铁换乘站的消防设计及安全运营是城市地铁网络化发展需要解决的关键技术问题。目前地铁系统火灾安全的研究以及现有的技术规范仅限于单个地铁车站和区间隧道火灾工况，对换乘站火灾安全缺乏系统性的研究。本项目以国内普遍建设的点式地铁换乘车站为研究对象，针对其埋深大、内部结构复杂、出入口多等特点，综合考虑火源特性、换乘站内部结构特点等因素建立换乘站典型火灾场景；结合理论分析、数值模拟和实验研究三种手段研究点式换乘车站不同火灾场景下的烟气扩散规律，考查浮升力效应、活塞风、机械排烟、补风等因素对烟气扩散的影响。以烟气扩散研究结果为基础，选择衡量换乘站火灾烟气扩散危险性的参数，提出判断烟气控制方案合理性的依据。通过对比不同烟气控制方案效果，确定合理、有效的换乘站通风排烟系统的整体运行模式。研究成果可以为开展地铁点式换乘站性能化防火设计和制定安全运营及应急管理预案提供参考。

地铁换乘站的消防设计及安全运营是城市地铁网络化发展需要解决的关键技术问题。针对不同类型点式换乘车站（“十”型、“T”型、“L”型），采用理论分析、数值模拟和实验研究（现场实验和模型实验）等手段分析了不同火灾场景下的烟气扩散规律及有效控制策略。. 主要研究成果包括：1）确定了衡量换乘站火灾烟气扩散危险性的参数以及判断烟气控制方案合理性的依据，即换乘楼梯处抑制烟气向上部空间扩散的有效风速以及着火站台烟气层的高度。发生火灾时，需维持换乘楼梯向下风速不小于1.5m/s；着火站台烟气层高度维持在1.8m以上，能保证车站所有的人员可以安全疏散；2）提出了点式换乘车站（“十”型、“T”型、“L”型）火灾烟气综合控制方案。对于地下三层“十”字形换乘站，其中之一站台发生火灾时需要与本车站相连的区隧道进行排烟但需启动换乘站的另一站台进行有效补风；对于“T”和“L”换乘站，发生火灾的单站排烟可以有效控制烟气，两个站台相连部位的防火卷帘放置高度可以维持在人员安全疏散高度。对于换乘部位，可以采取固定式排烟系统和移动式排烟系统联合进行烟气控制。. 项目研究紧密结合《关于推进城市安全发展的意见》中安全战略发展方向，研究成果可以用于地铁点式换乘站性能化防火设计、火灾风险评估、应急管理预案和决策制定，可以有效指导地铁系统安全运营，弥补现有地铁设计规范的关于换乘站消防管理规则条文的局限性和空白。