地铁是我国目前最常见的轨道交通形制，作为地铁系统中的枢纽节点，地铁地下车站人员高度密集且空间相对狭窄，在火灾事故发生后极易出现严重的人员伤亡和财产损失。针对地铁车站火灾风险凸显的现状，亟需在通风排烟和人员疏散的交叉领域开展深入研究，探索提升地铁地下车站火灾风险防控能力的综合性方法。另一方面，随着住房和城乡建设部逐步推进全文强制性工程建设规范取代现行标准中强制性条文的改革任务，多部地铁消防设计相关标准规范中的强制性条款在新国标颁布后同步废止，使得当前地铁车站消防设计实践中出现较大自主空间，迫切需要科学定量的评估和优化方法支撑。围绕保障火灾场景人员安全这一目标，本文主要从地铁地下车站火灾烟气蔓延理论、火灾风险评估方法以及火灾风险控制优化方法三个方面开展研究，主要研究内容如下：在地铁车站火灾烟气水平同层蔓延规律方面，建立了引入障碍物修正的顶棚温升指数衰减模型，提出了烟气层流经障碍物形成的尾流区长度计算方法。在火灾烟气竖直跨层蔓延规律方面，研究了楼扶梯区域流场时空分布，在楼扶梯顶部截面提出了中轴线流速分布模型，并结合虚拟火源方法建立了烟气控制临界风量模型。在地铁车站人群疏散风险评估方法方面，提出了疏散风险多维度表征参数体系和参数收敛性分析方法，并运用定义的疏散风险因子实现了各风险参数的无量纲化叠加。风险评估结果表明，实际车站中行人在楼扶梯组、闸机组等瓶颈设施处的长时间等待是疏散风险的重要来源。在地铁车站火灾环境暴露风险评估方法方面，提出了基于人员累计剂量的火灾风险因子概念作为表征单个区域火灾风险水平的参数，结合疏散过程中的人员分布作为各区域权重，实现了人员疏散与烟气蔓延过程耦合的风险评估。风险评估结果表明，实际车站中疏散过程漫长且烟气蓄积严重的区域火灾风险水平最高。在疏散设施布局优化方法方面，研究了自适应排队网络模型以开展高效、可靠的人员疏散模拟，建立了基于启发式检索的设施布局迭代优化算法。所获得的车站最优布局通过小幅调整楼扶梯组及闸机组位置，可明显降低车站疏散风险水平。在通风排烟设施布局优化方法方面，建立了地铁车站排烟系统性能评价参数体系，提出了地铁车站排烟口设计优化流程，从通风性能、排烟效果和火灾风险维度定量分析了地铁车站排烟口朝向、长宽比及间距的最佳设计参数。
Subway has become the most common form of rail transit in China. As the hub facility of the subway system, underground subway station is a highly populated public place with narrow space, which can easily cause serious casualties and property losses in fire accidents. Given the current situation of severe fire risk in subway stations, it is urgent to carry out research in the cross field of fire smoke control and occupant evacuation, and explore integrated methods to improve the fire risk control ability of subway stations.On the other hand, the Ministry of Housing and Urban-Rural Development continues to replace the mandatory provisions in current standards with the full-text mandatory construction specifications. With the revocation of mandatory provisions in standards related to subway fire protection after the promulgation of the new national standards, the autonomy in the fire protection design practice is expanded. Therefore, there is an urgent need for scientific and quantitative evaluation and optimization methods for fire protection design in subway stations. Focusing on the protection of fire evacuation safety, this work carries out research from three aspects including subway station smoke spread prediction theory, fire risk evaluation method, and fire risk control optimization method. The main research contents are as follows:In the aspect of horizontal smoke spread prediction on the same floor of subway stations, a ceiling temperature rise exponential attenuation model with obstacle correction is established. The calculation method of wake area length formed by smoke layer flowing through the obstacle is established. In the aspect of vertical cross-floor smoke spread prediction in subway stations, the temporal and spatial distribution of the airflow field is studied. In the opening at the top of the stair, a prediction model of the airflow velocity distribution on the central axis is proposed, and a prediction model of the critical ventilation volume for full smoke control is established with the virtual fire source method.In the aspect of crowd evacuation risk evaluation method in subway stations, the evacuation risk evaluation parameter system, which includes multiple evaluation dimensions, is proposed with corresponding convergence analysis method. The non-dimensional superposition of all risk parameters is realized with the defined evacuation risk index. The risk evaluation results in a real subway station show that the long waiting time at bottleneck facilities such as stairs and turnstiles is an important source of evacuation risk.In the aspect of fire environmental exposure risk evaluation method in subway stations, the concept of fire risk index based on effective dose is proposed to characterize the fire risk level in an area. Combined with the occupant distribution in the evacuation process as the weight of each area, the risk evaluation of coupled human evacuation process and smoke spread process is realized. The risk evaluation results in real subway station show that the area with a long evacuation process and severe smoke accumulation has the highest fire risk level.In the aspect of evacuation facility layout optimization method, an adaptive queuing network model is constructed for efficient and reliable evacuation simulation, and a facility layout optimization iterative algorithm based on heuristic retrieval is established. The evacuation risk index can be significantly reduced after slightly adjusting the location of facilities according to the acquired optimal facility layout.In the aspect of ventilation system layout optimization method, a ventilation performance evaluation parameter system is established, and the optimization process of smoke exhaust vent layout is constructed. Through the comprehensive evaluation of ventilation performance, smoke control effect, and fire risk distribution, the optimal direction, size, and interval of smoke exhaust vents are acquired.
