火灾工程在厦门翔安隧道项目中的应用

近年来,许多国家都发生了不同程度的公路隧道火灾事故,在国际上引起了广泛的关注。因此,火灾工程分析方法在国际隧道防火设计上的应用越来越普遍。通过引入可维生环境的设计概念,当隧道内发生火灾时,利用纵向通风模式达到满足隧道内人员疏散逃生要求的目的。厦门翔安隧道是国内第1条大断面海底隧道,全长约9 km,海底隧道长5.95 km。本文首先分析了厦门翔安隧道的特点,然后引入了国际上常用的进行火灾工程分析所使用的可维生环境概念,最后对该工程进行了火灾模拟分析。假定隧道内发生火灾的最大释热量为30 MW,分析后发现设计单位采用的2.5 m/s临界风速不能满足火灾工况下的烟控要求,烟气有回流现象发生。因此建议临界风速由2.5 m/s提高到3.0 m/s,确保烟气能被有效控制以保证隧道防火安全。在纵向风速为3.0 m/s的情况下,分析了火灾发展不同时刻的可维生环境参数,确保隧道内人员能安全疏散,从而提升厦门翔安隧道烟控、消防、防灾系统的整体设计水平。

Application of Fire Engineering in Xiamen Xiang'an Tunnel Project

To date,many tunnel fire accidents occur around the world and fire engineering is much common used in tunnel fire protection.Through the application of tenable environment concept,the aim is to let passenger successfully evacuate under the longitudinal ventilation when fire occurs.Xiamen Xiang'an tunnel is the first large cross-section tunnel beneath sea,the length is about 9 km and 5.95 km is under the sea.In this paper,the characteristics of Xiamen Xiang'an tunnel were firstly analyzed.And then the tenable environment concept was introduced.Finally,the fire simulation was employed to this project.With the assumption of maximal heat release rate(HRR) 30 MW in fire engineering simulation,it was found that the critical velocity 2.5 m/s that proposed by local design institute was not enough to prevent backflow of smoke when fire occurs.Therefore,it was concluded to increase the critical velocity from 2.5 m/s to 3.0 m/s to control fire smoke and ensure the safe environment for evacuation.Under the situation of critical velocity 3.0 m/s,the tenable environment parameters after fire occurrence were also presented in order to ensure safe evacuation.The significance of this work was to improve the fire protection design standard and tunnel safety level.