公路隧道火灾CO浓度的数值模拟

国内针对公路隧道发生火灾时CO浓度变化规律的研究还很少。文章以厦门莲花隧道为对象,用FLUENT软件对否．固墨垫下哆火赛归气滇动鉴强尊彳亍了三维棼傅模拟,并分析了隧道不同高度不同横断面的CO浓度分布,得出了结论。     

Innovative experimental reduced scale model of road tunnel equipped with realistic longitudinal ventilation system

Road tunnels require ventilation system for different reasons in order to provide a good level of safety and effectiveness in ordinary service and, in case of fire, to prevent the upstream smoke flow (back-layering phenomena). To evaluate the ventilation system, full scale experiments are more expensive both in terms of the costs and time, and the CFD model has high uncertainty without experimental validation. In this paper the authors have made and characterized experimentally a reduced scale impulsive jet fan in order to carry out a scaled longitudinal road tunnel subsection equipped with a realistic ventilation system. This innovative reduced scale model of road tunnel could give more relevant information such as phenomenology and performance of full-scale tunnel using suitable similarity rules. It could be useful to do parametrical studies or to focus on particular physical aspects (i.e. smoke pattern of thermal plume behavior with respect to usual experimental sections reported in literature). The innovative reduced scale model presented in this paper can provide a useful alternative method with respect to the full-scale experiments.Moreover, the authors have simulated numerically, by means the CFD commercial software FLUENT®, the scaled road tunnel and have compared experimental and numerical results in terms of axial velocity.     

公路隧道明洞结构计算方法

简单介绍了公路隧道明洞结构的建模方式和荷载组合工况及截面验算方法,并结合具体工程实例进行了计算和分析,得出了有益的结论,为工程设计提供了一定指导。     

Characteristics of smoke extraction by natural ventilation during a fire in a shallow urban road tunnel with roof openings

The characteristics of the spread of smoke were investigated for a fire occurring in a shallow urban road tunnel with roof openings in its ceiling. In this type of tunnel, the smoke produced by a fire is ventilated through the openings in the ceiling given the natural buoyancy of hot smoke. A fire experiment was conducted using a 1/12 scale model tunnel to ascertain whether natural ventilation via the roof openings was sufficient to maintain a safe evacuation environment for tunnel users. The distance from the fire to the tip position of the spreading smoke and the thickness of smoke layers along the ceiling were investigated by changing the heat release rate and using two types of median structure as experimental parameters. The two types of median structure dividing the tunnel into two road tubes were pillars and walls. It was clarified that the smoke spreading distance was constant and independent of the heat release rate of the fire under our experimental conditions. Moreover, it was confirmed that the thickness of the smoke layers in the tunnel thinned out quickly due to the natural ventilation.     

以某新区市政隧道为例谈隧道塌方处理及效果评价

以某新区市政隧道一处塌方的处理为例,针对该塌方事故具体情况提出了处理措施,并对处理效果进行了分析和归纳,通过现场监测数据证明塌方处理方案是可靠的,对类似围岩隧道的施工及塌方处理有一定的借鉴作用。     

某公路隧道塌方处理

以某二级路隧道塌方为例,通过了解塌方的现场情况,对塌方的原因进行了分析,探讨了塌方的处理措施,并对具体的操作步骤作了说明,提出了隧道施工中易发生塌方的地形地貌、塌方时的处理时机及支护方法,以供借鉴。     

关于公路隧道照明的一些浅见

简单介绍了公路隧道照明的特点,指出了当前运营中公路隧道照明普遍存在的问题,并提出了自己的看法,对公路隧道照明下步的发展进行了预想,以期提高照明效果,保证行车的安全性和舒适性。     

公路隧道火灾的数值模拟

应用火灾动力学模拟软件FDS对某公路隧道内的火灾过程进行了数值模拟，定量预测了不同工况条件下隧道内的烟气流动状况及温度分布，并在此基础上对隧道通风方式、耐火性能，以及火灾探测报警中的温度点漂移问题进行了讨论。     

公路隧道围岩变形监测与分析

结合工程实例,通过对财神梁隧道全断面法和台阶法两种不同开挖方法下典型断面的围岩变形监测,研究了其稳定性状况,并对围岩变形曲线进行了回归分析,从而优化开挖方法和指导施工.     

浅析公路隧道结构设计体会

阐述了对公路隧道结构设计的认识和体会,讲述了公路隧道在结构设计时的依据及隧道结构体系计算的常见形式,并对可能在公路隧道结构设计中出现的问题进行了浅析,以期从隧道工程的安全性、经济性、舒适性出发合理设计。     

城市隧道通风设计中CO污染防治的分析与控制

我国城市隧道的里程越来越长,给城市交通提供快捷、便利的同时,也带来了很多的问题。由于机动车排放造成的CO污染对环境以及身边的人产生了很大影响,所以在设计过程中要规范。应选取合适的方式来降低隧道内及CO的量,以保证健康。     

Damages of the Shaohuoping road tunnel near the epicentre

Numerous infrastructures including national roads, tunnels, etc. in Sichuan Province were damaged to various extents in China's Wenchuan earthquake in 2008. The Shaohuoping road tunnel, near the epicentre of the earthquake, was the typical damaged one. The damage modes of different parts of the Shaohuoping tunnel were summarised based on the spot investigation data. It was found that various damages involving cracking and spalling of concrete lining were observed on different parts of the tunnel. The earthquake damages of critical positions, portal section and body portion, were simulated and analysed by finite element numerical model proposed in this paper. Influences of vertical motion on seismic responses of the tunnel were also studied by means of the finite element simulation. The simulation responses were compared with the spot investigations of earthquake structural damages to different parts of the tunnel. The comparisons showed a good agreement, which indicated that, the damage mechanism of the tunnel can be predicted reliably by the proposed finite element model. Furthermore, the results show that the damage of different parts of the tunnel is mainly controlled by horizontal ground motions, but the tunnel may suffer more damages with the effect of the vertical motion.     

城市隧道通风设计中CO污染防治的分析与控制

我国城市隧道的里程越来越长,给城市交通提供快捷、便利的同时,也带来了很多的问题。由于机动车排放造成的CO污染对环境以及身边的人产生了很大影响,所以在设计过程中要规范。应选取合适的方式来降低隧道内及CO的量,以保证健康。     

城市主干道下浅埋隧道设计

针对城市主干道下浅埋隧道的设计中存在的各种关键技术,以重庆轨道交通三号线二期工程经开园隧道为实例,提出相应的处理措施,采用全包防水,变形缝和施工缝采用双道复合防水,从而保证了止水效果。     

对公路隧道消防安全设计的探讨

介绍了公路隧道火灾的特点及危害,以六盘山隧道为例,讨论了公路隧道防火设计的方法,提出了对公路隧道消防设计的相关要求.     

城市地下公路隧道工程消防设计探讨

对城市地下隧道的耐火等级、人员安全疏散、防排烟、消防报警、灭火设施五个方面进行论述，概括了隧道消防设计中应注意的问题及解决方法，为解决实际问题提出了可供借鉴的意见。     

公路隧道渗漏水危害及预防措施

介绍了公路隧道渗漏水的危害,分析了公路隧道发生渗漏水的原因,并从提高复合衬砌防水夹层的完整性和密闭性、提高隧道接缝处的防水能力、提高衬砌自防水能力等方面提出了公路隧道渗漏的预防措施,以保证隧道的安全运营。     

Smoke spreading characteristics during a fire in a shallow urban road tunnel with roof openings under a longitudinal external wind blowing

A series of fire experiments was conducted using a 1:12 scale model of a shallow urban road tunnel with roof openings to clarify the flow structure of smoke and fresh air during a fire with a longitudinal external wind blowing above the roof openings. The model tunnel consisted of two road tubes separated by a pillar-type median structure. Five fire test cases were conducted by changing the heat release rate as the experimental parameter. When the smoke produced by a fire in the tunnel tube was exhausted by natural ventilation through the roof openings of the tunnel tube, fresh air was sucked in from the roof openings of the opposite tunnel tube. The flow of exhausted smoke and sucked-in fresh air created a complex three-dimensional flow structure inside the tunnel tubes. Stratified smoke that had formed under the ceiling of the tunnel tube was disturbed by the flow of sucked-in fresh air and was diffused on the upstream side of the fire. Compared to the condition without a longitudinal external wind, when a longitudinal external wind blew over the tunnel with the pillar median structure, the smoke spreading distance on the upstream side was longer than that without the external wind due to the diffusion of smoke. On the other hand, the smoke spreading distance on the downstream side of the fire was shorter than that without the external wind due to the improved smoke extraction performance by the Venturi effect of the longitudinal external wind. Furthermore, the smoke spreading distance on the downstream side was nearly constant and independent of the heat release rate of the fire, within the scope of our experimental conditions.     

浅谈公路隧道防水层施工中的注意事项

简述了公路隧道渗漏水,从施工方面分析了公路隧道渗漏水的原因,并针对性地提出了防水治理措施及防止公路隧道渗漏水的建议,以进一步完善操作工艺和管理制度,从而确保隧道整体不渗漏。     

Wind tunnel tests on heavy road vehicles: Cross wind induced loads—Part 2

The sensitivity of heavy road vehicle aerodynamic coefficients to different testing parameters (scenario, vehicle type and turbulence intensity) is experimentally evaluated in this paper through wind tunnel experiments. The first part of the paper has investigated the aerodynamic loads (both stationary and non-stationary) acting on a high-sided lorry (VAN) in a flat ground scenario. The mean aerodynamic coefficients, the flow pattern around the vehicle and the aerodynamic admittance function have been assessed and compared for different wind turbulence conditions (boundary layer simulations). The present paper instead investigates the influence of the infrastructure scenario (flat ground, embankment, single and double viaduct), of the exposition (upwind or downwind) and of a trailed unit on the aerodynamic loads acting on the vehicle. Moreover, the mean aerodynamic coefficients and the aerodynamic admittance function of the high-sided lorry considered in the first part are compared with the ones of other heavy vehicles (tank truck, tractor-semitrailer combination and tractor-trailer combination) to assess the influence of the vehicle geometry.