Influence of the slope in the ventilation semi-transversal system of an urban tunnel

The covering of a section of the Inner Belt roadway (“Ronda del Mig”) in Barcelona gives rise to an urban tunnel of great length (1535 m). The tunnel is divided into two independent parallel galleries and its orientation is North–South, with a 2% upward slope towards the North. Although normal ventilation is achieved with jet fans, between the two galleries there is an interior passage for smoke extraction, in case of fire, through exhaust openings on both sides of this passage. Therefore, the tunnel has a semi-transversal ventilation system for fire incidents.The behavior of the smoke generated during those possible fire incidents in the traffic galleries was simulated with a commercial code, FLUENT^®, which allows a three-dimensional multispecies Navier–Stokes unsteady simulation. The mesh of each tunnel was made with about 250,000 triangular base prismatic cells. The simulated fire had a thermal power of 30 MW and the time step was set to one second, while the simulation covered 15 min.Special emphasis was put on the influence of the tunnel slope on the smoke’s behavior in each gallery. Simulation results showed that the fans’ capacity established in the project specifications was not enough to extract the smoke of a fire with the simulated power. A significant percentage of the smoke was aspirated through the exhaust openings but the rest continued rising to the tunnel portal due to the slope. This created a great risk mainly in the descending gallery with opposite traffic direction. For a more efficient extraction it was determined that the exhaust sections should be opened upward of the fire’s location. The standard opening, at both sides of the fire, reduced the capacity to extract smoke due to clean air aspiration from the lower portal.     

安全监控系统在齐岳山隧道中的运用

结合齐岳山隧道安全监控系统运用情况,简要阐述了美电贝尔监控系统的原理、组成和主要设备的作用性能,根据齐岳山隧道的环境特点,对安全监控系统设备的选择、配置和布设进行了详细介绍,指出了采用安全监控系统有效地解决了安全事故的发生,取得了良好的监控效果。     

某机场10kV变电站综合自动化系统的优化升级

介绍厦门机场10kV变电站综合自动化系统应用的几个发展阶段及升级改造,对系统在使用过程中所暴露出的缺陷进行分析、改进、优化。     

硫酸盐结晶作用后深埋公路隧道安全性能

对衬砌受盐结晶破坏后Ⅳ级围岩中埋深为30 m的隧道,运用同济曙光软件建立荷载—结构法拉压弹簧模型进行分析计算。计算表明:1)由盐结晶造成的隧道衬砌劣化,对病害处衬砌的力学性能影响较大,对无病害处衬砌的力学性能影响较小;2)无论是裂缝还是剥落病害,拱顶处的病害对隧道安全性的影响要比拱腰处的大,起拱线处的剥落病害对隧道安全性的影响也不容忽视;3)隧道衬砌同样位置发生剥落病害或裂缝病害时,剥落对隧道整体安全性的影响程度比裂缝大。     

水工长隧洞小断面开挖爆破施工技术

本文通过福州马尾白眉水库供水工程君竹至白眉黄厝村引水隧洞开挖爆破的施工,介绍了长距离小断面水工隧洞的开挖爆破施工技术,对洞内光面爆破、排气通风等方面都有创新,值得同类工程参考借鉴。     

黄河公轨合建隧道火灾人员疏散安全研究

以济南黄河公轨合建隧道为研究对象,分别对公路隧道和轨道交通发生火灾时,纵向疏散楼梯和横向疏散门的间距对人员疏散时间的影响进行分析,获得必需疏散时间.结果表明:疏散楼梯间距为60 m和75 m时,均满足安全疏散要求;轨道交通发生火灾,在通风有效情况下,人员可用安全疏散时间TASET为2700 s;疏散门间距为150 m和...     

隧道交通安全研究综述

介绍了关于隧道中发生火灾的研究,交通事故发生机理,隧道交通安全问题防治研究等的现状,指出各类隧道交通安全研究中存在的问题,以期为后续的公路隧道安全研究提供参考。     

对既有废弃隧道再利用的探讨

以险峰隧道为工程背景,对既有废弃隧道再利用时的勘测、设计、施工方法等方面进行了阐述,提出了既有废弃隧道再利用的一些要点,以提高既有废弃隧道的利用率,充分发挥既有废弃隧道的经济价值和社会价值。     

浅谈隧道施工的安全管理

针对隧道工程施工的特殊性,从隧道施工的安全组织机构、施工管理体系和应急预案等方面进行了分析和论述,以便积累隧道施工企业管理经验,减少安全事故的发生,确保工程施工安全。     

城市下穿隧道消防安全探讨

通过对下穿隧道的火灾特点和原因进行分析，结合国内外隧道火灾的案例，从隧道结构的耐火极限、安全疏散、灭火设施设备、排烟与通风系统、火灾报警与通信设施、消防供电等方面，针对性地提出了对城市下穿隧道的防火设计以及消防管理的建议。     

某隧道岩溶地段施工安全技术措施

以某隧道施工为工程背景,介绍了该隧道岩溶地段施工工艺流程,对注浆堵水和溶洞处理技术措施进行了探讨,分析了岩溶地段施工安全注意事项,为隧道岩溶地段的安全施工积累了经验。     

地铁隧道安全监测信息系统的设计与开发

针对地铁施工监测数据的文件管理模式已满足不了大量监测数据快速分析和长期安全保存的要求,提出了建立地铁隧道的安全监测信息系统,并对系统功能结构、系统数据库设计、系统开发环境等方面进行了阐述,以保证地铁隧道的安全施工。     

关注隧道消防构筑和谐工程--关于公路隧道消防安全工作的探讨与思考

从介绍云南公路隧道的情况入手，引用国内外公路隧道火灾的典型案例，通过纵横比较和分析，探讨研究了公路隧道消防安全工作面临的形势和问题，并提出了防范措施与处置对策。     

地铁盾构隧道运营养护的质量安全评价体系

鉴于今后城市地铁盾构隧道管理养护问题的重要性,本文充分借鉴现有铁路隧道和公路隧道的管养技术方法,深入分析地铁盾构隧道的自身特点,结合隧道检测工程经验,对地铁盾构隧道结构的质量安全评价系统进行了分析,试图为早日建立运营地铁隧道的相关技术标准提出一些有益的见解。     

Effects of the solid curtains on natural ventilation performance in a subway tunnel

Solid curtains can be installed in subway tunnels for the promotion of air ventilation in ventilation ducts in association with the piston effect caused by a running train. With an aim to analyze the effects of solid curtains on duct ventilation performance in a subway tunnel, the current study adopts the tunnel and subway train geometries which are exactly the same as those in a previous model tunnel experiment, but newly incorporates two ventilation ducts connected vertically to the tunnel ceiling and two solid curtains placed at an upstream position of a duct near the tunnel inlet and at a downstream position of another duct near the tunnel outlet, respectively. A three-dimensional CFD model adopting the dynamic layering method for tracking the motion of a train, which was validated against the reported model tunnel experiment in a previous study, is employed to predict the train-induced unsteady airflows in the subway tunnel and in the ducts. The numerical results reveal that the duct ventilation performance in a subway tunnel strongly depends on the operation of the solid curtains. The suction mass flow of the air through the duct near the tunnel inlet and the exhaust mass flow of the air through the duct near the tunnel outlet are increased considerably in the case with the solid curtains in comparison with those in the case without the solid curtains.     

Effects of the ventilation duct arrangement and duct geometry on ventilation performance in a subway tunnel

This study has investigated numerically the effects of the ventilation duct number and duct geometry on duct ventilation performance in a subway tunnel. A three-dimensional numerical model using the dynamic layering method for the moving boundary of a train, which was validated against the model tunnel experimental data in a previous study, is adopted to simulate train-induced unsteady tunnel flows. For the tunnel and subway train geometries that are exactly the same as those used in the model tunnel experimental test, but with the ventilation ducts being connected to the tunnel ceiling, the three-dimensional tunnel flows are simulated numerically under five different ventilation duct numbers and two different duct geometries. The numerical results reveal that: (1) for a given total area of openings, the ventilation duct number has little influence on the total mass flow of the air sucked into the tunnel through the ventilation ducts while the total mass flow of the air pushed out of the tunnel through the ducts increases remarkably with the increase in the duct number; (2) with the increase of the distance between a specific ventilation duct and the tunnel inlet the suction mass flow through the duct decreases significantly while the exhaust mass flow through the duct increases greatly, i.e., the location of a specific duct has a strong impact on the total suction and exhaust mass flows through the ventilation duct; (3) as the linkage angle between the tunnel ceiling and the upstream side wall of a duct is changed from 90° to 45°, the size of the re-circulation area inside the duct is much reduced when the train approaches the duct and thus the amount of air pushed out of the duct is greatly increased (i.e. the exhaust effect through the duct is remarkably strengthened).     

铁路隧道施工安全监控系统应用

结合向家坝隧道安全监控系统运用情况,简要阐述了TSAQ-1铁路隧道安全监控系统的原理、组成和主要设备的作用性能,对安全监控系统现场应用进行了详细介绍,得出了采用安全监控系统有效地解决了安全事故的发生,取得了较好的监控效果。     

谈隧道施工中的安全管理要点

分析了隧道施工中的＂五个关键＂的控制要点,提出了从思想、施工、作业、组织及制度五个要点来抓隧道施工安全,有利于确保隧道施工安全平稳有序进行。     

邻近岩土工程条件下地铁隧道的保护标准研究

针对基坑、建筑与隧道的距离、基坑的尺寸、建筑的高低和其桩基长短这几个因素对地铁隧道的变形的影响大小各有不同,在此通过有限元参数模拟得出其中的控制因素,进而得出保护标准,以期为今后类似工程提供指导。