隧道坡度对烟气蔓延特性及临界风速影响研究
Study on the Influence of Tunnel Slopes on Smoke Spread Characteristics and Critical Velocity
王建 1于丽 2王雪 2刘媛 2陈勇良 1赵灵吟1
作者信息
- 1. 中国电建集团成都勘测设计研究院有限公司,成都 611130
- 2. 西南交通大学 土木工程学院,成都 610031;西南交通大学 极端环境岩土和隧道工程智能建养全国重点实验室,成都 610031
- 折叠
摘要
隧道长大纵坡产生的"烟囱效应"增加了火灾烟气控制难度.为研究隧道坡度对烟气蔓延规律的影响,采用理论分析和数值模拟相结合的方法,探明了隧道坡度对烟气蔓延特性的影响,建立了适用于有坡隧道的临界风速计算模型.结果表明:1)火源上游烟气长度减小的变化率大于火源下游烟气长度增长的变化率;2)拱顶较高一侧烟气的稳定流速与隧道坡度呈二次方增长关系;3)无坡度隧道与单面坡隧道内最高温度升温曲线变化趋势不同,隧道无坡度时,温度先迅速升高后趋于一条直线,当隧道存在坡度时,温度随时间变化先升高后降低,最后逐渐趋于平稳;4)距离火源30 m左右为隧道内横断面上可视度分布规律变化的临界距离,坡度越大,人眼特征高度2 m处最低可视度越高;5)提出了坡度隧道临界风速修正系数,建立了适用于有坡隧道的临界风速计算模型,给出了不同火灾规模的烟气控制措施.
Abstract
The"chimney effect"caused by the long longitudinal slope of the tunnel makes fire smoke control more difficult.To investigate the influence of tunnel gradient on the smoke spreading law,a combination of numerical simulation and theoretical analysis was used to investigate the influence of tunnel slope on smoke spreading,and a critical wind speed calculation model applicable to sloping tunnels was established.Research shows that:1)The lower slope of the smoke spread is more important than the higher side of the smoke propagation.2)The steady flow rate of the smoke on the higher side of the vault is quadratically related to the tunnel slope.3)The maximum temperature rise curves in the tunnel without slope and in the tunnel with one-side slope have different trends.The temperature first rises rapidly and then tends to be a straight line for no sloping tunnels.For sloping tunnels,the temperature first rises and then decreases with time,and finally tends to be stable gradually.4)About 30 m from the fire source is the critical distance for the change of the visibility distribution law in the tunnel cross-section.The greater the slope,the higher the minimum visibility at the characteristic height of 2 m.5)The critical velocity correction coefficient for sloping tunnels is proposed,and the critical velocity calculation model applicable to sloping tunnels is established.Smoke control measures for different fire sizes are given.
关键词
隧道坡度/公路隧道/数值模拟/烟气扩散/临界风速Key words
tunnel slope/road tunnel/numerical simulation/smoke spread/critical velocity引用本文复制引用
基金项目
中国国家铁路集团有限公司科技研究开发计划项目(2022KY08)
出版年
2024
NETL
NSTL
万方数据