越江盾构隧道排烟口设置位置对比研究

Comparative Study on the Setting Location of Smoke Exhaust Port of River Crossing Shield Tunnels

为了研究越江盾构隧道顶部排烟和侧壁排烟两种模式对火灾烟气的控制效果,运用CFD数值模拟的方法对比分析了两种模式对烟气层高、隧道拱顶温度、排烟口的排热速率和排热效率等指标的影响。结果表明:顶部排烟模式下烟气纵向蔓延速度要明显更慢;侧壁排烟模式对向下游蔓延的烟气控制效果较差,烟气层高和拱顶温度在火源两侧呈近似对称分布。在排烟效率方面,顶部排烟模式效果相对较高,比侧壁排烟模式高出9%。综合来讲,顶部排烟模式对烟气的控制效果更好,因此从烟气防治的角度来讲盾构隧道排烟设计应优先考虑顶部排烟方式。

In order to study and analyze the control effect of two modes of smoke exhausting and sidewall smoke exhausting at the top of the river crossing shield tunnel,the effects of the two modes on the parameters of high smoke layer,tunnel vault temperature,exhaust heat exhaust rate and heat removal efficiency were compared and analyzed based on CFD method.Results show that the rate of longitudinal smoke propagation is apparently slower in the case of top extraction.The side extraction mode showed weaker performance to prevent downstream smoke propagation,where the smoke layer thickness and the temperature under ceiling showed approximately symmetrical distribution on both sides of the fire.Top extraction also showed better performance in terms of the smoke exhaust efficiency,which was around 9%higher than that of side extraction.In general,the top exhaust mode has better control effect on the flue gas.Therefore,top extraction is suggested as a preferred design of smoke control in underwater shield tunnels.