中文摘要：

针对长大隧道提出一种分段水喷雾方法对隧道进行保护,即每隔350m左右设置一小段喷雾系统,火灾时开启对应区段两端的喷雾系统,利用喷雾区段的过滤作用阻止烟气向上下游扩散,保证区段外环境的相对安全,从而有利于人员逃生.利用10∶1模型试验和实体隧道火灾实验证明水喷雾段可以有效降低隧道温度,阻止烟气及热量向下游传播,水喷雾压力越大喷雾粒径越小,越有利于隧道降温作用,对隧道分区防护作用越明显;分段水喷雾流量和喷头不同布置对阻止烟气向下游扩散作用不明显,通风虽然会削弱水喷雾段对烟气扩散的阻止作用,但不妨碍其在隧道中的应用.

英文摘要：

A water mist segment system is proposed to apply to protect tunnel. The small water mist seg- ment is installed at each 350 meters in tunnel; and the two segments at the top of fire zone would be opened when the fire happen. The water mist will prevent the smoke spread to the downstream of tunnel because of the filter of water mist; therefore, it can provide people for evacuation in a relative safe environ- ment. The 10 ： 1 scale model experiments and real tunnel fire experiments were carried to test the effec- tiveness of water mist segment on smoke blocking and reducing temperature. The results show that the water mist segment can effectively prevent smoke spreading to downstream and reduce heat flux. Nozzles with higher water pressure produce smaller size water droplets which can enhance cooling effect in tunnel. Different water flow rates and nozzle arrangements have less impact on preventing fire spread. Ventilation system weakens the effectiveness of smoke blocking caused by water mist segment, but water mist seg- ment is still useful for fire safety in tunnel.