隧道施工压入式通风效果分析及参数优化研究

Effect Analysis and Parameter Optimization of Forced Ventilation during Tunneling

对隧道台阶法施工压入式通风效果进行分析并提出相关参数优化措施，利用流体力学软件Fluent，建立隧道三维模型并进行了数值模拟，分别对上台阶不同开挖长度及风管不同布设位置下流场特性的对比，分析了通风系统各参数对通风效果的影响。模拟结果表明：台阶的存在改变了射流发展一般性，射流主体提前收缩，有效射程减少；上台阶长度越短，射流有效射程越大，涡流区域覆盖范围越小；风管沿侧壁布设且管口至掌子面距离在5～10m时，通风效果最佳。

To analyze the effect of forced ventilation during tunnel construction by bench-cut method, and to put forward relevant measures of parameter optimization, a three-dimensional model of the tunnel was established and numerical simulation was carried out by means of fluid mechanics software Fluent. Meanwhile, the flow field characteristics were respectively compared with each other when there were different excavation lengths and different air pipe arrangement at the upper bench. And then the ventilation system＇s various parameters, which have influences on the ventilation result, were analyzed. The simulation results show that： （a） It is the existence of the benches that cause the change of the general pattern of jet flow development, that result in the contraction of main jet flow ahead of time, and that result in a decreasing of effective jet range. （b） The shorter the length of the upper bench is, the larger the effective jet range will be, and also the smaller the coverage range of eddy zone will be. （c） There will be the best ventilation effect if not only the air duct is placed along the side wall but also the distance from the pipe orifice to the working face is within the range of five to ten meters.