孟祥昌 李永冲 熊建龙 王凯

摘 要：为优化大断面公路瓦斯隧道掌子面的风筒空间布置参数，降低掌子面瓦斯聚集超限问题，以召瀘高速白兆瓦斯隧道为研究对象，通过数值模拟压入式风筒在不同附壁水平距离、垂直距离、风筒出口距掌子面的距离工况参数下的风流特性及瓦斯扩散，确定风筒合理的安装方式和布置层位。结果表明：风筒附壁平距和垂距分别为2.25m和4.5m时，掌子面附近工作区受涡流和回流作用较小，瓦斯质量分数低于0.1%;风筒出口距离掌子面的距离为25.6m工况下，在兼顾施工经济性和安全性的同时，掌子面瓦斯不易积聚，隧道中后部瓦斯质量分数低于0.071%。按照模拟结果得出的风筒合理布置参数在现场实际应用，对比结果显示两种情况下的速度和瓦斯质量分数变化规律基本吻合，充分说明了风筒空间布置参数的合理性，研究结果对大断面瓦斯隧道灾害防治具有一定的指导意义。

关键词：瓦斯隧道;风筒布置;合理层位;风流特性;瓦斯扩散

中图分类号：U453.5 文献标识码：A 文章编号：1001-5922（2021）05-0187-06

Study on the Effects of Spatial Layout Parameters of Large Section Tunnel Air Duct on Wind Flow and Gas Diffusion Law

Meng Xiangchang1， Li Yongchong2，3， Xiong Jianlong2，3， Wang Kai2，3

（1. Yunnan Yunling Expressway Engineering Consulting Co.， Ltd.， Kunming 650000， China;2.Sichuan Institute of Coal Field Geological Engineering Exploration and Design， Chengdu 610072， China;3.Sichuan Keyuan Coal Mine Gas Coal Bed Methane Engineering Research Center Co.， Ltd.， Chengdu 610072， China ）

Abstract：In order to optimize the space layout parameters of the tunnel face of the large-section highway gas tunnel and reduce the problem of gas accumulation overrun on the tunnel face， the Zhaolu high-speed white mega gas tunnel is taken as the research object. By numerically simulating the wind flow characteristics and gas diffusion under different operating conditions of the horizontal wall distance， vertical distance， and the distance between the outlet of the air cylinder and the tunnel face， the reasonable installation method and layout of the air cylinder are determined. The results show that the horizontal distance and vertical distance of the attached wall of the wind cylinder are 2.25m and 4.5m respectively. The working area near the tunnel face is less affected by eddy currents and backflow， and the gas mass fraction is less than 0.1%. The distance between the outlet of the air duct and the tunnel face is 25.6m， while considering the construction economy and safety， gas on the tunnel face is not easy to accumulate， and the gas mass fraction in the rear of the tunnel is less than 0.071%. According to the simulation results， the reasonable layout parameters of the air cylinder are actually applied in the field. The comparison results show that the speed and gas quality scores in both cases are basically consistent. It fully illustrates the rationality of the spatial layout parameters of the wind cylinder， and the research results have certain guiding significance for the disaster prevention of large-section gas tunnels.

Key words：gas tunnel; air duct layout; reasonable horizon; wind flow characteristics; gas diffusion

隨着我国公路建设事业的快速发展，隧道工程正逐渐向“大、深、长、群”的战略格局迈进[1]。然而，我国西南地区地质条件复杂，施工地质灾害随处可见，在经济性、技术可行性、选址等因素的制约下，公路隧道不可避免地会穿越赋存瓦斯的煤系和石油天然气地层，在这些特殊地层条件的隧道施工常会遭遇瓦斯爆炸等灾害事故，对隧道工程建设和施工人员、设备的安全构成极大威胁和挑战[2-4]。……