3车道瓦斯隧道通风流场及瓦斯运移规律研究  

Ventilation Flow Field and Gas Transportation Law of Three-Lane Gas Tunnel

作　　者：陈治宇 杨枫 谢可 林国进 杨文波 何川[1] CHEN Zhiyu;YANG Feng;XIE Ke;LIN Guojin;YANG Wenbo;HE Chuan(School of Civil Engineering,Southwest of Jiaotong University,Chengdu 610031,Sichuan,China;Sichuan Highway Planning,Survey,Design,and Research Institute Co.,Ltd.,Chengdu 610041,Sichuan,China;Sichuan Chuanqian Expressway Co.,Ltd.,Luzhou 646500,Sichuan,China)

机构地区：[1]西南交通大学土木工程学院,四川成都610031 [2]四川省公路规划勘察设计研究院有限公司,四川成都610041 [3]四川川黔高速公路有限公司,四川泸州646500

出　　处：《隧道建设（中英文）》2024年第5期1029-1044,I0062-I0077,共32页Tunnel Construction

基　　金：国家自然科学基金(52378413);四川省杰出青年科技人才项目(2022JDJQ0018);四川省交通运输科技项目(2021-ZL-07)。

摘　　要：为有效进行大断面公路瓦斯隧道施工期通风降气,以古金高速公路大梁子隧道工程为依托,采用SCDM软件建立2台阶带仰拱的计算模型,使用Fluent软件进行数值模拟,揭示在不同台阶长度、风筒出风口距掌子面距离、双风筒布设形式下,隧道掌子面及附近区域的通风流场特征和瓦斯运移规律,并结合现场监测数据进行验证。研究结果表明:1)流场在通风20 min后基本稳定,上台阶和仰拱段会形成涡流阻碍瓦斯的运移、扩散和稀释,在风筒非对称布设情况下,掌子面风筒对侧的墙角处出现瓦斯积聚现象;2)隧道内通风降气效果的敏感性影响因素排序为双风筒及布设形式>风筒出风口距掌子面距离>台阶长度,建议优先采用双风筒同侧布设送风,其次调整风筒出风口距掌子面距离为20~25 m和台阶长度为15~20 m;3)采用双风筒同侧布设通风时,掌子面及附近区域风速提高、瓦斯体积分数大幅降低,且施工现场开展的送风试验与数值计算结果吻合度高,验证了双风筒同侧送风的可靠性。To perform the ventilation and gas reduction during the construction of large-section highway gas tunnels effectively,based on the Daliangzi tunnel of Gulin-Jinsha highway,the computational model of the two-bench excavation method with an inverted arch is developed by SCDM software,and numerical simulation is conducted based on Fluent software.The features of the ventilation flow and gas migration laws in the tunnel face and the neighboring areas under the different lengths of the bench,distance of the air duct outlet from the tunnel face,and the layout of the double air ducts on opposite sides and on the same side are disclosed and then validated using field monitoring data.Results reveal the following:(1)The flow field stabilizes after 20 min of ventilation,although vortices arise in the upper bench and the inverted arch,which hinders gas transport,diffusion,and dilution.With an asymmetric air duct placement,gas accumulates opposite the air duct at the tunnel face.(2)The ventilation sensitivity in the tunnel is influenced by the following:the double air duct and the layout form>adjusting the distance of wind pipe outlet from the tunnel face>adjusting the length of the bench.Prioritizing the use of the same-side layout for the air supply by the double air ducts,followed by adjusting the distance of the air duct outlet from the tunnel face by 20–25 m and the length of the bench by 15–20 m are recommended.(3)Ventilating the tunnel with double ducts on the same side increases the wind speed at the tunnel face and immediate areas,remarkably lowering the gas concentration.The results of the field air supply experiments agree with those of the numerical calculations,verifying the reliability of same-side double ducts for air supply.

关 键 词：3车道公路隧道 瓦斯隧道 大断面隧道 通风方式 双风筒布置形式 瓦斯运移规律 

分 类 号：U453.5[建筑科学—桥梁与隧道工程]