八达岭长城站大型地下洞室群施工期通风技术探究

Ventilation Techniques during Construction Phase of Ultralarge Underground Tunnel Groups of Badaling Great Wall Station

作为目前国内最复杂的暗挖洞室群车站工程,八达岭长城站具有多洞室、多工作面、通风网络复杂的特点。为解决车站施工期间通风散烟难题,在考虑洞室群风网结构动态变化的基础上,提出多阶段通风方案,依次为压入式通风、巷道式通风和混合式通风,并采用数值模拟方法研究了长距离独头掘进通风的合理性。同时,基于实测通风数据,通过理论计算和通风网络解算分析洞室群巷道式通风及混合式通风状态,明确风网结构变化对通风效果的影响。结果表明:1)多阶段通风设计能满足车站施工期间通风要求;2)独头掘进工作面爆破后通风30 min,空气中主要污染物质量浓度符合规范要求;3)通风网络解算结合通风质量监测,可有效指导通风系统优化,调整通风措施;4)局部导流风机和除尘设备的使用,显著改善了隧道交叉点及密集钻爆区域的空气质量。研究成果可有效解决地下车站通风网络动态变化难题,实现洞室群施工期间空气的高效置换。

As the most complicated mined underground cavern group project in China,the Badaling Great Wall station has the characteristics of multiple caverns and working faces,as well as a complicated ventilation network.For ventilation during the station construction,a multistage scheme of forced,gallery,and mixed ventilations is proposed considering the dynamic changes in the wind network structure of the cavern group,and a numerical simulation method is employed to study the rationality of the ventilation scheme of long dead-end heading.Subsequently,based on the measured data,the gallery and mixed ventilation status of the cavern group is analyzed using theoretical calculation and ventilation network solution results,and the influence of the wind-network structure variation on the ventilation effect is clarified.Results show that:(1)The multistage ventilation design can meet the ventilation requirement during the station construction.(2)After blasting,the concentration of main air pollutants can meet the specified requirements when the tunnel is ventilated for 30 min.(3)Ventilation quality monitoring and network solution methods can effectively optimize the ventilation system and adjust the ventilation measures.(4)Air quality at the intersection of the tunnels and densely drilling and blasting areas can be significantly improved after using local fan and dedust equipment.The results can solve the problem of dynamic ventilation in a large underground station and achieve efficient air circulation during construction.