基于结构先行的浅埋碎裂岩体暗挖地铁隧道交叉点施工方案研究与应用

Research and Application of a Construction Scheme for a Bored Metro Tunnel Intersection in Shallow Fractured Surrounding Rock Based on the“Structure Priority”Principle

青岛地铁3号线中山公园站地处闹市区,采用浅埋暗挖法施工,施工难度大,工期控制严,安全等级高。文章针对地面车流量大、岩体碎裂、覆盖浅,车站主体与风道交叉洞室断面形状复杂、两侧临空面大、拐点易形成应力集中等特点,采用数值分析与现场监测结合的方法,研究了不同工况下的围岩应力变化和变形规律,提出了一种基于结构先行的浅埋碎裂岩体地铁隧道交叉点新施工方案。施工与研究结果表明:采用新施工方案,先施作隧道交叉洞室的圈梁和中间二次衬砌,形成框架结构,减小了大断面施工的跨度影响效应,有效控制了碎裂岩体的沉降变形,提高了施工速度,确保了交叉洞室的整体稳定。该施工方案尤其适用于薄覆盖碎裂岩体大断面交叉洞室,为同类工程建设提供了理论依据和实践经验。

Considering that the shallow-bored Zhongshan Park Station on Qingdao Metro line 3, which is locatedin a downtown area, is characterized by difficult construction, a tight schedule and a high safety level, and aiming atsome specific problems—such as large traffic flow on the ground, fractured surrounding rock, shallow overburden,complex section shape of the intersection between the station and air duct, a large free face on both sides and highpossibility of stress concentration at the corner point—this paper studies the stress and deformation of the surround-ing rock under different working conditions with numerical simulation and field monitoring. A construction schemeis proposed for the bored metro tunnel intersection in the shallow fractured rock based on the＂structure priority＂principle. The results show that adopting this new scheme, featuring the construction of a ring beam and middle sec-ondary lining for the intersection first and then forming a stable frame structure, can weaken the span effect of large-section construction, control the settlement of the fractured rock, improve the construction speed and ensure the sta-bility of the intersection, which is suitable for the construction of a large-section tunnel intersection in a shallowfractured rock mass.