双护盾TBM步进过站路径研究

Research on the Routing Scheme of a Double Shield TBM Passing through the Metro Station

  • 摘要: 双护盾TBM因其施工安全、高效、快速的优点被广泛地应用于城市轨道交通建设中,合理的过站路径也是TBM隧道施工的关键技术之一。文章基于青岛地区双护盾TBM施工常用的设备型号及过站方式,深入研究、分析了不同机械过站方式、路径与限界之间的关系,并对小净距隧道进行施工风险评估,结论如下:(1)优先考虑整机曲线步进过站方式,过站路径为两段相切的等半径反转曲线,半径R=350 m工程性价比最高;(2)二次衬砌状态过站时,矿山法接引洞建筑限界相同,偏转路径随偏转半径的增大而增大;(3)初期支护状态下过站时,矿山法接引洞长度、建筑限界均随侧墙厚度的增大而减小,当侧墙厚度接近1.15 m时则应优先考虑整机直线步进过站的方式;(4)以TBM掘进常见的中风化及微风化地层为例,矿山法接引洞夹持中岩柱岩体塑性区尚未连通、水平收敛较小,小净距隧道施工风险可控,可策施工安全;(5)建议优先考虑二次衬砌状态下TBM过站的方式,严格控制主机在反转曲线步进时的姿态及方向,及时、合理地纠偏,保证机械进站时刀盘与结构之间的预留安全余量。

     

    Abstract: Double shield TBM has been widely used in urban rail transit projects for its advantages of safe, effi? cient and fast construction, and a reasonable routing for TBM passing through the station is also one of the key technologies for TBM tunnel construction. Based on the equipment models and station-crossing methods commonly used for double shield TBM construction in Qingdao, this paper conducts a thorough research and analysis on the different TBM station-crossing methods, the relationship between routes and construction clearances, furthermore assesses the construction risks for tunnels with small clear distance. The conclusions are drawn as follows: (1) the engineering cost performance is the highest when priority is given to the method of whole TBM machine curved passing through the station, and the crossing route is two section of reverse curves tangent to each other, with equal radius and the radius of R=350 m; (2) when the TBM passing through the station installed with the secondary lining, the construction clearance of the mined approach tunnel is the same, and the deflection route length increases with the increase of the deflection radius; (3) when the TBM passing through the station installed with the initial support, the length and construction clearance of the mined approach tunnel decrease with the increase of the sidewall thickness, and when the sidewall thickness is close to 1.15 m, priority should be given to the method of whole TBM machine straight passing through the station; (4) taking the common medium-weathered and slightly weathered strata in TBM tunnelling as examples, the plastic zone of the rock pillar sandwiched by the mined approach tunnels is not yet connected, and the horizontal convergence is small, so the construction risk of tunnels with small clear distance can be controlled, and the construction safety can be achieved; (5) it is recommended that priority be given to the method of TBM passing through the station install with the secondary lining, with strict control of the posture and direction of the TBM in the reverse curve section, timely and reasonable correction of the deflection, and ensuring the safety margin reserved between the cutter head and the structure.

     

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