盾构隧道穿越人行天桥桩基的变形控制技术研究

Study on Pile Foundation Settlement and Construction Control Technology of Shield Tunnel crossing Pedestrian Bridge

为解决盾构穿越自稳能力差地层桥桩沉降控制困难的问题,依托盐田路站—北山道站区间穿越双拥公园人行天桥的工程实例,结合数值分析与现场沉降监测,分析了盾构下穿人行天桥桩基沉降变形特征,提出了针对性的施工控制技术。研究结果表明:盾构开挖面距桥桩-10~10 m (-1.5D~1.5D)掘进期间,对下穿桥桩影响最大,7号桥桩沉降3.10 mm,占桥桩最大累计沉降量的83%,8号桥桩沉降3.90 mm,占桥桩最大累计沉降量的77%。盾构开挖面距桥桩-6~6 m (-1.0D~1.0D)掘进期间,对侧穿桥桩影响最大,9号桥桩沉降1.82 mm,占桥桩最大累计沉降量的58%。提出的地表注浆联合洞内注浆加固和盾构控制掘进的方式确保了人行天桥整体结构的安全与稳定性,可为今后类似工程提供借鉴与参考。

Based on the engineering example of crossing Shuangyong Park pedestrian bridge between Yantian Road station and Beishan Road Station,combined with numerical analysis and site settlement monitoring,this paper analyzes the settlement deformation characteristics of the pile foundation of the pedestrian bridge under shield tunneling,and puts forward the targeted construction control technology.The results show that during the excavation distance between shield excavation surface and bridge pile-10~10 m(-1.5D~1.5D),the influence on underpassing bridge pile is the greatest.The settlement of No.7 bridge pile is 3.10 mm,accounting for 83%of the maximum cumulative settlement of bridge pile,and that of No.8 bridge pile is 3.90 mm,accounting for 77%of the maximum cumulative settlement of bridge pile.During the tunneling period between shield excavation surface and bridge pile-6~6 m(-1.0D~1.0D),it has the greatest influence on the side crossing bridge pile,and the settlement of No.9 bridge pile is 1.82 mm,accounting for 58%of the maximum cumulative settlement of bridge pile.The method of surface grouting combined with grouting reinforcement in the tunnel and shield controlled tunneling ensures the safety and stability of the overall structure of the pedestrian bridge.The research results can provide reference for the construction of similar projects in the future.