明挖隧道上跨地铁区间抗浮管幕保护方案研究

Study on Anti-floating Pipe Curtain Protection Scheme of Open-cut Municipal Tunnels Over-passing Existing Metro Tunnel

文章依托无锡市某道路快速化市政隧道上跨运营地铁区间盾构隧道工程,针对如何采用可靠措施有效控制基坑开挖施工对地铁的影响进行研究。采用抗浮管幕减小地铁区间上方基坑开挖卸载后土体及盾构隧道上浮,利用管幕与MJS加固体对明挖基坑底下方富水砂层进行封底处理以抵抗承压水,保护运营地铁安全。通过数值分析,合理确定工作井、管幕及MJS加固主要参数与地铁的关系,验证方案的安全性与合理性。

In this paper, based on the project of a high-speed municipal tunnel over-passing an existing metro tunnel in Wuxi City, the authors study how to use reliable measures to effectively control the impact of foundation pit excavation on the subway. The anti-floating pipe curtain is used to reduce the soil mass and shield tunnel floating after the excavation and unloading of the foundation pit above the subway section. The pipe curtain and MJS formation reinforcement are used to seal the water rich sand layer below the open excavation foundation pit bottom to resist the confined water and protect the safety of the subway operation.Through numerical analysis, the main parameters of working well, pipe curtain and MJS reinforcement and their relationship with the subway are reasonably determined to verify the safety and rationality of the scheme.