垂直冻结法在大断面矩形顶管始发中的应用研究

Research on the Application of Vertical Freezing Method in Large-Scale Rectangle Jacking Pipe Launching

摘要: 本文针对上海某大断面矩形顶管隧道始发端紧邻市政综合管廊、高架桥且隧道底距微承压水层较近，复杂工况下仅水泥系加固无法有效控制洞门渗漏风险的难题，提出了采用垂直盐水冻结技术作为辅助止水措施，确保了顶管顺利始发。工程实践表明，结合强制解冻措施并合理规划局部垂直冻结范围及顶管始发流程，能够有效保证始发加固质量并规避顶管始发阶段刀盘及壳体被冻风险。局部冻结在既有水泥系加固中实施后呈现出后期冻胀融沉小的规律，表明垂直冻结辅助止水法为地质条件差、周边环境保护要求高的地下大断面顶管工程提供了一种新的解决途径。

Abstract: The paper indicates that shaft leakage risk cannot be controlled by slurry reinforcement in complex conditions, which exist in a large-scale rectangle jacking pipe launching in Shanghai that launched near the municipal utility tunnel and viaduct, even the tunnel bottom is very near to micro confined water layer. In this condition, the successful launching of the jacking pipe is ensured by finally adopting the vertical brine freezing technique as an auxiliary water stop measure. After practical exploration and verification, launching reinforcement quality can be ensured by properly planning partial vertical freezing and jacking pipe launching process, combined with forced thawing measures. Furthermore, it can reduce the risk of cutter head and shell freezing in the launching process. After partial freezing is implemented in the existing cement system, the law of frost heave and thawing subsidence in the later stage is small, indicating that the vertical freezing auxiliary method provides a new solution to large-scale underground pipe jacking with poor geological conditions and high protection requirement to the surrounding environment.