人工冻结法在圆砾地层地铁联络通道施工中的应用

Application of Artificial Freezing Method in Construction of Metro Cross Passage in Gravel Stratum

  • 摘要: 南宁地铁3号线金琅区间联络通道所处地层主要为圆砾,其自稳能力差,易发生涌水冒砂、围岩扰动过大而使隧道变形的情况,设计采用人工冻结法施工。文章详细介绍了冻结过程中冻结孔布设、冻结参数选取以及土体在自然解冻后的融沉控制注浆参数优化等工艺。在积极冻结施工过程着重对盐水去回路温度、土体温度、泄压孔孔压进行分析,总结出土体温度变化、冻结壁形成的规律,准确判断通道开挖的时机,并针对联络通道冻结施工存在的问题提出了具体的对策措施。人工冻结法在该区间隧道富水圆砾层中的成功应用,可为其它类似工程提供参考。

     

    Abstract: The cross passages of Jinlang running tunnel section of Nanning metro line 3 are mainly located in round gravel stratum which is characterized by poor self-stability, sand gushing, water inflow and deformation caused by large rock disturbance. In view of this, the artificial freezing method is designed for construction of cross passages. The arrangement of freezing holes, selection of freezing parameters and optimization of grouting parameters to control of settlement of soil mass after thawing is described in detail. The temperature of circulated salt water,temperature of soil mass and pore pressure of pressure relief holes are specially analyzed during construction of active freezing, the rules of temperature change of soil mass and formation of frozen wall are summarized, the excavation time of cross passage is accurately judged, and the countermeasures for the problems in freezing construction of cross passage are proposed.

     

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