紧邻地铁隧道深基坑支护技术及监测分析

为确保既有轨道交通线路的正常运营，必须严格控制轨道交通线路周围施工对运营线路的影响。以广州市某运营地铁隧道侧方深基坑工程为背景，对深基坑紧邻地铁隧道侧的支护设计、施工方案及地铁隧道变形监测结果进行分析总结。主要得出以下结论： 1）需严格控制紧邻地铁隧道侧深基坑的施工，选择合理的基坑支护设计和施工方案对地铁隧道的结构安全至关重要； 2）紧邻地铁隧道侧分段施工，部分区段采用双排桩加直撑的支护形式，在提高支护刚度的同时方便基坑开挖，且施工时预留土台，可有效控制双排桩的变形，降低对地铁隧道的影响； 3）通过变形监测分析，地铁隧道变形满足规范要求，同时能确保基坑的安全。

Support Technologies for and Monitoring Analysis on Deep Foundation Pit Adjacent to Existing Metro Tunnel

The influence on the operating Metro lines induced by the construction of adjacent foundation pits should be strictly controlled so as to ensure the safety of the existing Metro lines. The support design and construction program of the deep foundation pit and the deformation monitoring results of the existing Metro tunnel are analyzed and summarized, with the construction of a deep foundation pit adjacent to an existing Metro tunnel in Guangzhou as an example. Conclusions drawn are as follows: 1) The construction of the deep foundation pit adjacent to the existing Metro tunnel should be strictly controlled. Rational support design and construction program of the deep foundation pit are fundamental for the structural safety of the existing Metro tunnel. 2) Section by section construction method is adopted for the foundation pit. Support consisting of double row piles and bracing is adopted for some sections of the foundation pit, which not only improves the rigidity of the support, but also is convenient for the cutting of the foundation pit. Soil bench is kept during the cutting of the foundation pit, which can effectively control the deformation of the double row piles and in the end can minimize the influence on the existing Metro tunnel. 3) The analysis on the deformation monitoring results shows that the deformation of the existing Metro tunnel meets the requirements of relevant standards and that the safety of the foundation pit is guaranteed. 