地铁浅埋隧道双侧壁导坑法预留核心岩柱施工技术

为解决地铁暗挖大跨度双侧壁导坑法施工中,开挖断面较大,后续施工拆撑危险系数较大,二次衬砌模板支架搭设加固难度大的难题,以青岛地铁3号线太平角公园站-延安三路站区间存车线为例,采用预留核心岩柱、新旧施工技术方案对比方法,在施工过程中加强施工现场监控量测,并指导施工。主要结论如下:1)与常规双侧壁导坑法全部开挖完成后统一进行二次衬砌相比,拆撑工作量小,安全系数高,施工效率高;2)通过监测数据得知地表沉降变化值较小,对地表影响较小,适合城市地铁施工。

Case Study on Construction of Shallow Metro Tunnel by Double Side Heading Method with Core Rock Kept

The stabling siding section of the running tunnel from Taipingjiao Park Station to Yan’ansanlu Station on Line 3 of Qingdao Metro is a large cross section shallow tunnel to be constructed by double side heading method. If the conventional double side heading method is adopted, there is great risk in the support dismantling and it is difficult to erect the falsework for the secondary lining. Therefore, core rock is kept in the double side heading method. During the construction of the tunnel, monitoring is strengthened so as to provide guidance for the tunneling. In the end, the tunnel has been built successfully. Conclusions drawn are as follows: 1) Compared to the conventional double side heading method, the innovative double side heading method can reduce the quantity of the support to be dismantled, and can improve the safety coefficient and the construction efficiency; 2) The monitoring data show that the ground surface settlement induced can meet relevant requirements, which indicates that the innovative double side heading method is suitable for the construction of urban Metro works.