地铁隧道联络通道薄弱环节冻结孔布孔方式

Layout of Freezing Holes in Vulnerable Spot on Connecting Passage of Metro Tunnels

地铁隧道联络通道冻结施工的最薄弱环节为隧道开挖对侧顶部区域的冻结。目前,该区域的冻结存在单排长孔冻结和长孔加短排加强孔冻结两种布孔方式。通过对杭州、上海的3个不同布孔方式的地铁联络通道工程现场温度数据的收集,冻结、开挖期间冻结效果的观测,以及钻孔施工情况的分析与对比,发现采用短排加强孔的冻结效果有明显的提升,但是过度密集的布孔可能会造成断管问题的出现。

The freezing construction of the connecting pas- sage on the opposite tops of the frozen tunnel is the weakest link in metro tunnel engineering. At present, there are two main layout methods： the single platoon-hole freezing and the long freezing holes ＋ short reinforced holes. In order to select a better layout mode in the design and construction of freezing holes, the data of three different connecting passages in metro tunnels are collected. By comparing the temperature, freezing efficiency and drilling construction of the 3 modes, the layout of short reinforced freezing holes is selected, it is more efficient compared with the sin- gle platoon-hole freezing, but the excessive dense layout may cause cracks of the freezing holes.