“先隧后站”区间与车站接口环梁施工技术

Construction Technology of Ring Beam Connecting "Tunnel Before Station" Section and Station

对于施工中出现的“先隧后站”工况,区间盾构隧道与车站接口环梁或位于内衬墙、或超出内衬墙,需要拆除部分管片并外扩围岩,存在安全风险并施工困难。针对地铁重庆西站接口环梁施工存在的问题,采用将外露管片预留200 mm长伸入内衬墙,其余使用线切割锯切除,环梁与内衬墙一体现浇的施工方案。介绍了管片切割、吊离及内部支撑搭设、环梁浇筑的关键施工技术。采用切除后与内衬墙同时现浇法施工环梁,施工后接口位置未发生明显的渗漏水,且安全可控、效益明显。

For the "constructing tunnel before station" condition during construction, the ring beams connecting the interval shield tunnel and the station are either in the lining wall or exceeding the lining wall, which require partial removal of segments and expansion of the surrounding rocks, leading to the security risks and construction difficulties. Tackling the existing problems in constructing the ring beams at Chongqing West Metro Station, the paper proposes a construction technic that preserves and extends 200 mm exposed segments into the lining wall, while the rest parts are been wired cut by the wire-electrode cutting machine, and the ring beam and the lining wall are poured together. In the paper, it introduces the key technics of the cutting and lifting of segment, as well as the internal support erection, and ring beam pouring. By pouring the ring beam and the lining wall at the same time after cutting the segments, the water leakage at the interface after construction is trivial, as well as with controllable security risk and remarkable profits.