新庄线(市区段)潜盾隧道穿越台、高铁隧道既有结构下方之成功案例.pdf

42 99 捷運技術半年刊　第 期 新莊線（市區段）潛盾隧道穿越臺、高鐵隧道既有結構 下方之成功案例 1 2 摘　要 85*55 : Case Study of Tunneling Through a Retaining Wall Beneath an Existing Subway System for the Xinzhuang Line 1 2 Rong-Fong Jhan Dao-Hsin Cheng Abstract Tunneling between Songjiang Nanjing Station and Zhongxiao Xinsheng Station on the Taipei MRT Xinzhuang line was challenged by the need to drive through an underground structure containing six retaining wall panels, including irregular continuous walls and non-continuous foundation piles, beneath the existing tunnels of the Taiwan Railways Administration (TRA) and Taiwan High Speed Rail (THSR) system. As result of external environment limitations, a non-orthogonal approach was taken between the tunnel alignment and the retaining wall and foundation piles. For safety reasons, the construction procedure of this case adopted horizontal grouting to improve the soil condition around the retaining wall from the head of the Tunnel Boring Machine (TBM), and was coordinated with the glass- fiber shotcrete method and the well-point method to excavate and break up the obstacles and wall bodies through the air chamber with an only 85*55 cm channel to enter a very narrow working space at the front of the TBM. This article aims to describe the construction method and countermeasures adopted during this case, as well as the difficulties encountered during the period when TBM drove through the wall. Furthermore, it conducts a wide discussion of the dangerous conditions that occurre