台北捷運CN253B標潛盾隧道穿越北門古蹟下方之保護措施

北門為國家一級古蹟，台北捷運南港線CN253B標連接中華路及忠孝西路二重要交通路段，於此道路下方構築潛盾隧道而穿越北門古蹟。此區域建物除北門外，亦包括高架橋匝道及民房。經過縝密之路線研選後，雖採最小之隧道曲率半徑設計，儘量避開北門以減少對該結構物影響，但仍不免侵入北門基礎下方70公分範圍。由於北門係一相當重要文化資產，細部設計階段即審慎進行最佳保護方案之規劃、研選與評估，決定採用高壓噴射灌漿（JSG）土壤改良法以阻隔潛盾施工對北門所可能引致之負面影響；並在施工階段依循設計考量重點妥善計劃各項施工細節及嚴密監控，克服施工期間不可預期的問題與地盤反應行為所造成之沉陷，文中將簡述施工過程所遭遇之問題及其因應對策。在潛盾上、下行隧道分別通過後，北門發生的累積最大沉陷量僅21mm，在嚴謹要求的安全標準範圍內，有此一成果誠屬不易，是台灣地區首次兼顧古蹟保護與施工建設之成功案例。

關鍵字

高壓噴射灌漿；建物保護；支撐系統；潛盾隧道

並列摘要

The North Gate is a class 1 national historical monument which is located around the intersection of Chung-hwa Road and Chung-hsiao west Road. Taipei MRT Nankang line construction contract CN253B was planned to go underneath the vicinity of North Gate. For preservation purpose, the shield tunnel construction method was used. The near by also includes elevated highway ramps and some private-owned buildings. With a careful alignment study, a minimum tunnel radius standard was chosen to minimize the impact to the North Gate and other near by structures. However, the shield tunnels pass area underneath 70cm of the North Gate foundation can not be avoided.Due to the importance of the North Gate, a building protection planning and evaluation study was conducted during the earlier detailed design stage. The JSG method of soil improvement was applied to isolate the negative impact from construction of shield tunnel method. During construction stage, the concept in design stage was implemented and settlement due to construction was controlled. This paper depicts the problems and solutions during construction. After the shield tunnels were completed, the cumulative maximum settlement of North Gate was less than 21mm and very small under the strict criteria. This is the first successful construction case which also took good care of historical monument.

並列關鍵字

jet grouting ； building protection ； shoring system ； shield tunnel

國際替代計量

台北捷運CN253B標潛盾隧道穿越北門古蹟下方之保護措施

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