英文篇名
Difficulties and Countermeasures of Construction of New Ziqiang Tunnel Along Hualien-Taitung Railway Line
作者
黃鳳岡、李民政、李怡德、林敬智
關鍵字
沉泥層、中導坑工法、複合式灌漿
摘要
新自強隧道位於臺灣東部縱谷區。隧道全長2,667m,淨寬11.3m,為一單孔雙軌鐵路隧道,隧道貫穿舞鶴台地,沿線覆蓋10~95m。隧道沿途穿越崙山層板岩、舞鶴礫岩、玉里層片岩及十餘公尺厚之沉泥層,其中沉泥層為臺灣罕見之困難地質。本工程於2010年1月開工,隧道施工穿越沉泥層時發生嚴重抽坍、擠壓及湧水等問題,經採用中導坑開挖、開挖面預加固、複合式灌漿及微台階工法降挖等對策處理,成功突破300m長之沉泥層,終於2015年12月順利貫通。因穿越沉泥層地質之山岳隧道案例甚少,相關工程經驗彌足珍貴。本文將說明本隧道之困難遭遇與突破對策供後續工程參考。
英文摘要
New Ziqiang Tunnel is located in the East Rift Valley of Taiwan. The tunnel, which is 2,667 m in length and 11.3 m in width, is a single-tube double-track railway tunnel traversing the Wuhe Terrace. In general, the thickness of the overburden ranges from 10 m to 95 m. Besides, the tunnel passes through the LunShan Slate, Wuhe Conglomerate, YuLi Schist, and a silt layer with thickness of 10 m or more. The silt layer is known to be an extraordinarily poor stratum in Taiwan. The tunnel construction project began in January of 2010. Serious cave-ins, squeezing, and groundwater inflow were encountered when advancing the tunnel through the silt layer. By using countermeasures such as central pilot tunnel method, pre-reinforcement of tunnel heading, compound grouting and mini bench cut, the tunnel was successfully advanced through the 300-m long silt layer in December of 2015. The construction of New Ziqiang Tunnel is considered to be a valuable engineering experience as it is very rare for a tunnel to extend across a silty layer. In this paper, difficulties encountered during the construction of New Ziqiang Tunnel and countermeasures taken to overcome such difficulties are presented.