英文篇名
Difficulties and Challenges of New Wushanling Divert Water Tunnel
作者
周坤賢、陳正勳、周永川、蕭秋安、汪世輝
關鍵字
有害氣體、引水隧道、無岩栓設計
摘要
百年前嘉南大圳開工,帶來嘉南平原穀倉的富饒環境,舊烏山嶺引水隧道為嘉南大圳的關鍵工程,自通水啟用至今已超過90年,隧道結構已日漸劣化,為確保大嘉南地區有穩定水源,實有新建新烏山嶺引水隧道之必要。新烏山嶺引水隧道工程位於臺南市楠西區,曾文溪右岸曾文二號橋和曾文三號橋之間,亦即舊烏山嶺隧道東口堰下游側約80m處,完工後新舊烏山嶺引水隧道互為備援。新烏山嶺引水隧道已於2020年9月完工通水,2021年7月藉颱風豪雨進行排砂閘門有水試運轉。
隧道全長3,431公尺,內徑為5.4 m之馬蹄形隧道,隧道沿線由東至西分別通過鹽水坑頁岩、糖恩山砂岩、六重溪層及崁下寮層。經蒐集既設隧道施工期間於糖恩山砂岩地層中,有發生數次可燃性氣體滲出及氣爆意外事件,此外鄰近工程案例及鑽探調查成果及施工過程中皆發現,新烏山嶺引水隧道存在可燃性氣體湧出之風險。故本文將以此隧道及取水工程為例,說明具可燃性氣體地層中隧道之瓦斯氣體突出紀錄、地質調查、施工時安全管理及因應對策等,以作為
後續類似工程之參考。
影音導讀 https://youtu.be/EWWs9LOQHeY (請複製連結前往觀看)
英文摘要
The construction of the Chianan Irrigation started a hundred years ago, bringing the rich environment of the Chianan barn. The Wushanling water diversion tunnel is a key project of the Chianan Irrigation. It has been more than 90 years since the commencement of the water tunnel. The tunnel structure has been deteriorated day by day. In order to ensure a stable water
source in the Chianan area, it is necessary to build a new Wushanling water diversion tunnel. The new Wushanling water diversion tunnel project is located in Nanxi District, Tainan City, between the Zengwen No. 2 Bridge and Zengwen No. 3 Bridge on the right bank of Zengwen River. It is about 80m downstream of the east mouth of the existing Wushanling Tunnel. After
completion, the old and the new Wushanling water diversion tunnels will mutually intersect backup. The new Wushanling water diversion tunnel which was completed in September 2020, had a test run by way of heavy rain from typhoon in July 2021.
The tunnel is horseshoe-shape with a total length of 3,431 meters and an inner diameter of 5.4 m. It crossed the Tangenshan Sandstone at the construction stage. In the same stratum, there were several recorded gas explosions occurred in Wushanling tunnel. It means that this project is probably at the risk of gas burst during the construction. In addition, from
nearby engineering projects, drilling investigation results and construction process have revealed that the New Wushanling water diversion tunnel under the risk of gas exploring. Therefore, this article will take the tunnel and water intake project as an example to illustrate the geological survey of the tunnel in the flammable gas formation, the safety management during construction, and their countermeasures based on the gas outburst records. It is expected this stusy can be as a reference for subsequent similar projects.