英文篇名
TREATMENT FOR THE COLLAPSE OF AN INCLINED TUNNEL THROUGH FAULT ZONES
作者
翁世樑、謝玉山
摘要
某壓力鋼管隧道呈48°傾斜,全長約424公尺,此隧道位於砂岩與粉砂岩地層中,施工期間分為上、下傾斜段同時進行。隧道斷面為57m2,開挖方法採爬昇機方式進行,即先挖掘一條小導坑約5.8m2。導坑貫通後,再由上往下進行全斷面的擴挖工作,並利用原導坑來卸碴。上傾斜段在擴挖時曾先後發生兩次嚴重的坍落。第一次係因地下水滲流引起斷層破碎帶的坍落,單是回填坍方空洞之混凝土即達l,544m3,全段42公尺計費時五個月才處理完畢。第二次則純為破碎地層引致之坍落,其規模較小,但坍方範圍則長達37公尺。兩次坍落災害均以加強支撐、回填灌漿等方法處理,惟因隧道傾斜較陡故施工較為困難。文中說明上述處理方法,並就既有之地質資料探討坍落行為與可能之預防措施。
英文摘要
The penstock tunnel discussed has an inclination of 48° and a length of 424m. With a crosssectional area of 57m2, the inclined tunnel was constructed in the upper and the lower part. The rocks encountered are sandstone and siltstone. At first, a pilot tunnel of 5.8 m2 was excavated by means of the raise climber. After completing the pilot tunnel, the enlargement was then undertaken downwards. In this case, mucking was done easily and quickly through the pilot tunnel. Two serious collapes had occurred during the enlargement of upper part. The first one was caused by seeping of ground water in fault zone. Only the cavity was filled with concrete of 1,544m3, and it took five months to pass the 42-meter collapsed tunnel. The second was due to the collapse of cataclastic fault material, which extended for 37m long. Grouting and strengthening support were applied to both the problematic sections; however, these were more difficult to do because of the steep inclination of the tunnel. In this article, the effective mentioned above were described, and the collapse behaviors and the feasible preventive measures were also discussed based on the existing geological data.