扇平林道崩塌地地層調查－電探方法的應用

扇平林道是聯絡林試所六龜分所與所轄扇平工作站的交通要道。由於地質地形條件欠佳，加之闢建時所採標準不高，維修經費不足，自民國六十五年在第一林班路段發生第一次崩塌，爾後在同一地點其狀況逐年惡化，更於78年9月再次發生大規模崩塌，路基崩失修復困難，遂有更改路線以避開崩塌地之議。本調查即針對崩塌發生的原因、往後可能動向，以及新路線的安全性等問題，進行研究。根據電氣探測調查結果，發現崩塌發生的主要原因，是由於地下水侵入了地層中的軟弱層，而形成淺層和深層的滑動面，其深度分佈在地表下1.5m、4.8m、8.6m以及20m、35m附近。在崩塌頭部下陷區有截水溝的存在，反而促使逕流集中入滲，需妥為處理。林道預定改道路徑，其安全性大抵上無問題，惟位於崩塌地上方的路段，長期而言，似屬於崩塌影響的範圍，須特別注意排水及棄土。全段新路線闢建後，應加強初期的護坡工程。崩塌地的處理原則，先求不使其惡化，注重上方的排水和土方穩定，俟有餘力可考慮下方溪流之整治和坡面的植生。

關鍵字

崩塌地；滑動層；電氣探測；大地比電阻

並列摘要

Shan-Ping logging road is a very important arrest connecting Lu-Kuei research storms sod Shan-ping work station. However, a severe landslide occurred in 1976 due to unstable geologic strata, concentrated rain fall, and insufficient road maintenance. From then on, it became worse especially during the typhoon season of every year. In September of 1989, this landslide moved downslope again and canard irrecoverable damage to the road. Eventially, it was derided to design a new path to prevent the reed from being destroyed frequently by landslide. The purposes of this investigation are attempting to find out the reasons of cornering landslide, forecast the develop-menial tendency in future, and discuss the safety of constructing the new path. According in analytical results of doctrinal inspection, the main footer of causing landslide is groundwater which seeps into weak strata. Groundwater had improved the formation of sliping layers beneath the ground surface. The depths of sliping layers are approximately in l.5m 4.8m 8.6m 20m and 35m from the surface. A diversion ditch located at stump head of landslide is stilt concentrating runoff and improving water seepage. It is a negative factor on stabilizing earth black, and has to be treated property. Comprehensively considering, there is sin problem with the safety of new path, however, drainage system and waste soil treatment is the section upon the upslope of landslide are two vital paints Se be particularly emphasized. In brief, tire nape protection measurements ought to be completed accompaning with the excavation of new path to reduce landslide. Besides, river consolidation and slope revegetation will make this landslide more stable, but it costs too much budget. After all, to drain runoff out of landslide area and stabilize the soil block is the principle of controlling landslide in the first stage.

並列關鍵字

Landslide ； sliping layer ； electrical inspection ； earth specific resistance

國際替代計量

扇平林道崩塌地地層調查－電探方法的應用

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