台灣西南部泥岩區穩定泥岩斜坡之特徵研究

Characterization of the stable mudstone slopes in Foothills of Southwestern Taiwan

顏富士(Fu-Su Yen) ； 吳秋相(Chiu-Hsian Wu)

《鑛冶：中國鑛冶工程學會會刊》 40卷3期 (1996/09) Pp. 95-107

https://doi.org/10.30069/MM.199609_40(3).0011

摘要

本研究於台灣西南部泥岩地區擇定五種斜坡：包括起始裸化斜坡、開始綠化斜坡、及綠化又裸化斜坡，瞭解泥岩地區穩定斜坡之地形特徵，以探討加強泥岩斜坡穩定、阻止惡地擴大之基本條件。裸露發生之斜坡，顯然可依其傾角略分為兩大類：50~70°＞ 70°。其中前者最易發生裸露，後者裸露後仍有較高機會回綠。由於一般裸化發生後，其擴大先波及其上（高）方坡面再擴及下（低）方坡面。再加以高角度坡面的裸化由坡首引發，故以陡坡蓋頂工法保護坡頂，杜絕雨水侵蝕坡首，配合降低斜坡長度，是可穩定泥岩斜坡裸露。本研究結論已於計畫進行中（民國81年初起）付諸現場試驗，歷經三年觀察極具成效。並已正式運用於南部第二高速公路之施工設計。本研究也提出：在不超過8公尺相對高程及坡度小於50°下，常緣坡面之坡度與坡高關係略成H（高程）=30-1/2*A（坡角）超過此關係後，緣坡將有成裸坡之高機會。

關鍵字

泥岩 ； 惡地地形 ； 侵蝕作用 ； 斜坡穩定

並列摘要

Critical conditions for the formation of a stable slope in the mudstone area in Southwestern Taiwan were examined. Samples used in this study included: slopes of uncovering being initiated, nude slopes but vegetations being recovered, and nud slopes which are recovered obviously but removal of coverage is intiated again. Characteristics for the initiation of the removal of covering (vegitations) from a slope can be divided into two catagories: slopes with slope-angles ＞70° and 50~70°. The former possesses higher possibility to be recovered, while the latter may suffer nudeness which extends from the initial site upward to the slope's crown then downward to the toe. Slopes with high slope-angle (＞ 75°) and proper structures on the top of the slopes, which protect the crown from erosion, are suggested as the best way to stabilize the mudstone slopes in the area. Field tests which performed as the suggestion expected have been examined by a parallel test since 1992 till now. The relationships between green and nude for slopes with relief less than 8 meters and slope-angle ＜ 50° are also discussed.

並列關鍵字

Mudstone ； badland topography ； slope stability ； erosion