英文篇名
Slope Stability and Engineering Characteristics of Rock Mass at the Boundary of Slate and Schist - Slope adjacent to the Motian- Xiama Section, South Cross Island Highway as an Example
作者
羅百喬、潘立慈、羅 偉、李紫彤、陳玟玲、王泰典、謝有忠
關鍵字
板岩、片岩、交界帶、邊坡崩塌型態、岩體工程特性、南橫公路
摘要
本文針對近年來南橫公路摩天下馬沿線之邊坡經常性崩塌路段,配合多時期遙測影像邊坡崩塌分佈篩選及查核邊坡失穩類型,再輔以路線地質測繪與岩體特性調查,進行板岩與片岩交界帶附近邊坡失穩與岩體工程特性的關係探討。研究成果顯示,大南澳片岩與板岩交界帶之岩體Q值低於兩側圍岩,岩體破碎,為邊坡岩體滑動、岩屑崩滑以及落石好發處,Q值評分因子中以????????????以及????????差異較明顯。而板岩層中,板岩、千枚岩及變質砂岩交界帶,其岩體工程特性變化一般不及褶皺出露處明顯;另,中視尺度褶皺軸部斷層、層間剪裂、密集裂隙等調適構造則造成岩體破碎,易成為岩屑崩滑、落石的發生源。片岩層中不連續面組之持續性不佳或呈波浪狀,填充物蝕變程度不高;中視尺度褶皺軸部與邊坡崩塌位置的關聯性不及板岩層。大比例尺路線地質圖以及褶皺各部岩體工程特性經詳細地質評估及採岩體評分法量化分級,有利於板岩與片岩交界帶邊坡穩定及大地工程等課題深入評估。
英文摘要
The slope adjacent to the section between Motian and Xiama of South Cross Island Highway has suffered frequent collapses. To investigate the relationship between slope instability and the engineering parameters of the rock masses at the boundary of slate formation and Dananao schist formation, interpretation of spatial distribution of collapses from multitemporal remote sensing images, examination of slope instability mechanism, surveying and mapping of route geology, and evaluation of engineering parameters of rock masses have been performed and reported in this article. The research outcomes indicate that the Q values of the rock masses at the boundary of slate and schist are lower than those of the surrounding rocks, resulting in a prone area of rock slides, detritus slides and rock fall. Among the six evaluation factors of the Q-value, the magnitudes corresponding to RQD and Jr for rock masses at the boundary are obviously different. In slate formation, including the junction of slate, phyllite and metasandstone, the change in engineering parameters of rock masses is typically not obvious unless a fold exists. The adaptive structures, such as axial faults, pre-existed shear and dense fractures near the axis of a mesoscale fold, cause rock fragmentations, which are often the source for rock detritus and rock fall. In schist formation, rock joints are typically discontinuous, rough, irregular, undulating, and with coating or thin filling of low alternation. Thecorrelation between the mesoscale fold axis and the locations where slopes collapse is weaker than that for slate formation. The large-scale geological map of the route and the detailed evaluation of the engineering characteristics of each part of the fold are conducive to the evaluation of the slope stability at the junction of the slate and the schist.