潛移深層地滑邊坡案例之變形特徵與運動歷程探討

Field investigation and associated numerical simulation on a deep-seated slope movement

張詠詠(Yung-Yung Chang)

指導教授 ： 王泰典

國立臺北科技大學/工程學院/資源工程研究所/碩士(2010年)

https://doi.org/10.6841/NTUT.2010.00411

摘要

邊坡崩塌破壞型態相當多樣化，主要受到現地地形、地質材料及地質構造等因素所影響。調查與界定潛在不穩定邊坡的範圍，評估、預測其穩定性與潛在的破壞型態，對於天然災害的防治而言極為重要。深層滑動屬邊坡崩塌類型之一，其特徵為邊坡滑移範圍龐大，短期間的滑移量值卻不明顯，一旦運動加速，極可能引發遽變式山崩。造成此類邊坡滑移的原因常非單一事件造成，而係長時間不同作用累積的結果。平時活動速度緩慢，地表無明顯變形特徵，查覺不易。目前對此類型崩塌的調查方式，以地質地貌調查、鑽孔取樣、變形監測為主，不僅費時費力，亦難以對滑動面位置做一明確的描述。
本研究以台灣東南部嘉寶地區新武呂溪旁一長期滑動之邊坡為例，調查並彙整地形學、地質學與運動學的資料，探討深層潛移邊坡之演化過程。地形學方面應用多期航照製作DTM比較地形與地貌的變化，辨識出多個邊坡滑動體的邊界與不同時期滑動的範圍。地質學方面進行地表地質調查，分析邊坡的材料特性與地質構造的影響，釐清以黑色片岩為坡體主要的組成材料，因片岩易沿片理折斷、剝落，形成地表水入滲的通路，造成岩體長期弱化的動力，並確認邊坡滑動範圍無重大斷層及大型褶皺軸通過。運動學分析方面彙整十餘年來邊坡滑移監測結果，地層滑移深入最大可達70 m，且滑移量最大位置符合1982年與2006年拍攝航照地形差異最大處的結果。最後依據地形學、地質學與運動學的比對結果，探討邊坡的結構束制、滑動體底部位置，並嘗試探討此邊坡之演化過程。

關鍵字

深層地滑 ； 潛移 ； 變形特徵 ； 運動歷程

並列摘要

The type of a landslide is very diversified and influenced by topography, properties of geo-materials and geological structural constraints. Identification of potential landside area, including type of possible movement and associated damaged ambit is one of the most important issues for modern natural hazard mitigation. Among the various landslide types, the deep-seated slope movement is the one characterized by a huge scope moving mass with a deep sliding surface, low displacement rate, or a connecting of several moving masses with deep sliding surfaces. As such, it is very difficult for field recognition and subsequent identification for the moving mass of a deep-seated slope, although some of its characteristics may be detected from aerial photographic image interpretation, which results in heavy going for hazard mitigation.
Focusing on a deep-seated slope movement case with 17 years monitoring data in southeast Taiwan, this article investigates the site characteristics of the slope. Firstly, digital terrain models, based on aerial photos taken in 1970’s, 1990’s, and 2008 are produced to grasp the variation of topography. The ambits of slope movements are recognized accordingly. Field investigations are carried out to discover the rock formation and geological structures, as well as to describe the geomorphologic characteristics. The mechanical properties of geo-materials are also estimated. A conceptual model associated with the kinematic future of the slope movement is established based on the investigation results accordingly, and following examined by the monitoring outcomes. Numerical simulation is then conducted to investigate the evolution of the slope movement. The influence of topographic-, material-, and structural factors on the development of a deep-seated slope movement are studied. Finally, distinct site characteristics related with various movement phases for a deep-seated slope movement are discussed and addressed.

並列關鍵字

Deep-seated slope ； creeping ； deformed characteristics ； deformational evolution

參考文獻

[10] 劉守恆，林慶偉， 「SPOT 衛星影像之崩塌地自動分類研究」，航測及遙測學刊，第九卷，第二期， 2004，9- 22 頁。

[6] 劉守恆，衛星影像於崩塌地自動分類組合之研究，碩士論文，國立成功大學資源工程學系，2002。

[4] Nemcok, A. Gravitational slope deformation in high mountains: Proc. 24th Int. Geol. Congr., Montreal, Sect., 13, 1972, 132-142.

[5] Radbruch-Hall, D. Gravitational creep of rock masses on slopes. In: B. Voight (Editor), Rockslides and Avalanches, 1. Natural Phenomena. Elsevier, Amsterdam, 1978, 607-657.

[12] Crippen, R. E.,“Measurements Of Subresolution Terrain Displacements Using SPOT Phanchromatic Imagery”,Episodes 15,1992,p.56-61