蘭台地區坡地崩塌演化與破壞機制分析

Landslide Evolution and Analysis of Failure Mechanism in LanTai Area

夏國強(Kuo-Chiang Hsia)

指導教授 ： 林美聆

國立臺灣大學/工學院/土木工程學研究所/碩士(2016年)

https://doi.org/10.6342/NTU201602999

摘要

臺灣地區由於山坡地面積佔全區70%以上，且常受颱風豪雨及地震之侵襲，大型坡地崩塌時常發生並造成災害。97 年辛樂克颱風之廬山地滑及98 年莫拉克颱風之高屏溪流域，均造成嚴重災害，故大型坡地崩塌災害潛勢及影響範圍分析實為重要研究課題。
宜專一線為宜蘭縣通往太平山森林遊樂區之重要觀光道路，其中蘭台苗圃往白嶺地區部分路段曾受到坡地崩塌之影響而損壞。根據前人文獻及既有資料，該區域之道路及擋土結構，皆經過多次修補，且現地調查時道路可觀察多處裂縫、植生傾斜及崩崖陷落等崩塌潛勢特徵。
本研究透過航照及衛星影像蒐集來判釋崩塌發生，並由現地調查之地表特徵可研判蘭台地區潛在崩塌及可能崩塌機制，同時配合多種監測系統及多時段影像輔助判釋，利用質點影像測速法 (PIV)來分析蘭台地區之地形演化，並藉由其他調查項目以及岩心箱取樣，研判研究區的地層位態以及進行材料性質試驗，利用PIV分析所得點資料的位移量以及位移方向，透過ArcGIS計算以及玫瑰圖統計來劃設研究區於各期影像中的可能滑動範圍以及主要滑動方向來決定分析剖面方向，配合鑽孔資料與孔內攝影成果建立潛勢區域之力學模型，在確認所分析剖面為最具代表性的分析剖面後，結合現地雨量及地下水位監測資料，以模擬方式分析崩塌潛勢區域之破壞機制以及滑動面。
研究結果發現，透過多時段影像可觀察到研究區在各期影像分析中主要崩塌推移位置、範圍以及主要滑動方向，而經過力學分析所得滑動弧位置與地表變遷分析有相對應趨勢，說明利用地表變位量所求得之可能發生破壞位置和力學分析所得滑動面於坡頂與坡趾位置相接近。

關鍵字

蘭台地區 ； 大規模崩塌 ； 質點影像測速法 ； 崩塌演化 ； 邊坡穩定

並列摘要

Due to slope land in Taiwan accounting for more than 70% of the region, the slope land often suffers typhoons and earthquakes induced landslides. For example, Typhoon Sinlaku caused the Lusan landslide in 2008, and landslides in Kaoping River Basin during Typhoon Morakot in 2009. Both caused severe damage, thus the potential and evolutions of large landslide become very important research topics.
The Yilan Special Route No.1 is the main road between Yilan City and Taipin Mountain Forest Recreation Area. According to previous study, the road pavement and retaining walls both went through many rounds of repairement, especially in Lantai area. In the field investigation, we could observe that there were many cracks on the road and trees inclined toward the dowm slope direction.
In this research, multi-stage aerial photos and the satellite images to determine landslide crown, and the results from field investigation were used to decide the potential scar and identified the failure criteria. The Particle Image Velocimetry (PIV) analysis was conducted for the terrain evolution in Lantai area, and results were referred to geological investigations and sampled the specimens from borehole cores, to determine the statue of ground formation and the laboratory tests were conducted. After transferring the point data from PIV analysis using ArcGIS and rosette statistics, the potential landslide area and the main sliding direction can be decided. Based on these results and borehole inclinometer results and drill reports, the model of potential landslide area could be established. This study combined the model with rainfall monitoring data in the field to back analyze the failure surface in each cases.
The results showed that by using multi-stage images we could observe the potential landslide scar’s position, range, main sliding direction and the evolution of landslide in each cases. The scar location matched the failure surface location well.
Key: Lantai area, Large-scale landslide, PIV analysis, Evolution of landslide, Stability of slope

並列關鍵字

Lantai area ； Large-scale landslide ； PIV analysis ； Evolution of landslide ； Stability of slope

參考文獻

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