广域降雨促崩模式之建置及应用!以高屏溪流域为例-中兴顾问社-财团.PDF

中華水土保持學報, 42(1): 1-11 (2011) 1 Journal of Chinese Soil and Water Conservation, 42 (1):1-11 (2011) 廣域降雨促崩模式之建置及應用-以高屏溪流域為例 陳建新 [1]* 譚志豪[1] 冀樹勇[1] 蘇泰維[2] 摘 要 本文採用定率法結合 GIS 技術，評估流域內各邊坡單元於特定降雨條件之穩定性 隨時間的變化關係，並探討各項水文與地質因子對降雨入滲引致岩屑崩滑行為之影響。本文採 用美國地質調查所發展之 TRIGRS 程式評估集水區內各邊坡單元之降雨促崩潛勢，並藉由邊坡 安全係數臨界值之觀念推得集水區內各區域之山崩臨界雨量門檻值。本文並以莫拉克颱風事件 為例，對高屏溪流域內特定聚落及交通要衝進行降雨誘發崩塌之潛勢評估，研判重要聚落或交 通要衝鄰近區域發生岩屑崩滑型山崩之潛勢等級以預作防範。相關成果可供後續防災、減災措 施以及保全策略擬訂之參考。 關鍵詞：山崩、定率法、臨界雨量。 An Application of GIS-Based Deterministic Model for Assessment of Regional Rainfall-Induced Landslide Potential-Example of Kao-Ping River Watershed Chien-Hsin Chen[1]* Chih-Hao Tan[1] Shu-Yeong Chi [1] Tai-Wei Su[2] ABSTRACT An effective assessment of regional rainfall-induced landslide potential using the GIS-based deterministic model is presented. This study adopts the Transient Rainfall Infiltration and Grid-based Slope-stability model (TRIGRS, developed by USGS) which couples an infinite-slope stability analysis with a one-dimensional analytical solution for rainfall infiltration to evaluate the regional landslide potential. Simultaneously, the rainfall threshold for each sub-watershed could also be obtained. The Typhoon Morakot event was taken as an example. The initiation locations of landslides for several dangerous villages and important transportation junctions in the mountain area of Kao-Ping River watershed are successfully predicted by the model and the spatial overlapping technique of GIS. The preliminary results can be regarded as good references for the scheming an early warning system in the future.