https://scholars.lib.ntu.edu.tw/handle/123456789/40009
標題: | 森林集水區邊坡穩定性之評估:以蒙地卡羅模擬無限邊坡模式之參數 | 作者: | 黃誌川 徐美玲 |
關鍵字: | geographic information system;digital elevation models;Monte Carlo simulation;infinite slope model;地理資訊系統;數值地形高程模型;蒙地卡羅模擬;無限邊坡模式 | 公開日期: | 2003 | 出版社: | 臺北市:地理環境資源學系 | 起(迄)頁: | 1-18 | 來源出版物: | 地理學報 | 摘要: | Landslides have been the major concern of forest management in Taiwan since most part of the island consists of precipitous slopelands, which are composed of highly fractured geological formations. Mapping or delineating areas susceptible to landslides is essential for effective watershed management. Thus, this study aims to develop an effective method for allocating unstable slopelands. The process-based model uses GIS as an integration platform, and uses DEM to calculate slope gradient and specific catchment area for each grid, deriving NDVJ value from SPOT imagery. The model then uses Monte Carlo simulation to derive parameter values for cohesion and friction angle needed in the infinite slope model. Two simulation strategies are adopted. One treats the entire watershed as uniformity. The other uses NDVI to differentiate spatial variation of cohesion, and the friction angles of individual geological formation are simulated separately. The result shows that the accuracy rates of the two strategies in differentiating instable slopes are 64.0% and 76.4%, respectively. And the average rates for individual landslides being correctiy evaluated are 67.0% and 76.8% for the two respective strategies. In view of spatial distribution, most of the landslides in the Chi-Jia-Wan watershed are located in the EO formation (composed of quartzite, sandstone, slate, graphitic shale), while topographically, they are located in converging steep slopes. Landslides in the Yo-Sheng-Chi watershed mostly occurred along the river valley, and they were very likely to be triggered by human activities. Thus, the model performance was not as successful as in Chi-Jia-Wan watei shed. 臺灣地區山地遍佈、地質脆弱且地形陡峭,政府對於森林集水區的治山防洪工作一直不遺餘力,如何能有效地找出可能的山崩潛在危險區以利治山防洪工作的進行是本研究的卞要目的。本研究以GIS 為操作平臺,利用DEM 計算各網點坡度及比集水面積,並利用5 POT 衛星影像獲得常態化差異植生指標,以蒙地卡羅模擬無限邊坡模式所需的參數進行邊坡穩定性的評估;崩塌地的評估分兩種模擬方案進行分析,方案一將全區的植生和地質條件視為均質,方案兀利用NDvi 進行― :體與植生內聚力的加權,並根據地層分區進行內摩擦角的模擬。結果顯示,方案一與方案二對不穩定邊坡的評估正確率約為64.0%與76.4% ,推估成功率分別為670 %與768% ,相當有效。就崩塌地位置而言,七家灣溪集水區的崩塌地大多在EO (四稜砂岩、眉溪砂岩、白冷層)的區域高,區位上通常位於地形上有明顯匯流效應的陡坡上。 而有勝溪的崩塌地則多位於河谷地區,可能與該地區頻繁的人為活動有關。 |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/2006121215551272 | 其他識別: | 246246/2006121215551272 |
顯示於: | 地理環境資源學系 |
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116001847484846354713.pdf | 23.67 kB | Adobe PDF | 檢視/開啟 |
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