板岩區淺層崩塌滑動面曲率特性-以隘寮溪流域為例

本研究選以隘寮溪流域之莫拉克風災淺層崩塌案例為研究對象，主題為進行淺層崩塌滑動面之曲率，將不同之地形特性因子進行比較分析，淺層崩塌案例選以投影面積小於一公頃之崩塌地，共計210筆。利用GIS配合災前後數值地形模型作為產製及分析工具，針對淺層崩塌之滑動面，進行曲率與形狀因子研究。研究結果顯示，淺層崩塌面積小於1ha，多數集中於0.1~0.8ha之間，曲率介於0~0.005之間佔88%，曲率較小顯示崩塌面之半徑越大越平直。崩塌面縱軸長度多數集中於50~200m之間，縱軸長度越長其曲率越小半徑越大呈現正相關之趨勢。崩塌面橫軸寬度多數集中於30~80m之間，橫軸寬度其曲率與縱軸相比較橫軸半徑較小。崩塌區位位於山脊數量為29筆，曲率69%介於0~0.003之間；位於坡腹數量為73筆，曲率95%介於0~0.005之間；位於坡腳數量為108筆，曲率83%介於0~0.005之間，三種崩塌區位以位於坡腳崩塌筆數最多，顯示崩塌多位於坡腳。就坡度而言，崩塌地平均坡度82%集中於20°~40°之間，曲率主要分佈在0~0.005之間。崩塌地之災後-災前之曲率求其差異值災前曲率差異值大多分布於±0.005之間，而其中0~+0.005又較為多數，顯見災後曲率有變大之趨勢。

關鍵字

淺層崩塌；滑動面；滑動面曲率；滑動面深度；隘寮溪流域

並列摘要

The objective of study focuses on the slip surface curvature feature of shallow landslide in slate geological region of Ai-Liao River. The landslide inventory came from the shallow landslide induced by the heavy rainfall in 2009 Typhoon Morakot. The SL event of landslide area small 1 Ha and eliminating the toe failure type which eroded by debris flow and flash flood were selected. Finially, 210 cases were achieved within more 800 landslide inventories. DEMs of before and after event were used on GIS platform to achieve the SL feature factor of deminsion, curvature of failure surface, and et al. Results shows about 88% of all events, the area of SL with in 0.1 to 0.8 ha most, the curvature of failure surfaces are most within 0.00001~0.005. Small curvature means the SL failure surface to be more plane and straight. Next,the length of SL is most about 50 to 200 meter, The longer length, the small curvature is, this shows many shallow landslide sliped along the interface of debris soil and bed rock. More, the SL width concentrated in 30 to 80 meter, the transverse curvature is larger than longitudinal curvature. Many SL located in the slope foot, there are 83% in 108 events of curvature with in 0.0001 to 0.005. In the average grident of SL, 82% event concentrated in the degrees of 20 to 40 which the consist of the curvature from 0.0001 to 0.005. Last, the curvature variant has studied between before and after sliding, the result showed the curvature was increase after landslide in Ai-Liao River basin.