圖書典藏及影音數位平台

考量近年來集水區保育治理逐漸朝工程減量與非工程手段等方向邁進，因此治理工程地點之規劃與優先順序擬定實需要較審慎之評估，而非工程手段之土地管理由於牽涉國土復育與人民權益，更需要嚴謹之分析模式做為決策之工具，因此如何同時考慮降雨過程中土壤入滲、地表逕流與土壤飽和、未飽和孔隙壓力變化對坡地穩定之影響，建立高精度之降雨引發坡地崩塌模式，並據以探討不同降雨型態對水庫集水區坡地崩塌潛勢之影響，為本計畫研究目的。

As a result of the geological weakness in Taiwan, the landslides often occur during heavy rainfall. Consequences of landslides can be seriously silting reservoirs, mudslideing to destroy building and facilities, and escalating economic losses. Assessment on landslide potential in the watershed by heavy rainfalls has been successfully analyzed by the physical and numerical model. However, phenomena on landslides induced by the pressure in unsaturated porous media or the impact of rainfall-runoff process have not yet been appropriately predicated. This study is to establish a two-dimensional high-resolution model focused on rainfall-triggered unsaturated landslide in limited region with consideration on rainfall infiltration, surface runoff, and the variation of pore pressure in both saturated and unsaturated soil. The study will be fulfilled in three years. This report presents the progress results of the second year. By following the work content, the key of the study is focused on the development of two-dimensional rainfall-triggered unsaturated landslide model. The proposed model includes the submodels of overland flow, saturated and unsaturated infiltration, and landslides. By following the rerification of model verified, the influences of key parameters and rainfall patterns are then examined. The models is applied to study the occasions of landslides in Yufeng subcatchment of Shihmen Reservoir watershed; the slope failure area and depth simulated agree well with the compared results from DEM data. The uncertain factors associating with the evatuation of landslides potential were also examined. In addition, for those regions having the inconsistent results simulated by the present high-resolution model and that with 1-D concept, the in-situ test will be conducted to provide the in-depth data for the future study.