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 cause serious silting in reservoirs, mud or debris flow to destroy building and facilities, and therefore escalate economic losses. Assessment on landslide potential in the watershed by heavy rainfalls has been successfully analyzed by several physical and numerical studies. However, phenomena on landslides induced by the pressure in unsaturated porous media or the impact of rainfall-runoff process have not yet been appropriately explored. 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 model proposed several sub-models, including overland flow, saturated and unsaturated infiltration and landslides. The overland flow model is established based on the one-dimension kinematic equation. The saturated and unsaturated infiltration groundwater flow can be simulated by solving two dimension Richards’ equation, and the landslide potential will be analyzed by Bishop slope analysis method. After the influence of parameters and rainfall characteristics are examined, the developed model is then verified by in-situ testing data. Furthermore the developed model is used to examine the influence of rain pattern, then simulate the landslide potential under the conditions with various accumulated rainfall. And even the model is applied to Shihmen reservoir watershed to assess the influence of slope improvement measures. By following the assessment results, one can properly justify whether the structure or non-structure measures should be undertaken.