台灣四面環海屬於山多平地少的島嶼國家,隨著人口數增加平地開發早已趨於飽和,現在更需與山爭地,每當雨季或颱風降雨豐沛時期,隨著地下水位上升使得邊坡穩定性下降進而引發邊坡沖刷破壞。 本研究以數值分析探討邊坡因降雨入滲導致破壞之機制。首先,建立非飽和土壤之固體力學方程式及滲流偏微分方程式,利用一系列案例驗證其可行性,並採用前人所做的砂箱垂直滲流試驗配合各學者所提出之水力傳導係數及網格之尺寸進行模擬比較其差異性。模擬邊坡模型降雨滲流試驗,觀察土壤內部之含水量、孔隙水壓力、正向應力及剪應力之分佈情形,並與前人所試驗結果進行比較,結果顯示與前人實驗之歷時分佈情形有相同趨勢。最後,探討不同土水特徵曲線與非飽和滲透係數對於邊坡降雨之影響
The abundant rainfalls brought by typhoons and during prolonged rainy season have often in the rapid rising of water table. As a result, shallow landslides have often encountered during or after these prolonged rainfall periods. In this study, the solid mechanics equations and seepage partial differential equation involved in the transient flow of water in unsaturated soil medium have been solved using a numerical tool. The study examined vertical seepage of sand box and rainfall percolation test of slope model. The numerical result was compared to the experimental data of water content, pore-water pressure, normal stress and shear stress. The effects of different soil-water characteristic curves and anisotropic hydraulic conductivity on the patterns were also examined