[[alternative]]Using Finite Element Method on the Stability Analysis of Rainfall-Induced Deep-seated Landslide Triggered by Typhoon Sinlaku

[[abstract]] 地滑帶來危險的地質災害，除導致生命損失外，也會破壞基礎設施，導致供水、通訊和醫療設施等重要設施無法使用。邊坡穩定性分析可預測自然邊坡的強度及可靠度的關鍵技術。本研究結合有限元素法與剪應強度降低技術，發展多物理場模型來分析地滑地之穩定，並模擬惠蓀林場的地滑事件，其中達西定律，被用來尋找流體在土壤之孔隙壓力及流率，並以莫爾庫侖定律分析地理彈性及塑性。此研究中，以有限元軟件COMSOL多重物理量模式，對降雨誘發的滑坡進行了耦合水力及大地之邊坡穩定分析，並以降雨、孔隙水壓力和地下水位擾動引起的土壤運動條件，比較崩塌前後高程與模擬成果，了解其準確性。結果表明，崩塌地穩定取決於地質、地形、邊坡幾何形狀、土壤類型和邊坡材料。水文和地文因子變化，會導致邊坡穩定度隨土壤強度參數的降低。本研究有助於預測臨界地下水位、壓力流線和位移，幫助大地工程師和災害專家發展早期預計系統，防止災難性滑坡的發生並減輕下坡造成的災害。[[abstract]] A landslide is a geological hazard that is perilous and a bringer of misfortunes. A landslide event will induce the loss of lives and infrastructure along with the non-availability of important facilities like water supplies, communication lines, and medical facilities. Stability analysis is a crucial technique, which can predict the strength and reliability of natural slopes. This study developed a Multiphysics model to analyze the stability of a deep-seated translational slide. The Finite Element Method combined with the shear strength reduction technique was used to simulate the landslide event for the Huisun forest area. Darcy's law was used to find the pore pressure and the flow rate of fluid in the soil. The geo-elastoplastic analysis was governed by the Mohr-Coulomb failure criterion. A coupled hydro-geotechnical slope stability analysis was carried out for a rainfall-induced deep-seated planar landslide slope by utilizing a finite element software COMSOL Multiphysics. The soil movement due to rainfall, pore water pressure, and groundwater level fluctuations was investigated. The landslide zone of pre/post landslide were compared with simulation outcome for accuracy estimation. Results indicated that the slope stability of the slide depended on the geology, topography, slope geometry, soil type, and slope materials. The slope stability reduces with the decrease of soil strength parameters due to hydrological and geotechnical factors. This study contributes to the prediction of critical groundwater level, pressure flow-lines, and displacements which can be used as key monitoring indices for the development of early warning systems by soil engineers and disaster experts to prevent catastrophic landslide occurrences and mitigate the disasters caused in the downslope