為了探討萬山D048大規模崩塌區在不同降雨強度下的三維邊坡穩定性分析，本研究使用GMS (Groundwater Modeling System)建立研究區域的三維地質模型及夏季常時地下水位面，並透過地電阻探測資料對數值模型進行簡單的校正，使模型更貼近現實情況。此外，本研究使用FLAC3D (Fast Lagrangian Analysis of Continua in 3 Dimensions)中內建的FISH語言編寫飽和-非飽和滲流場模型，透過基質吸力的變化去修正非飽和土壤的滲透系數與有效應力場，並透過一維砂柱入滲試驗資料驗證模型的適用性，實現非飽和降雨入滲行為。
本研究以SCS曲線號碼法(Soil Conservation Service Curve Number)設計邊坡的有效降雨量，以五種不同降雨強度進行三維邊坡穩定性分析。並將研究區域內的傾斜儀監測值與模擬結果進行比對，檢視兩者間的吻合度，以此驗證模型的可靠性。隨後，根據安全係數將潛勢區內的邊坡進行可能發生崩塌的危險程度分級，並透過剪應變增量推估不同降雨強度下的潛在崩塌深度與體積量。
分析結果顯示，降雨強度200 (mm/day) 便會達到大規模崩塌標準，邊坡的破壞模式以淺層崩塌和土石流為主，並且在潛勢區內的西側野溪與高132線交會處具有大範圍邊坡破壞發生可能性。

To investigate the three-dimensional slope stability analysis in the Wanshan D048 large-scale landslide potential area under different rainfall intensities, this study uses GMS to build a three-dimensional geological model of the study area and the summertime ambient groundwater table and makes corrections to the numerical model through earth-resistivity method data to make the model closer to the real situation. In addition, the saturated-unsaturated infiltration field model was developed using the FISH programming language built into FLAC3D. The infiltration coefficient and effective stress field of unsaturated soil were modified by the variation of matrix suction, and the applicability of the model was verified by the one-dimensional sand column infiltration test data to realize the infiltration behavior of unsaturated rainfall.
In this study, the effective rainfall on the slope was designed by the SCS curve number method, and the three-dimensional slope stability analysis was conducted with five different rainfall intensities.
The conclusions of the results of this study show that when rainfall intensity of 200 mm per day would reach the standard of large-scale landslide. The slope damage pattern is mainly shallow landslide and debris flow.

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