- 期刊
以物質點法探討光華崩塌地滑動面深度與地下水之影響
Investigation of Failure Surface Depth and Groundwater Effects in Guanghua Landslide through Material Point Analysis
摘要
現地調查與長期的監測資訊為邊坡整治工程規劃與設計的重要依據，然而許多時候因現場地形與環境因素使人力或機具無法進入調查，未能取得充分的地下資訊，導致難以完整的評析邊坡崩塌機制與量體，以至於無法規劃經濟有效的整治工法。為此，本研究以光華崩塌地案例分析為例，利用監測資訊配合物質點法數值分析結果，探討邊坡的滑動面深度，並預測其後續運動行為趨勢。數值分析結果顯示，光華邊坡破碎岩層中存在一滑動面，深度40～50 m，自下邊坡延伸至上邊坡，使上邊坡呈現下陷與下邊坡呈現隆起之情形，當滑動塊體崩移至趾部山溝，受束口效應提供抑制與阻擋效果，邊坡整體運動行為趨緩，符合光華崩塌地現況。然而，在高水位情境下，若岩屑層地下水位抬升至深度7 m以上，後續可能會發生岩屑崩滑。
並列摘要
Site investigation and long-term monitoring are crucial for planning and designing slope stabilization measures. However, specific in situ topographical and environmental constraints may prevent people and machines from accessing a site, which limits the slope data that can be collected. Therefore, in this case study, monitoring data and numerical analyses with the material point method were used to evaluate the failure surface depth involved in the Guanghua landslide and to predict its subsequent post-failure behavior. The numerical results indicated that the failure surface developed at a depth of 40-50 m in fractured rock and extended from the upper to the lower slope, causing the slope to settle at the upper section and rise at the lower section. When the sliding masses converged at a valley, the overall movement of the slope along the deep failure surface ceased because of topographical constraints. This numerical result corresponded to the field observations of the Guanghua landslide. The numerical analysis of a high-groundwater- level scenario also revealed that when the groundwater level inside the colluvium layer rises to 7 m below the slope surface, a subsequent landslide in the colluvium layer may occur.