| 摘要: | 本研究針對陽明校區順向坡敏感區，考量不同位置之弱面及岩體裂隙對三維及二維邊坡穩定分析之影響，並探討本區順向坡滑動之機制與機率。首先，本研究根據現地岩心判釋資料，進行地層分層及裂隙密度及位態統計，結合LiDAR地表地形、層面方程及離散裂隙網絡（DFN）建構擬真三維地質模型，並由擬真三維地質模型建構考慮高角度節理的「裂隙簡化模型」，於極限平衡分析軟體Slide2/3觀察各情境下，關鍵剖面之潛在滑動及影響範圍。此外，針對下邊坡具保全對象及滑動影響範圍較大之剖面，利用點估計法及蒙地卡羅法進行可靠度分析。本研究分析之滑動面，主要位於崩積層(含回填土)下方砂岩層內不同位置以及砂頁岩互層內，並在未考慮地下水、校區建物(含邊坡穩定擋土設施)及地震力之假設下進行邊坡穩定分析。研究結果顯示，三維與二維極限平衡分析結果均顯示本邊坡屬穩定狀態，潛在滑動機制可能包含砂岩層內裂隙或砂頁層互層之弱面滑動。由可靠度分析結果可知，無論是利用點估計法或蒙地卡羅法評估裂隙傾角及岩體單壓強度對邊坡穩定之影響，各剖面於各情境下之滑動機率皆小於千萬分之一。本研究建立之三維及二維裂隙簡化模型，透過Slide3/2的等值異向性模式及弱面模型，可考量高密度平行層面裂隙或低密度高角度節理對邊坡穩定影響，分析出的滑動面會沿著裂隙及節理發展，形成非圓弧形滑動面。未來可透過此種建模方式，分析裂隙岩坡之滑動面。;In this study, we investigate the influence of weak planes and fissures in sedimentary rocks on the sliding mechanisms of a large-scale dip slope. First, the weak planes and fissures in the rock cores were identified as bedding planes, parallel-to-bedding fissures, and strike- and dip-joints. These weak planes were then analyzed statistically, considering their orientations and fracture intensities. Next, three-dimensional slope stability analyses were conducted, incorporating the identified weak planes into limit equilibrium models within the 3D geological models. Based on the results of these 3D slope stability analyses, eight 2D profiles were selected from the 3D model for further limit equilibrium and reliability analyses. This study focuses on sliding failure within the sandstone and interbedded sandstone-shale layers beneath the colluvium/backfills, without considering the effects of groundwater, campus structures (including the retaining structures), and seismic loading. The results of both the 3D and 2D slope stability analyses indicated that the dip slope, in its current state, is highly stable. The sliding mechanisms of this slope include sliding planes at both various locations in the sandstone or sandstone-shale interbedded layer, with some sliding planes forming stepped patterns. The reliability analysis results, which considered variables such as the uniaxial strength of the rock mass and the dip angle of parallel-to-bedding fissures, revealed that the sliding probability is less than 10⁻⁸. Additionally, the uniaxial strength of the rock mass has minimal influence on the sliding probability, while variations in the dip angle of parallel-to-bedding fissures may result in slightly different sliding planes, but with only a minor effect on the sliding probability. |
