| 摘要: | 本文將邊坡模型架構歸納為數值地形模型、地工模型、離散裂隙網絡及數值分析方法四項要素所構成，並透過這四項要素建構一個可應用於現地邊坡穩定分析的數值模型。此外，本文以陽明交通大學陽明校區及其周邊邊坡(簡稱陽明邊坡)為例進行穩定分析，希望藉數值邊坡模型辦別穩定性欠佳之位置。
本文導入減面(Decimation)技術，透過對DEM資料進行處理，建構出一降低記憶體浪費且能提升運算效能的網格面地形圖。而後再使用離散元素分析軟體PFC3D建構一個近似於現況的陽明邊坡數值模型，並以此進行穩定性分析。而後再透過同時弱化岩石材料及不連續面，探討不同強度折減因子（SRF = 2、5、8）下陽明邊坡的穩定性、滑動影響範圍。此外，本文亦以不同地質條件(岩石材料、不連續面)個別作為弱化對象，以崩塌能量判別各項地質條件對於邊坡穩定性的影響程度。
結果顯示：在SRF=1、2時，位移量、高程及崩塌能量皆呈現較低的變化。然而，在SRF=5與SRF=8時，陽明邊坡整體出現大範圍滑動與高能量釋放，故推估陽明邊整體安全係數可能介於2至5之間。此外，對不同弱化對象（岩石材料、不連續面、兩者同時）分析後得到地質條件對邊坡穩定性的影響程度為：岩體+不連續面>>不連續面>岩體，而在三組不連續面( ILB、SC、L4)中，平行層面裂隙(SC)影響最為顯著。
;This study conceptualizes the slope modeling framework as comprising four essential components: Digital Terrain Model (DTM), Geotechnical Model (GM), Discrete Fracture Network (DFN) and Numerical Analysis Method (NAM). These four components are integrated to construct a numerical model applicable to in-situ slope stability analysis. This study uses the slopes within and surrounding the Yang-Ming Campus of National Yang Ming Chiao Tung University (abbreviated as the Yang-Ming Slope) as a case study to evaluate in-situ stability and delineate potentially unstable regions.
To enhance simulation efficiency and reduce memory consumption, decimation technique is applied to the DEM to generate an optimized terrain geometry. Then, a numerical slope model nearly representative of the in-situ conditions was established by the discrete element method software PFC3D, and used to conduct a stability analysis. Subsequently, both rock materials and discontinuities were simultaneously weakened to investigate the stability and sliding impact range of the Yang-Ming slope under different strength reduction factors (SRF = 1, 2, 5, 8). In addition, this study also examines different geological features (rock materials, discontinuities) individually as weakening objects, using collapse energy to assess the impact of each geological features on slope stability.
The simulation results reveal that under SRF = 1 and 2, the Yang-Ming Slope exhibits minimal displacement, elevation change, and collapse energy, indicating a stable condition. However, significant slope movement and collapse energy release were observed at SRF = 5 and 8, suggesting that the factor of safety (FS) for the slope lies between 2 and 5. Comparative analysis of different weakening scenarios indicates that the degree of influence of various geological conditions on slope stability follows the order: rock mass + discontinuities >> discontinuities > rock mass. Furthermore, among the three analyzed discontinuity sets( ILB、SC、L4), the bedding-parallel fractures (SC) had the most pronounced impact on slope instability. |
