本研究利用離散元素法之二維數值軟體PFC2D模擬岩盤承載之裂縫演化，首先探討顆粒微觀參數與整體材料巨觀參數間關連性之敏感度分析。再以三軸壓縮(含單軸壓縮)及巴西劈裂試驗之模擬，來檢核巨觀參數值，在可接受誤差範圍內即視對應之微觀參數為材料之參數，用以探討不同載重情況下之裂縫演化。
透過敏感度分析，發現顆粒元素數量大於4000顆時之巨觀材料參數值會趨於穩定。至於微觀參數與巨觀參數之關聯性，微觀參數之鍵結半徑放大係數對巨觀材料參數之影響最高，研究提出各微觀參數調整對各巨觀參數之高中低影響，作為微觀參數調整選擇之參考。
探討包含水平地表岩體承載(有、無鄰房)、傾斜地表岩盤承載等四種不同情況之基礎下方裂縫演化，及基礎下方周遭之最小主應力或圍壓狀況。當基礎有鄰近建築時，裂縫延伸較無鄰近建築少，且基礎下方之最小主應力隨著鄰房距離減小而增加。

The Numerical Software PFC2D is used to simulate crack evolution within the rock under various magnitude of foundation load in this study. The first part is to conduct the sensitivity analysis of eight microscopic parameters on six macroscopic material parameters. Triaxial compression test (including uniaxial compression) and the Brazilian test simulation were performed to verify the acceptable range of error of the macro parameter values.
Through sensitivity analysis, it is found that the macroscopic material parameter values will be stable if the number of particle elements is more than 4000. It also has been observed that the bonding radius magnification factor has the biggest influence on macroscopic material parameters. A sensitivity classification (high, medium, low) is made of eight microscopic parameters on six macroscopic parameter for the purpose of proceeding study.
The second part of this study includes the analysis and comparison of rock crack initiation and propagation beneath the foundation under various conditions, such as horizontal surface rock bearing (with/without addition of building structure) and the inclined rock surface. The minimum principal stress or confining pressure situation is also analyzed during the process. Some other findings from the study are, the influence of building structure in the model will make cracks to be less apparent than when there is no building structure nearby. Meanwhile, higher confining pressure will also be observed when the distance of the building structure is closer.

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