岩體因物理或化學作用導致節理面(Joint)發生，使岩體強度除了受到岩體本身影響外，也與節理面本身剪力強度有密切關係，岩體沿節理面發生剪力破壞而可能造成工程上財力與人力之損失。岩石節理面強度除了受節理面材料強度與岩石礦物間摩擦特性影響之外，節理面粗糙度(Roughness)也是重要之影響因素，通常用節理面之粗糙度係數(Joint Roughness Coefficient，簡稱JRC)來表示岩體節理面剖面之粗糙程程度，但此參數之決定並無客觀之定量方法，因此本研究利用統計學概念，來分析不同粗糙度係數下節理面剖面之空間變異性。研究方法包括：(1) 蒐集各種岩石節理面並將各剖面數值化，(2) 計算相對距離對應相關係數與半變異數，利用其關係擬合出自相關函數與半變異數函數以及(3) 分析在不同粗糙度係數下岩石節理面剖面之空間變異性。研究結果為(1) 每個等級之JRC剖面可以用半變異數函數來擬合，(2) 相關係數隨相對距離增加，變異性也會增加。;For rocks, it produces joints by physical or chemical effects. The strength is affected not only by shear strength of rock mass, but also of joints. Joints can cause strength to decrease and hence create damages to lives and properties. Joint roughness coefficient, rock material and friction between rock and mineral can influence rock joint strength. Joint roughness coefficient indicates roughness of rock profile. However, it makes deviation increase and effects the constructions without quantity. Therefore, in this research, we apply statistics to analyze spatial variability of profile with different joint roughness coefficient. Research approaches include: (1) we collect and quantify profiles. (2) We calculate lag distance, correlation coefficient and semivariance. Then, we simulate autocorrelation and semivariance function. (3) Finally, we analyze spatial variability of profile with different JRC. The result is that (1) we can apply a semivariance function to simulate profiles of different JRC. (2) When lag distance is large, variability of correlation coefficient is large.
