碎形維度已逐漸被應用於節理面粗糙度之描述，目前對二維節理面碎形維度計算，多數係由一維碎形維度經加權平均方式間接求取其二維代表值，其中仍存有許多不便，進一步建立直接量測整體節理表面二維碎形維度之方法實屬必要。本文依據雙變數碎形布朗運動之自我相仿特性，建立一套可直接計算二維節理表面之 Hurst指數。並以隨機中點位移法及Blackmore碎形模式製造二維模擬節理表面，並同時利用三角柱頂表面積法與變異圖法計算結果與本文方法進行比較，以驗證本文方法之正確性。 The existing method for indirectly describing the two-dimensional joint surface roughness is usually weighted by the fractal property of numerous one-dimensional profiles in the surface. This paper develops a direct method to calculating the fractal dimension for a two-dimensional surface by employing the two-variable fractional Brownian motion theory. According to the self-affinity properties of a fractal surface, during scaling up and scaling down a surface, the intrinsic Hurst index that keeps the same roughness between these joint surfaces in different sizes is obtained. This method is evaluated by the fractal surfaces that generated according to the theory of the random mid-point-displacement method and Blackmore's anisotropic fractal model.
Relation:
岩盤工程研討會論文集=Proceedings of 2000 Taiwan Rock Engineering Symposium
