Fracture Surface Analysis of Kimachi Sandstone Deformed under True Triaxial Testing Condition

Abstract

In the field of fractographic study of rock mechanics, only the typical parameters such as line profile roughness, fractal dimension and root mean square roughness are used. However, these parameters are unable to represent the anisotropic surface structure. In this study, 3-dimensional point group data of fracture surface are analyzed by dividing them into short wavelength component of surface roughness and long wavelength component of waviness. Subsequently, we proposed a new method to identify the anisotropy of line profile roughness. The results of the proposed method show that: (i) waviness of fracture roughness decreases with increasing intermediate principal stress; and (ii) the anisotropy of line profile roughness was observed depending of the stress condition. These results show that the conventional evaluation parameters are not competent indicators in describing surface profiles uniquely, and hence 3-dimensional fracture surface parameters are needed to classify surface characteristics.