Morphological Feature Description Method of Structural Surface in Borehole Image During In-Situ Instrumentation

It is of great significance to obtain the high precise structural surface properties of rock mass during the process of deep geotechnical engineering investigation by in-situ instrumentation, especially for preventing disasters and reducing damages. To obtain more detailed features of the structural surface in the image obtained by digital panoramic borehole imaging technique, this paper describes and analyzes the morphological feature of structural surface in the borehole image during in-situ instrumentation, and the feature is used to describe joint roughness coefficient (JRC) and analyzed the anti-sliding ability of borehole rock mass. We use a digital panoramic borehole imaging system to obtain the camera image and related data of borehole rock mass, extract the profile line of structural surface in the image, analyze the dip direction and dip angle, and transform the circular profile line of structural surface into three-dimensional feature. Finally, the statistical parameters of three-dimensional feature from the profile lines in each direction are calculated and used to form a roughness coefficient rose diagram according to related JRC theory. Results show that the rose diagram can well describe the actual three-dimensional morphology of the structural surface and its anisotropy of borehole rock mass structures. This paper provides a novel way to describe the morphological feature of structural surface in borehole image and can be applied to determine the dominant anti-slip direction of rock structure, which can solve the difficulty of obtaining the morphological features and mechanical properties of structural surface in deep rock mass.