CONTRAST OF ROCK FRACTURE SURFACE’S MORPHOLOGY CHARACTERIZATION BASED ON FRACTAL VARIATION

Abstract

In order to research roughness of rock fracture surfaces and interior damaged status of rock, some Brazil discs of white marble and sandstone are loaded to fracture by Brazil Test and the mathematical model of fractal variation is used to distinguish the morphology characterization of fracture surface of white marble from that of sandstone. Through computing the acquired scanned data of rock fracture surfaces, the following three results are obtained. First, the roughness of fracture surface increases with increase of loading angles, furthermore, the anisotropy of white marble fracture surface is more obvious than that of sandstone one. Second, under the same loading mode, by analyzing the mean fractal variation, the fracture surface of white marble is rougher than that of sandstone. Finally, rock disc specimens loaded to 1/2 or 3/4 of mechanics of mean fracture threshold still do not fracture at the first time loading, but their interiors have been badly damaged.