Fractal evolution of surface roughness of rock joints in shear

By means of modified shear tests, the fractal evolution of surface damage of rock joints in loading history has been investigated regarding to the changes hi roughness characterized by the fractal dimension D and the intercept A. The study shows that the surface damage displays anistropy. The degradation of surface roughness depends on the initial values of D and,A, the normal force applied, the tensile strength of rock materials and the shear distance. Taking into account the factors mentioned above, an empirical evolution law of surface damage of rock joints is developed.