Effects of fracture size and normal stress on the shear behavior of a fracture as estimated by mortar replica

摘要

The effects of fracture size and normal stress on the shear behavior of a fracture were investigated in the direct shear tests by using mortar fracture replicas of different sizes, which were produced from a tensile fracture created in granite. Monotonic shear loading was applied at normal stresses of 0.3 and 1MPa for shear displacements of 2 and 20 mm. The change in the surface topography was measured by using a profile measurement system with a laser profilometer to determine the evolution of surface damage and aperture during shear. The results showed that the standard deviation (SD) of the initial aperture during shear increases not only with fracture size but also with normal stress since the matedness decreases due to the fact that asperities are more damaged with normal stress. Consequently, the non-linearity in the closure curve during shear increases with normal stress.