Photoelastic study of the contact mechanics of fractal joints

Abstract

The Earth's crust exhibits numerous fractures and weaknesses which significantly affect the mechanical behaviour of rock masses, such as the deformation, strength and conductivity, in which the surface roughness of rock fractures plays a dominant role. To take the influence of roughness into account, efforts have been made to characterize the surface roughness of rock joints. The brittle elastic properties of rock joints can be approximately simulated by using photoelastic material and an investigation has been performed on epoxy specimens cast against natural rock joints. In order to cntrol the roughness and to display directly the fractal effects on the mechanical behavior, a series of synthetic fractal joints with different fractal dimensions is tested in the present study by using the photoelastic method under uniaxial compression and direct shear.