Discontinuities in rock masses have an important influence on the deformational behavior and stability of deep underground spaces, and the surface roughness of discontinuities in rock masses is an important factor to analyze the mechanical and hydraulic characteristics of rock joints. In this study, we carried out direct shear tests on rock joints under both constant normal load (CNL) and constant normal stiffness (CNS) conditions, and measured the surfaces of rock joints before and after shear by using a 3-D laser scanning profilometer system. By using the projective covering method (PCM) and the measured data, we evaluated the relation of surface characteristics of rock joints to their shear behaviors. Moreover, a new hydro-mechanical test apparatus for rock joint was developed, based which a number of coupled shear-flow tests were conducted to estimate the hydraulic behavior of rock joints during a shear process.
