ABSTRACT
Joints are well known for their effects on the physical properties of a rock mass. Mechanical properties such as bulk elastic constants and shear strength are strongly affected by the presence of joints. This chapter focuses on the effect of surface roughness on the physical properties of fractures. Theoretical and numerical models of the contact of rough surfaces show that both the elastic normal and shear stiffnesses of a single fracture depend on the standard deviation of asperity heights. Fractures often dominate the fluid flow properties of a rock mass. Knowledge of the hydraulic conductivity of a single fracture is required for meaningful study of fluid flow through fracture systems. The parallel plate model can only be considered a qualitative description of flow through real fractures. The fractal model also allows realistic fracture surfaces to be generated by computer, allowing many physical properties to be studied by numerical simulation.
