Inter-relationship between joint dilatancy and frictional resistance: impact on fracture behaviour

Rock joints possess features that alter both the characteristics of rock formations and the fracturing process. Two important properties that govern the shear behaviour and dilatancy behaviour of discontinuities have been analysed in this paper by the discrete element method (DEM). The ability of a frictional joint to suppress fracture growth decreases as the frictional resistance increases; however, the rate and extent of fracturing increases with joint dilatancy. The influence of joint frictional resistance is more dominant at high values and in this range effects of small magnitudes of dilatancy are correspondingly insignificant. At low joint friction the occurrence of even a small amount of dilation increases the severity of the fracturing process. This study highlights the interactions between two main joint properties with the anticipation that the concepts derived here will be useful for predicting fracture behaviour at the subsurface.