JOINT SPACING - ANALOG AND NUMERICAL SIMULATIONS

Joint spacing distribution laws remain a controversial subject in the literature. In order to understand joint spacing, analogue and numerical modelling techniques were used. In the analogue model an evolution of the joint spacing distribution law during fracture development was observed as new fractures appear. Different processes for fracture initiation and propagation have been tested numerically including mid-point fracturing and partially or completely random processes. This study suggests that an initiation of fractures according to a random process could explain real joint spacing distributions. An evolution of joint spacing distribution laws from initially negative exponential to log-normal and normal is found with increasing joint development.