Numerical investigation of the effect of fracture intensity on deformability and REV of fractured rock masses

A rock mass consists of intact rock and various forms of discontinuities (e.g. joints/fractures, bedding planes and folds). Presence of joints, which are caused by internal stresses developed due to the change in stresses and temperature in rocks, would significantly affect the mechanical properties of rocks such as, deformation modulus and Poisson's ratio [1]. Mechanical parameters obtained from laboratory scale of rock samples are rarely representative of deformation modulus and Poisson's ratio of rock masses at field scale [2-6]. On the other hand, using field test methods for determination of these parameters of rock mass is difficult, time consuming and expensive, with largely unknown effects of the fractures nearby the test site [7]. Determination, up-scaling and calculating the equivalent continuum values of the mechanical parameters of rock mass in a large scale are essential for analyzing and designing of different engineering processes such as stability of underground spacing, rock slopes, holes and deep boring. Obtained results from the analysis are significantly affected by the values of mechanical parameters. Therefore, an accurate knowledge of the parameters plays a decisive role in different aspects of a rock engineering project.