: This paper presents a numerical method for deriving the equivalent mechanical and hydraulic properties of fractured rock masses using the Distinct Element Method (DEM). Based on 2D fracture system realizations, numerical experiments were performed on a series of square DEM models of increasing side lengths with constant velocity or constant hydraulic pressure gradient boundary conditions. Representative Elementary Volumes (REVs) were established as the minimum model area after which the average mechanical and hydraulic properties maintain constant values. The results of numerical simulations show that DEM can be an effective numerical tool for the homogenization of the hydro-mechanical properties of fractured rock masses.
The fact that the properties of rock samples measured in the laboratory-scale cannot represent the field-scale properties of rock masses has always been the weak point for the solutions of many rock engineering problems, especially for the numerical method applications (Pariseau 1999). Because the confidence of the numerical simulation is highly dependent on the properties of rock masses, the development of the proper method to determine the hydro-mechanical properties of rock masses is very important. The attempts to determine the “equivalent ” properties of rock masses using numerical methods from the given characteristics of intact rock and fractures can be justified because it is very difficult to measure the field-scale properties of rock masses directly.