A DFN–DEM Approach to Study the Influence of Confinement on the REV Size of Fractured Rock Masses

Abstract

In several situations, it is required to conduct numerical tests on jointed rock samples to assess their behavior under different stress paths. To this aim, determination of representative elementary volume (REV) of jointed rock mass is a prerequisite task. However, REV of jointed rock masses is traditionally determined by conducting uniaxial tests which ignores the effect of confinement. To study the effect of confinement on REV size, a numerical study based on discrete fractured network–discrete element method (DFN–DEM) is performed on synthetic fractured rock masses. In this regard, different parent DFN realizations have been generated and smaller samples have been extracted. Thereafter, several DEM simulations including uniaxial, biaxial, conventional triaxial and true triaxial stress conditions have been conducted on the samples and REV sizes have been assessed based on peak strength. To investigate the effect of confinement on REV size, different confining pressures have been imposed on rock blocks via conventional triaxial stress condition. It has been observed that the increase in confining pressure intensity up to a certain limit results in a considerable effect on REV size. However, beyond a limit, the increase in confining pressure will not have considerable effect on REV size. The results of simulations also revealed that providing more confinement faces leads to smaller REV size.