Determination of Representative Elementary Volume Size Using Synthetic Rock Mass Model

Rock masses commonly contain heterogeneous rock materials and a large number ofdiscontinuities. The engineering behaviors of a rock mass depend on ensemble properties ofconstituents, discontinuities and rock materials. This feature allows rock mass to possessscale-dependency, spatial dependency and directional dependency. Homogenization of aheterogeneous, fractured rock mass is often referred to as equivalent continuum approximation inthe fields of rock mechanics and hydrogeology. The concept of the representative elementaryvolume (REV) is the premise of the continuum method and essential and in the study andevaluation the properties of fractured rock masses in a multiscale manner. The goal of this study isto construct the methodology and procedure to quantify REVs of fracture intensity, hydraulicconductivity and mechanical properties of fractured rock masses. Both analytical and numericalapproaches will be adapted to determine the REV of fracture intensity. The variation of geometricalparameters with varied sampling size is quantified by using statistical analysis. The results derivedfrom analytical approach will be verified by discrete fractured network model and some casesstudies. The synthetic rock mass(SRM) will be employed to determine the hydraulic andmechanical REV and equivalent continuum properties for fractured rock masses, Discrete fracturenetwork (DFN) created by FracMan and PFC3D with bonded particle model and smooth-jointmodel are adapted to generate SRM model. A series of mechanical and hydraulic tests for syntheticrock masses with various sample sizes will be conducted. The coefficient of variation ofgeometrical, mechanical and hydraulic properties with different size of fractured rock mass arecharacterize statistically and then determine the REVs for geometrical, mechanical and hydraulicproperties based on the acceptable coefficient of variable.