Size effect of RQD and generalized representative volume elements: A case study on an underground excavation in Baihetan dam, Southwest China

Rock-quality designation (RQD) and representative volume element (RVE) are important parameters in analyzing the size effect and the continuum theory of rock masses. This paper used a case study on an underground excavation in the Baihetan Dam in Southwest China to obtain the RQD and the RVE size of the area. The size effect of the RQD was determined based on a three dimensional fracture network modeling. The concepts of generalized RVEs, which include the linear RVE (LRVE) and the cuboid RVE (CRVE), were proposed (with emphasis on LRVE). As opposed to RVE, LRVE considers the size effect of a given direction. The size effects in the directions were variable. A mathematical model for LRVE determination was also built. CRVE was determined based on the LRVE calculation.

► Generalized RVEs considering anisotropic feature in rock masses were proposed.
► Size effect of RQD in 3D fracture network model was determined.
► Mathematical solution method for LRVE considering 1D parameters was proposed.
► Two calculation methods for CRVE, which is cuboid shaped, were determined.