Investigating the Scale Effect of Rock Mass in the Yangfanggou Hydropower Plant with the Discrete Fracture Network Engineering Approach

It is well known that there is a significant difference between the strength of an intact rock sample and that of an in situ rock mass. Studying the scale effect of a rock mass is important for the estimation of the rock mass strength. Discrete fracture network engineering (DFNE) has become a widely used technique in rock mechanics. However, its applications in scale-effect studies remain limited. One of the reasons might include the required cumbersome structural data mapping work. The major advantage of the DFNE application in a scale-effect study would be the capacity to investigate the scale effects of various parameters simultaneously. This paper provided a case study of an investigation of the scale-effect for a fractured rock mass with the DFNE approach. The rock mass of the right-bank slope of the Yangfanggou hydropower plant, China, was taken as the study case. A digital photogrammetry technique was adopted to perform the rock mass structural data mapping. With the collected data, DFNE models were constructed, in which the fractures are considered as circular discs with finite size. The DFNE models were used in the scale-effect study for both the rock mass structural parameters and equivalent mechanical parameters via a discrete-element method (DEM)-based synthetic rock mass (SRM) technique. The comprehensive representative elementary volume (REV) scale and the macromechanical parameters for the rock mass were proposed.