Study on Representative Volume Elements Considering Inhomogeneity and Anisotropy of Rock Masses Characterised by Non-persistent Fractures

This study takes the rock masses in the dam foundation of a sluice gate of the Datengxia Hydropower Station in China as a case study to determine the geometrical and mechanical representative volume elements (RVEs) considering the special natures of rock masses (inhomogeneity and anisotropy). 3D fracture networks are generated on the basis of fracture data in the field and then used in this study for RVE determination. The representative parameters for RVE determination are selected and presented first. Through the comparison and analysis of the RVEs in different regions and directions, it is discovered that the inhomogeneity and anisotropy of the rock result in the spatial effect and directional effect in the RVE size, respectively. Therefore, the traditional method of RVE determination needs to be improved. Subsequently, on the basis of the sampling methods considering the special natures, the special natures of the geometrical and mechanical parameters are studied in detail and fully considered to improve the accuracy of the RVE results. Finally, the geometrical RVE size (10 m) and mechanical RVE size (18 m) are determined with the coefficient of variation. Moreover, the relationship between the geometrical and mechanical RVE sizes is also established.