Estimation of REV for Danba schist based on 3D synthetic rock mass technique

Abstract

This paper aims to provide a case study of determining the structure and mechanical Representative Elementary Volume (REV) simultaneously for a specific jointed rock mass. The schist of Danba HPP project is taken as the study case here. A Synthetic Rock Mass model (SRM) is firstly constructed based on sophisticated geological loggings. With which the number of joint centers per unit volume (P30), the area of joint per unit volume (P32), and the Young’s modulus (E) are examined for various sample sizes. It is found that the SRM is a powerful tool to address those problems. The P30 reduces gradually with the increase of rock mass scale. As for P32 and E, maximum and minimum value and the variance decrease rapidly with the increase of rock mass size. A comprehensive REV size of 50~60m is then estimated based on the above 3 indexes. According to the SRM simulation, young’s modulus of the REV scale is around 6.8GPa, which is a little bit higher than the recommended value by geologists. This difference is believed to be reasonable as the recommended value usually been significantly undervalued. The procedures and findings of this paper may provide a certain reference for further studies on rock mass scale effects.