Computer Estimation of JRC Index Using Function Moments

Abstract

The paper deals with a shape of geological discontinuities. This shape significantly affects the stability of rock massifs. The joint roughness coefficient (JRC) is one of the main shape indicators but the methods of its estimation are based on the empirical analysis of fracture curves in present. We propose a new mathematically correct theory of automatic estimation of the JRC. It shows that determination of the JRC should be based not only on subjective experience, but objective shape characteristics should be used as well. The moment method is one of the possibilities. The principal moments of a fracture surface and the elongation of so called equimomental ellipse can be determined as the possible characteristics of the shape of a fracture surface. The paper introduces a software which is able to reconstruct a 3D profile of a scanned surface and to assign its JRC index automatically.