A Simple Method for Estimating the Joint Roughness Coefficient using Fractal Dimension

Joint roughness coefficient (JRC) is one of the most important properties of discontinuities to determine the amount of shear strength in Barton- Bandis (1982) failure criterion. One of the weaknesses of this parameter is its high dependence on personal judgment in adapting the joint profile to the standard sections of Barton and Choubey (1977). Various methods have been devised to solve this problem, the aim of the paper is a simple formula based on fractal dimension. In this study, two relationships based on fractal dimension by box counting and correlation dimension methods are presented for estimating the joint roughness coefficient. Also, the value of JRC using them is estimated for 192 rock joint profiles and compared with other JRC determination relationships. Accordingly, in these equations, sharing of the asperity amplitude to profile length ratio, in addition to the fractal dimension parameter, increases the accuracy and wider range for calculating the Joint roughness coefficient than single-parameter relations.