An investigation on the correlation between the joint roughness coefficient (JRC) and joint roughness parameters

Abstract

Correlation of the joint roughness coefficient (JRC) and various parameters for joint roughness evaluation was investigated in this study. A high-resolution 3D laser scanner was employed to precisely record roughness characteristics of 16 tensile fractured rock joints with different sizes. Direct shear tests were then conducted on rock joints and employing Barton’s equation, JRC for each joint is back-calculated. Joint profiles were retrieved from the captured 3D joint planes and roughness statistical parameters including Z2, SDi,Rp, and SF were calculated for each profile at 3 different sampling intervals (0.02 mm, 0.05 mm, and 0.1 mm). It was understood that Z2 and SF had the strongest correlation with JRC. Several equations were proposed for estimation of JRC using statistical parameters most of which yielded similar results to previous related research. Based on the findings of this study, all statistical parameters except SF experience a devaluation when sampling interval increases while SF value increases somewhat drastically with a raise in sampling interval. It was concluded that the sampling interval has a significant impact on all studied parameters and must be carefully chosen so further errors can be avoided.