Measurement of rock joint roughness by 3D scanner

Abstract

Many methods have been used to measure rock joint surface roughness more accurately. However, true roughness has been distorted and underestimated by differences in the sampling interval of the measurement methods. Thus, current measurement methods produce a dead zone and distorted roughness profiles. This study proposes a new rock joint surface roughness measurement method by use of a camera-type three-dimensional (3D) scanner as an alternative to current methods. For this study, the underestimation of artificial roughness is analyzed by using the current measurement method of laser profilometry. We then replicate eight specimens from two rock joint surfaces, and digitize them by 3D scanners. Finally, the roughness coefficient values obtained from eight numbers of the 3D surface data sets and from 320 numbers of two-dimensional profiles data sets are analyzed by using the current measurement methods and our proposed measurement method. The artificial simulation confirms that the sampling interval is one of main factors for the distortion of roughness and shows that current methods may not consider the inclination of waviness. The experimental results showed that the camera-type 3D scanner produced 10% larger roughness values than those of the current methods. The proposed new method is a faster, more precise and more accurate method than the current methods for the measurement of rock joint roughness, so that it can be promising technique in this area of study.