LiDAR (Light Detection and Ranging) scanners are increasingly being used to measure discontinuity orientations on rock cuts to eliminate the bias and hazards of manual measurements which are also time consuming and somewhat subjective. Typically LiDAR data sets (point clouds) are analyzed by sophisticated algorithms that break down when conditions are not ideal, eg. when some of the discontinuities are obscured by vegetation, or when significant portions of the rock face are composed of blast fractures, weathering generated surfaces, or anything that should not be identified as a discontinuity for the purposes of slope stability analysis. This paper presents a simple LIDAR point cloud viewer that allows the user to view the point cloud, identify discontinuities, pick 3 points on the surface (plane) of each discontinuity, and generate discontinuities orientations using the three point method. A test of our 3-D LiDAR viewer for discontinuity orientations on three rock cuts in the Golden Gate Canyon Road area of Colorado is also presented.
Joint, fracture, fault, and discontinuity are the four common terms used to describe breaks in a rock mass. Discontinuity is probably the most general among the terms that suggests a break in the continuity of a rock mass, with no implied genetic origin . However, the term discontinuity makes no distinctions concerning the age, geometry or mode of origin of the feature . The term joint is commonly used to describe a discontinuity caused by a natural geological process. The term fracture is a more inclusive term that would include joints, faults, cracks, and breaks induced by blasting . A discontinuity is a significant mechanical break or fracture of negligible tensile strength in a rock, low shear strength and high fluid conductivity compared to the rock itself .