Surface expressions of discontinuities, and the estimation of their 3-D orientations using combined LiDAR and optical imaging

The importance of the collection and analysis of data on discontinuities cannot be overemphasized. Problems which include sampling difficulties, risks, limited access to rock faces and exposures, and the delay in data collection has led to a high need for data collection tools and analysis techniques that can overcome these problems.;Discontinuities manifest themselves as either traces or as facets. Traces are linear features that intersect with both the discontinuity and the rock cut. Facets are the actual discontinuity surfaces that are exposed in the rock cut. Facets can be natural or induced. Identifying a facet as either natural or induced can sometimes be very difficult and can affect analytical results. The orientation of facets can be estimated from LiDAR point cloud. The orientation of traces can be estimated from optical imaging methods. LiDAR scanning alone cannot measure traces, neither can optical imaging methods measure facets. This is complicated by the fact that both facets and ‘traces’ are often present in the same rock cut, making the selection of an appropriate methodology or tool very difficult if not impossible. The set of traces in a rock mass usually belong to a set of facets of the same rock mass. These set of traces and facets can be combined either by the use of stereonets or by the equation of the angle between two lines.;This research has provided a simple method by which the orientation of facets can be estimated from LiDAR point cloud. It has also provided a simple method by which the orientation of traces could be estimated from 2-D images. Additionally, this research has provided a reasonable way by which professionals could differentiate between traces, natural, and induced facets. Finally, this research has provided a methodology by which traces from optical images can be combined to facets from point cloud data.