Triangulation-based 3D laser imaging for underground rock mass characterization: Impact of operational parameters

This paper examines the application of triangulation-based laser imaging for rock mass classification. Most case studies in this area have focused on the application of LIDAR and photogrammetry surveys. Triangulation-based 3D laser cameras are a worthy alternative although little research has been conducted. These cameras are designed for short-distances, usually less than 10 m, and are typically immune to the ambient lighting conditions. Three spatial coordinates (X, Y, Z) and the reflection intensity (I) are acquired by triangulating the projected and reflected laser beam paths. A typical image can take between 1-10 minutes to acquire and contain up to 1 million image elements at sub-millimeter accuracies. The short range, immunity to lighting conditions, and high accuracy of these cameras are ideal for an underground environment where there is limited space and lighting, and where the rock face features can be very subtle. A case study was conducted in an underground mine where good correlation was found between joint set orientation measurements acquired manually and with a triangulationbased laser camera. This correlation validates the triangulation-based laser imaging technology and the methodology used for image processing and analysis. Overall, there is good potential in the application of triangulation-based laser imaging to aid in rock mass classification. Copyright 2008, ARMA, American Rock Mechanics Association