This thesis provides an assessment of the application of terrestrial LiDAR for rock mass characterisation and support design in drill and blast tunnels. The study includes establishing an appropriate work-flow for data acquisition in an operational tunnelling environment. This is determined through a full-scale pilot study, where the excavation of the Løren tunnel in Oslo, Norway, is followed over several months. An efficient work-flow for data processing and analysis for tunnel data is also established, using the software PolyWorks.
An analysis utilising LiDAR for mapping of geological structures and extracting their orientations is conducted. Because absolute georeferencing of the LiDAR data has not been obtained, this involves a reorientation of the dataset, where the tunnel axis is oriented to true north. The result of this analysis is compared to the geological field mapping conducted by the engineering geologist on site, and generally show a good agreement. Mapping of large-scale structural features is shown to be possible from the intensity returns of the LiDAR instrument. The discontinuity orientation analysis demonstrates suitability of employing LiDAR for extracting a high amount of orientation measurements to assist the engineering geologist in evaluating rock mass quality.
A study using LiDAR data for quantifying the roughness of the rock surface for establishing a new and improved method for calculating shotcrete volume is also included in this thesis. This study proposes two different parameters for calculating a roughness factor, appropriate for representing the true rock surface on which to apply shotcrete. The parameters include the mean profile length and the surface area of the blast round, as extracted from LiDAR data. The roughness factor calculated from surface area yields systematically higher values than the factor determined from profile lengths. A reduction of the area roughness factor is therefore proposed, by analysing how much the surface area decreases after a layer of shotcrete is applied. From the results presented in this study the chosen parameters appear to reflect the surface roughness of a blast round in a way that is useful for determining necessary shotcrete volume. However, further studies are necessary to confirm this.