A Survey of 3D Laser Scanning Techniques for Application to Rock Mechanics and Rock Engineering

Abstract

3D laser scanning techniques have been developed since the end of 1990s for 3D digital measurement, documentation and visualisation in several fields including 3D design in the processing industry, documentation and surveying in architecture and infrastructure. By using a 3D laser scanner, a tunnel or underground construction can be digitised in 3D with a fast scanning speed and high resolution up to millimetre level. The scanning data consists of, not only X-Y-Z co-ordinates, but also high resolution images, either gray-scale (with reflex intensity data) or colour (with RGB data), and then can be transformed into a global co-ordinate system by control survey. Therefore, any rock engineering object with its as-built situation can be quickly recorded as the 3D digital and visual format in a real co-ordinate system. In this case, it provides a potential application for 3D measurement, documentation and visualisation with high resolution and accuracy. In order to investigate the current development of the state-of-the-art of laser scanning techniques and its potential application to rock mechanics, ISRM therefore set up the ISRM-Swedish National task in 2007 during the ISRM Congress in Lisbon through the Swedish Rock Mechanics Group (BeFo). The task focused on three parts: (1) Investigate the state-of-the-art in the current development of laser scanning techniques; (2) Summarise the application examples by using laser scanning techniques to rock mechanics projects; (3) Evaluate the limits and needs for further development. In this report, the purpose of this study is described first, and then the current development of laser scanning techniques (both hardware and software) is summarised. Based on the literature review and some case studies, the current status of the application of laser scanning techniques to rock mechanics is presented. Finally, the limits of current development and the needs for further development are discussed.