High Accuracy LiDAR in Underground Excavations for Geotechnical Mapping and Convergence Monitoring
LiDAR scanning can effectively measure change in shape as well as change in volume of underground excavations, and so it is ideally suited for ground movement and convergence monitoring. LiDAR is a ranged-based imaging technique that enables the rapid development of highly accurate 3-dimensional surface models. Either mobile or static LiDAR technologies are capable of generating 3D topographic models of a mine shaft or underground excavation with a spatial resolution less than 5 mm. Mobile LiDAR enables 3D data to be collected over spatially large regions efficiently and quickly.
The application of LiDAR for routine geotechnical mapping and ground monitoring provides full 3D coverage rather than the discrete data points provided by conventional field based mapping and ground movement instrumentation (i.e. borehole extensometers or convergence meters) respectively. This allows for detailed understanding of the geotechnical properties and potential early warning of ground movement prior to the onset of damage (for instance routine shaft inspections would detect minute convergence prior to liner deterioration).
This presentation will overview case studies where LiDAR has been deployed for detailed geotechnical mapping and ground movement/convergence monitoring in underground excavations ranging in size from 4 m to over 40 m in width. High accuracy data has been achieved so that millimeter scale deformations are observed.