Remote analysis of rock slopes with terrestrial laser scanning for engineering geological tasks in reservoir planning

Abstract

Building the lower basin of a pumped-storage hydropower plant in an active limestone quarry without any sealing is a challenging project. A proper site investigation is crucial to increase the overall efficiency of planning as well as realisation by anticipating potential problems and sticking points. The local geology comprises a complex system of reef structures and bedded sequences that is intersected by faults. Sets of faults can be identified on different scales and the fracturing patterns vary vertically and horizontally. Both the ongoing quarrying as well the sheer size and steepness of the outcrop prevent any extensive data acquisition using traditional methods. Therefore, terrestrial laser scanning (TLS) was used to map the quarry and to create a high resolution digital elevation model (HRDEM). The HRDEM allows to perform spatial analysis with respect to the distribution of geohydraulic and geotechnical properties of the rock mass in the quarry. The major advantages of this approach are the increased level of detail, a substantial improvement of documentation and synergetic effects that arise from the multiple different applications of scan data e.g. for analysis, interpretation, planning and solving geohydraulic and geotechnical issues. It has shown in practice that this multi-facetted usage of the collected data outweighs the initial efforts of data collection and processing by far.