The Scope of Photogrammetry and TLS in the Context of Geomechanical Discontinuity Analysis

Discontinuity analyses along rock slopes become more and more important due to increasing safety requirements, especially for steep slopes like in quarries. The focus of this work is to determine quantitative discontinuity parameters such as orientation, persistence, and spacing, in relation to the slope orientation. In applied projects, the question for an optimized workflow in terms of discontinuity evaluation often arises. An integral approach of discontinuity set extraction can be provided by the combination of the following methods: 1. a quantitative manual recording of discontinuities (scanline sampling), 2. a semi-automatic technique (stereo-photogrammetry with the software ShapeMetrix3D), and 3. an evaluation applying an automatized algorithm to the point cloud data obtained by terrestrial laser scanning (TLS). These methods are applied at several quarries located in Variscan granitoids in the southwestern part of the Bavarian Forest (Germany). This contribution aims to discuss the possibilities and limitations of each method for discontinuity set evaluation in the context of applied failure analysis. Knowing geological structure will help us to determine the geomechanical behavior of the rock mass comprehensively, objectively, and reproducibly in further research, as well as to save resources and time.