APPLICATION OF 3D PHOTOGRAMMETRY TO ROCK SLOPE STABILITY ANALYSIS

As part of a semester undergraduate research project the authors compared the accuracy, availability and viability of 3D photogrammetry when applied to structural analysis. While it is imperative to include traditional methods of data collection and analysis in the study for rock slope stability controlled by geologic structure, emerging technologies are being utilized frequently today in all aspects of geological study. Advancements in smart phones, tablet computers, cameras, and software have made possible the collection and analysis of geological structure data faster, cheaper and safer than methods available a decade ago. Having already been taught the traditional methods, the authors explored various new methods on a small scale rock slope stability project. Specifically this research explored the accuracy and functionality of 3D photogrammetric methods with regards to geological data collection and slope stability analysis. The authors shot a series of digital photographs that were uploaded into photogrammetry software capable of automatically matching points to generate a single series of overlapping photographs suitable for processing into 3D point clouds. To establish a more comprehensive comparison, small sets of photos (2-5) were selected by the authors and matched using the software before structural analysis. The point clouds generated using this photogrammetric technique were then transferred to Split-FX software, capable of extracting strike, dip and dip directions of discontinuity surfaces that appear as planar patches within the point clouds. Results were then evaluated using RockPack III software to provide kinematic stereonet analysis of rock slope stability as controlled by the geologic structure.