Abstract:
Unmanned aerial vehicles (UAV) have the potential to become powerful site reconnaissance and data collection tools for in geoengineering. UAVs are expected to become particularly useful in geomechanics applications such as rock mass characterization, landslide imaging, and failure analysis, as part of post-disaster reconnaissance, or conventional engineering practice. A low-cost quadrotor UAV has been used as a data acquisition platform for optical imagery at a number of sites affected by the 2015 Gorkha earthquake in Nepal. The UAV collected images of landslides that would normally be very difficult, or expensive to access. Two example landslides are presented in this contribution. Structure-from-motion photogrammetry was used to generate 3-D point clouds and meshes for each site. These models were geometrically scaled using field survey measurements and used as the primary component of a landslide rock characterization scheme. 3-D models were also used to define landslide post-failure geometry. Models were used to delineate the orientation of 3-D features in the rock structure such as fractures, bedding, foliation, and stratigraphy. Multiple failure modes, including wedge failures, were also identified from 3-D models. The results of this study demonstrate the capabilities of UAVs as a tool for characterization and data collection at rock sites.
Introduction
The popularity of unmanned aerial vehicles (UAV), or drones, has increased in recent years. UAVs have been used to collect optical imagery related to many engineering applications (Lin et al., 2015; Gillins et al., 2016; among others). Most commonly, the collected imagery is only used for qualitative assessments. Recent efforts have been made to introduce more quantitative assessments (Ellenberg et al., 2014; Hugenholtz et al., 2015), however, more advancements are needed to fully exploit the collected data. The increasing prevalence of UAVs along with rapidly advancing technology, presents a tremendous opportunity for UAV platforms to become powerful data collection tools in geoengineering. New technologies coupled with established imaging methods allow for low-cost UAV platforms to be useful for many geomechanics applications.
