IMPLEMENTATION OF UNMANNED AERIAL SYSTEMS (UAS) FOR THE DESIGN, RISK ANALYSIS, AND HAZARD MITIGATION OF ROCK SLOPES FOR THE VIRGINIA DEPARTMENT OF TRANSPORTATION

In October of 2018, researchers from the Radford University Geohazards and Unmanned Systems Research Center launched a study to determine whether the deployment of unmanned aerial systems with various sensors could provide data for the generation of 3D digital models suitable for rock slope design, risk analysis, and rock slope remediation. This was in response to a Research Needs Statement from the Virginia Transportation Research Council (VTRC) of the Virginia Department of Transportation (VDOT). VTRC is the funding agency. This is a progress report.

The objectives defined for this study are to: 1. Establish the methods, protocols, and workflow for safely using UAS for rock slope investigations along highways in accordance with federal, state, and local laws; 2. Test the accuracy of UAS mapping for specific rock slope applications using surveyed ground control points; 3. Provide aircraft and software recommendations and establish the workflow for extracting geologic structure data needed for stability analyses; 4. Establish the workflow for using UAS point clouds for rockfall modeling; and, 5. Test the use of change detection software for visualizing rock slope changes.

Multiple sites are included to test the suitability of UAS for rock slope analyses in a wide variety of settings and geologic conditions. To date, test sites include: I-77 at three locations along the Blue Ridge escarpment; Route 629 at Deerfield; Route 685 along River Road in Lynchburg; Route 340 near Harpers Ferry; I-64 on Afton Mountain; and, I-81 near Ironto.

Mission Types include: manual free flight; assisted intelligent flight; autonomous grid flights; autonomous double grid flights; and, oblique rock face mapping. Sensors include RGB photogrammetry, LiDAR, and thermal. The final report to VDOT covers such topics as: UAS operator training, including FAA remote pilot certification; mission planning; aircraft maintenance; flight operations; data processing; and, types of 3D rock mass visualization.