Geotechnical slope stability and rockfall debris related safety assessments of rock cuts adjacent to a rail track using aerial photogrammetry data analysis

Abstract

Transportation infrastructure facilitates the accessibility and mobility of goods, people, and services through its vast network spanning across the USA. The departments of transportation (DOT) agencies face many challenges in monitoring and maintaining these infrastructure assets for continuing their service and operations, especially those located adjacent to slopes in rural and remote areas. Mobilizing and conducting traditional infrastructure inspections in those conditions can be laborious and time-consuming. Also, the unstable or highly weathered rock slopes pose significant rockfall hazards due to the moisture content, intrusion, and temperature changes, transpired over a period of time, causing weathering and rockfalls, ultimately resulting in debris accumulation. Recently, unmanned aerial vehicles (UAVs) in conjunction with close-range photogrammetry techniques are being researched and used ubiquitously for infrastructure monitoring applications in and around mountainous regions. In this study, a rock-cut located in a remote terrain where a rail track was passing through was aerially inspected and imaged for performing a comprehensive safety assessment and analysis to evaluate the stability of rock-cut and ways to assess rockfall safety zones and boundaries. A unique approach was developed by leveraging the aerial mapping and data compilation along with an immersive three-dimensional visualization of slopes for conducting stability analysis followed by the evaluation of rockfall debris zones adjacent to rail tracks. Successful assessments conducted in this study indicate that the methodologies will benefit the transportation agencies in effectively monitoring and managing transportation infrastructure adjacent to hilly terrains and ensure the maintenance of safe clearance zones needed to safeguard the public and property.