GEOTECHNICAL ASSET MANAGEMENT AND HURRICANE HELENE RESPONSE - NCDOT’S UNSTABLE SLOPE RATING SYSTEM IN PRACTICE

In 2016, the North Carolina Department of Transportation Geotechnical Engineering Unit (GEU) developed a Performance-Based Geotechnical Asset Management (GAM) Program. This program was designed as a GIS-based system where data would be collected in an ESRI^(R) app, Survey123 (™). In 2024, the NCDOT GEU received funding through a federal resiliency program to implement data collection on known problem slopes along Strategic Corridors. NCDOT awarded a contract to S&ME with Appalachian Landslide Consultants, PLLC as subcontractors that would carry out the field work.

On September 27, 2024, the remnants of Hurricane Helene dropped over 20 inches of rain on an already saturated landscape. This storm damaged, severed, or completely destroyed roads in Western North Carolina in thousands of places. To quickly capture the locations of failed cut and embankment slopes, as well as where debris flows crossed and closed roads, NCDOT enlisted the assistance of its consultants. Using the GAM database, the GEU + consultant team collected data at over 1,140 locations. Efforts were focused on sites that would require a greater design and construction effort than smaller sites that were quickly repaired with maintenance/general contractor efforts. The field work took place during the first four weeks after the storm and covered a variety of failure mechanisms, which elicited a variety of general mitigation recommendations. Having the GAM rating system and a trained team already in place shortened the reaction time and provided NCDOT with information about slopes that required immediate attention and engineering repairs.