AN INTEGRATED APPROACH TO ASSESSING POTENTIAL ROAD-FILL FAILURES AND DOWNSLOPE HAZARDS

The combined anthropogenic and natural influences on slope stability of constructed road-fills in mountainous topography warrants that this phenomenon is studied from multiple perspectives within the civil engineering, geologic, and environmental science disciplines. However, a comprehensive, interdisciplinary approach to understanding and forecasting road-fill failures is not apparent in the scientific literature. Ongoing work along the Blue Ridge Parkway, North Carolina demonstrates the effectiveness of such an approach. Field work conducted by the Federal Highway Administration, the US Forest Service, the US Geological Survey, National Park Service, and academicians serves as the dataset for GIS-based and numerical modeling that will culminate with the generation of a road-fill failure and associated debris-flow hazard forecasting system for use by federal land managers. GIS applications include the use of VisiData, spatially referenced digital imagery that includes a 160° forward view of the roadway as well as quantitative analyses of surface pavement conditions. Other GIS tools utilize existing slope-stability models and numerical modeling to forecast and map portions of the road network susceptible to slope failure. A mechanically based numerical model, programmed in Python, was designed to provide insight into what amounts and locations of hydrologic recharge are necessary in order to increase landslide risk. Potential sources of fill-material recharge include pavement cracks, breached culverts, groundwater seepage and road runoff. Additionally, environmental hazards, such as sediment flux into streams, loss of historic/cultural resources, and impacts to natural and modified habitats, can be assessed in a GIS framework by combining field and remote sensing data.