Along the scenic Blue Ridge Parkway at milepost 400.8, a massive soil and rock slope plagued the National Park Service (NPS) for decades. Multiple landslides and rockfalls caused damage to the roadway that resulted in long-term closures. When the situation along the 120-ft-high and 500-ft-long slope worsened even after remedial actions, Schnabel was brought in to discover the cause and design a stabilization plan.

In 2002, NPS reduced part of the slide mass, removing debris, cutting benches, and establishing turf, but by 2006 additional cracks developed in the slope and the asphalt pavement at its toe continued to heave. The situation worsened, with cracks growing wider and longer, and new ones appearing in outlying areas. Excessive movement destroyed inclinometers installed in 2002.

At this point, Eastern Federal Lands Highway Division (EFLHD) and NPS asked us to determine the cause of the landslide. Our field reconnaissance to map the landslide and rock mass features revealed it was larger than originally thought. Based on our findings, we developed conceptual slope stabilization design alternatives with preliminary cost estimates, including anchored support and retaining walls. NPS and EFLHD selected and duly constructed the plan specifying high-capacity rock anchors at the toe, patterned rock anchors along the slope face, surface wire mesh, and filling the tension cracks with lightweight grout.