Abstract:
Wyoming Highway 22 is a heavily traveled commuter road between Jackson, WY and Victor Idaho. Many workers use this route, through the Teton Pass, to commute to their jobs in Jackson Hole. On June 7, 2024, following a heavy rainstorm and significant snow melt, a large landslide occurred that led the Wyoming Department of Transportation to close the road.Â
A temporary run-around road was constructed in three weeks, but the geometry for a permanent fix required significant excavation of the slide debris, foundation preparation, drainage upgrades and the use of lightweight fill to repair the roadway. A 1.5(H):1.0(V) Reinforced Soil Slope (RSS), specifying lightweight foamed glass fill and multiple layers of Geogrid was designed. For safe construction and stability, soil nailing was used as temporary shoring for the RSS construction.Â
Subsurface conditions for the soil nail design were not well-defined. WYDOT mobilized to drill several borings, but available locations were limited by access due to the huge debris field and access road limitations.
Soil shear strength values for the design of the soil nailing were back-calculated from the known geometry of the site pre-failure, while varying the ground water level. 60,000 square feet of shoring was required. Hollow bar soil nails were installed, utilizing a geotextile and wire mesh facing in addition to horizontal drains and a significant micropile scope used as pins to stabilize the base of the new fill.