Tennessee Dept. of Transportation, SR 70 - Emergency Letting
Hawkins County, Tenn.
Owner: Tennessee Dept. of Transportation
Contractor: Blalock Construction
Lead Design Firm: GeoStabilization International
In the early morning hours of Feb. 21, 2019, a massive landslide occurred on Tennessee’s State Route 70 in Hawkins County, sweeping away both travel lanes. Earthen material from the landslide flowed downhill onto the lower portion of the highway, making the route impassable. Tragically, before officials could close the road, two vehicles drove off the missing section of highway and crashed below, killing one driver and injuring the other. GeoStabilization International’s original stabilization repair comprised soil nails and a high-tension mesh facing. Once the slope was secured, Blalock Construction built a massive rock buttress to secure the roadbed. During construction, due to the saturated soil, continued rain and slippery slope conditions, crew members worked under rope-access conditions and had to be tied off for safety. Even when tied off, conditions limited radial movement of crew and equipment along the slope. Once crews started drilling the third row of soil nails, the slope gradually became flatter and equipment more stable. Throughout the project, subsurface information from the soil-nail drilling allowed GeoStabilization to refine the design and ultimately arrest the landslide movement with fewer materials than originally planned, reducing overall project costs.