Case History: Failure of the Reinforced Soil Slope at Yeager Airport, Charleston, West Virginia

Abstract

The 73-m-tall (240-ft) reinforced soil slope (RSS) that supported Runway 5 at Yeager Airport in Charleston, West Virginia failed catastrophically on March 12, 2015 after a service period of about 8 years. In the context of the slope’s stability, this case history describes the RSS design, construction, and performance up to the failure, as well as the postfailure investigation. The postfailure investigation revealed a fill–rock interface region composed of degraded sedimentary rock below the RSS. Shear strength characterization included 150-mm-diameter (6-in.) consolidated drained triaxial tests on the coarse-grained fill (more than 50% gravel and cobble sized) and fully softened and residual shear strength tests on fine-grained soil from the fill–rock interface region. Limit equilibrium analysis reasonably explained failure by considering changes in shear strength in the sedimentary rock. Although the lowest calculated factor safety was behind the RSS, a local minimum of the calculated factor of safety corresponded closely with the observed failure surface.