Launched soil nails are a unique remedial technology in the geotechnical construction toolbox. These 20-ft-long, 1.5-in.-diameter nails are installed in a single shot using a compressed air “cannon” at velocities of up to 250 miles/hour, and at rates approaching 250 nails/day. The nails reinforce an unstable or potentially unstable soil mass by transferring the nail’s tensile and shear capacity into the sliding soil. However, at least as interesting as the tool itself, is the story behind the development of launched soil nail technology over the past 30 years.
A Mid-Atlantic state’s Department of Transportation (DOT) and its historical preservation group wanted to repair and rehabilitate a failing rock wall within a town in Appalachia.