This evaluation was performed on shoot-in or “launched” soil nails based on information provided by the Federal Highway Administration (FHWA) and Soil Nail Launcher, Inc.
The soil nail launcher, typically mounted on an excavator, uses compressed air to launch 20-foot long, 1½-inch outside diameter steel or fiberglass tubes with closed steel tips into the ground in a single blast at speeds in excess of 200 miles per hour. The tubes can then be reinforced with a steel bar and grouted to achieve maximum strength. The tubes can also be perforated and pressure grouted to allow grout permeation into the soil, improving the adjacent soil properties and increasing the soil-nail bond.
A variation of karst sinkhole grouting is the grouting of mined coal seams and workings located below existing infrastructure that exhibit the potential to propagate to the surface and cause sinkholes and/or subsidence.