The special specification was created and originally issued by EI 05-026 to provide designers with another option for stabilizing earth slopes that show evidence of localized surface failures. The installation of launched soil nails will improve or reinstate the strength and stability of the soil structure. This treatment is intended for shallow slope sloughs where the slip plane is within the minimum three meter soil nail embedment depth. Soil nails are long steel or fiberglass rods installed to reinforce or strengthen the existing ground. Recently, there has been a development in the installation process which incorporates a tool utilizing compressed air to launch a soil nail into place. Applications of the installation method include the ability to work beneath most overhead utilities, relatively rapid installation process (approximately 25 linear meters of road per day for a two-row installation), minimum ground disturbance, single lane closure for mobilization, and installation from the top of the affected slope. The installation method is not appropriate for use in very compact soils or soils containing a significant quantity of boulders and/or cobbles. Underground utility mark-out is required to avoid damage by the installation process. Design methodology may be found in the FHWA publication listed in the references.
