Soil nailing is a construction technique that can be used as a remedial measure to treat unstable natural soil slopes or as a construction technique that allows the safe over-steepening of new or existing soil slopes. The technique involves the insertion of relatively slender, threaded reinforcing bars (rebar) or hollow-system steel reinforcing elements into the slope. Solid bars are usually installed into pre-drilled holes and then grouted into place using a separate tremie grout line, whereas hollow bars may be drilled and grouted simultaneously by the use of a sacrificial drill bit and by pumping grout down the hollow bar as drilling progresses. Bars are usually fully grouted and installed at a slight downward inclination with bars installed at regularly spaced points across the slope face. A rigid shotcrete facing or isolated soil nail head plates may be used at the surface. Alternatively a flexible reinforcing mesh may be held against the soil face beneath the head plates. Erosion control fabrics may be used in conjunction with flexible mesh facing for sloping faces or favorable, near vertical soil conditions.
Reference Materials
- FHWA-SA-96-069, "Manual for Design & Construction Monitoring of Soil Nail Walls"
- FHWA-SA-93-068, "Soil Nailing Field Inspectors Manual"
- FHWA-SA-93-026, "Recommendations Clouterre 1991 (English Translation)"