Soil nailing is an effective technique for reinforcing in situ soils and creating gravity retaining walls for both permanent and temporary excavation support. This method is usually constructed from the top down and uses grouted, tension-resisting steel elements (nails).
First, the soil is gradually excavated, usually to a depth of three to six feet. After each stage of excavation, near-horizontal holes are drilled into the exposed face at intervals of three to six feet. Tension-resisting steel bars are then inserted into these holes and grouted in place. Once the nails are set, a drainage system is installed on the exposed face, followed by the application of a reinforced shotcrete wall facing. Precast face panels can also be used. Bearing plates are fixed to the heads of the soil nails, and this installation process is repeated until the desired wall depth is achieved. The result is a reinforced zone of ground that provides stability and support for the excavation.
Anchoring is commonly used for:
- Stabilize slopes and landslides
- Support excavations
- Repair existing retaining walls
Advantages of anchoring:
- Equipment is small enough to use in areas with restricted access
- Often a more cost effective and faster solution for excavation support
- Can be installed from crane-suspended working platforms for existing steep slopes, such as bluffs or existing retaining walls
- Allows excavation to start at the same time as the shoring system is being installed
