Soil nailing uses grouted, tension-resisting steel or glass fibre composite elements (nails) to reinforce in situ soils to create a gravity retaining wall for permanent or temporary excavation support.

Keller rig installing soil nails

Common uses

Stabilise slopes and landslides
Support excavations
Repair existing retaining walls

Process

Soil nail walls are generally constructed from the top down. Typically, soil is excavated in 1m to 2m deep stages. After each excavation stage, near-horizontal holes are drilled into the exposed face at typically 1m to 2m centres. Tension-resisting steel bars are inserted into the holes and grouted in place. A drainage system is installed on the exposed face, followed by the application of reinforced shotcrete wall facing. Precast face panels can also be used. Bearing plates are then fixed to the heads of the soil nails. This installation process is repeated until the design wall depth is reached. The finished soil nails then produce a zone of reinforced ground.

Advantages

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 retainng walls
Allows excavation to start at the same time as the shoring system is being installed

Quality assurance

Keller has been installing and developing soil nailing techniques for many years. We use specialised equipment and experienced crews and employ strict quality control measures to ensure uniform and consistent results.