Soil Nailing

What is a Soil Nail?

Soil nailing is a ground stabilisation technique used to strengthen weak or unstable slopes, cuttings, and embankments, typically formed in soils such as clays, sands, and gravels. When correctly designed and installed, soil nailing helps prevent landslips and provides long‑term slope stability.

A soil nail generally consists of a steel bar installed into pre‑drilled holes and secured with cementitious grout. Soil nails do not work in isolation; they are installed in a predetermined grid pattern to create a reinforced soil mass. This reinforced zone increases overall shear strength and reduces slope deformation.

Soil nailing is widely used for slope stabilisation, retaining wall construction, cliff stabilisation, and infrastructure works, offering a safe and cost‑effective form of ground support.

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How does the process work?

At CAN Geotechnical, we have designed and delivered hundreds of soil nailing schemes, each tailored to the specific ground conditions and constraints of the site. A typical installation process includes:

Slope preparation, which may range from minimal works to de‑vegetation and re‑grading where required
Set‑out and access, with soil nail locations established by experienced engineers, often using rope access techniques
Plant and equipment selection, drawing on a wide range of drilling rigs that can be mounted on excavators, telehandlers, road‑rail vehicles, or specialist cable‑suspended A‑frames and slope rigs
Drilling and installation, most commonly using self‑drilling hollow bar systems, which allow grout to be pumped through the bar during drilling, with a sacrificial drill bit remaining in situ
Testing and facing installation, where a proportion of nails are load tested and appropriate facing systems are installed

Facing systems are typically flexible steel wire mesh, but may also incorporate erosion control matting where required. Load‑distribution plates are installed at nail heads, followed by perimeter wire ropes connected to the facing system.

System Variations

Depending on site conditions, soil nailing schemes may also incorporate additional stabilisation and drainage measures, such as:

Inclined drilled drains
Counterfort drainage systems
Crest‑line cut‑off ditches
French drains

While flexible facings are most common, some projects require rigid facing systems, such as sprayed concrete or stone‑filled basket systems. Each site is assessed on its own merits, with solutions tailored to achieve the most effective and durable outcome.