Soil Nailing Installation

Soil nailing is an earth retention technique which uses grouted tension-resisting steel Anchors or fibreglass reinforced nails

Soil nails can be employed for permanent or temporary support.

Soil nailing is a specialist technique for earth retention, erosion control, stabilising soil slopes, construction areas, tunnels, deep excavation cuts, and repairs to existing structures.

Soil nails are a strong and reliable solution to soft, unstable slopes. Used in conjunction with TRM (erosion matting), soil nails can stop loose soil from shifting and prevent further erosion. This is crucial for infrastructure and civil construction projects within a strict timeline or contract.

To be 100% effective, soil nail installation must be executed by fully trained and experienced ground stabilisation staff.

Ground Stabilisation Systems is one of Australia’s most experienced ground engineering specialists utilising numerous specialist Techniques.

Highly regarded for our geotechnical services and engineering solutions for commercial, civil, mining, and construction industries, we will approach your project with expertise and professionalism.

Contact us for more information about our soil nail installation services.

How does it work?

Soil nailing uses materials like steel anchors, fibreglass, and hollow bars to penetrate the surface and stabilise slopes. It provides strength and retention to soft soil and also promotes regrowth in those areas.

We only use the highest-quality soil nails and utilise the latest innovations in ground stabilisation for the installation process. Detailed investigation and planning, along with the latest technology, ensure that every project provides a stable, long-term solution to even the most demanding slopes and unstable sites.

Soil nailing equipment can be small enough to negotiate areas with restricted access. For existing steep slopes, the soil nails can be installed from telehandlers/EWPs and crane-suspended working platforms, as well as positioning man portable drills with helicopters. Soil nails can also be installed directly beneath existing structures adjacent to excavations and used to stabilise retaining walls or existing fill slopes.

Care should be exercised when applying the system underneath an existing structure. Ground Stabilisation Systems uses extensive 3D modelling to avoid conflicts between soil nails and other earth retention systems on complex projects involving multiple techniques. This also ensures the safety of buried utilities in urban environments.

 

Considerations: ground conditions, budgets, and ground stabilisation systems

Some investigation and analysis are required to determine whether permanent soil nails are the right solution to your ground stabilisation problems. Considerations include:

  • The condition of the ground
  • The suitability of other systems, like ground anchors and geosynthetic materials
  • Costs and budgetary requirements.

While soil nails are versatile and can be used for various soil conditions, Soil types like clay, glacial soils, sand, and gravel are well-suited for many other ground conditions.

Soil types with a high groundwater table, soft fine-grained soils, corrosive soils, loose granular soils, and ground exposed to repeated freeze-thaw action are generally unsuited for soil nail installation.

For the team at Ground Stabilisation Systems, we will also need to consider the design and the capability of soil nails to complete the task at hand. These considerations include:

  • Ground properties and soil type
  • Nail length, diameter, and maximum force
  • The inclination of the soil nails
  • Vertical and horizontal spacing of the soil nails
  • The strength limit, i.e. where potential failure or collapse could occur
  • Drainage
  • Wind and hydrostatic forces.

Pros & cons

There is a wide range of benefits to soil nail installation:

  • The equipment is small enough to use in areas with restricted access. Soil nails can even be installed from crane-suspended working platforms for steep slopes like bluffs and existing failing retaining walls.
  • Soil nails are a fast and cost-effective solution for excavation support. Generally, a soil nail wall is more economical than a concrete gravity retaining wall or reinforced ground anchor wall.
  • Soil nails are less disruptive to certain traffic footprints and have a smaller environmental impact than other construction techniques.
  • Soil nail walls are flexible and can accommodate differential movements. They have also performed well during seismic events like earthquakes.

However, even the most effective system has its limitations. For soil nail installation, these include:

  • Utilities behind the soil nail wall will restrict the location, inclination, and length of the soil nails. This includes some kinds of communication lines, like optic fibre, running adjacent to the soil nails.
  • Soil nails are unsuited to areas where large amounts of groundwater seep into the excavation. Soil nails require a temporarily unsupported excavation face during construction.

FAQs

What are pre-drilled holes and bearing plates? Why are they essential in soil nailing?

Pre-drilled holes are created using specialised equipment to ensure accurate placement of the soil nails within the slope or excavation face. They help maintain alignment, control depth, and avoid conflicts with underground services. Precise pre-drilled holes are essential for achieving optimal nail performance and ground stabilisation.

Bearing plates are steel plates placed over the nail head and secured with nuts to distribute the load across the wall face. They help resist external loads acting on the retaining wall, increase face stability, and provide structural support for any flexural system or fixed reinforced system, such as reinforced shotcrete.

Can soil nails be installed during underground excavations?

Yes. Soil nailing is often used in underground excavations to stabilise tunnel portals, access shafts, or deep cuts. The technique is effective in confined spaces and can be used with reinforced shotcrete to form a secure wall lining during and after excavation.

How do soil nails handle external loads from buildings or roads?

Soil nails can be designed to withstand significant external loads, including those from adjacent structures, traffic, or construction activities. Through detailed modelling and analysis, GSS engineers determine the optimal nail length, diameter, inclination, and spacing to safely resist these loads.

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At GSS, we pride ourselves on our certified management systems, as supported by the standards and awards we have achieved. Our focus is on delivering the highest quality ground engineering services for every project we undertake. To achieve this, safety and efficiency are at the forefront of all operations that GSS are involved in.

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