SOIL NAILING-ALL YOU NEED TO KNOW

The soil nailing technique is used to reinforce soil to make it more stable. Added to that, it is used for slopes, excavations, retaining walls, etc. to make it more stable. This article will shed light on the soil nailing technique, its types and their applications.

Also, Soil nailing is a ground stabilization technique used to reinforce and strengthen existing ground. It can be used on either natural or excavated slopes.

It involves drilling holes for steel bars to be inserted into a slope face which are then grouted in place. It is economical and also applicable in seismic zones. Increases shear strength of overall soil mass and can be used in wide soil types.

Types of Soil Nailing techniques

The following sections present different types of soil nailing technique:

Drilled and grouted Soil Nailing method

• In this type of soil nailing methods, the holes are drilled in walls or slope face
• Then, nails are inserted in the pre-drilled holes.
• after that, the hole is filled with grouting materials such as concrete, shotcrete etc.
• Finally, diameter of nails ranges from 100-200mm with spacing of 1.5m.

Driven soil nailing method

• It is used for temporary stabilization of soil slopes.
• Driven soil nailing method is considerably fast.
• However, it does not provide corrosion protection to the reinforcement steel or nails.
• In driven soil nailing method, the nails are driven in the slope face during excavation.
• Diameter of the nail is around 19mm to 25mm which is comparatively small.
• Lastly, nail spacing is 1m to 1.2m.

Self-drilling Soil Nailing method

• Hollow bars are used in the self-driven soil nailing method.
• Bars are drilled into the slope surface. Grout was injected simultaneously during the drilling process.
• It is faster than drilled grouted nailing.
• Lastly, self-drilling soil nailing method provides more corrosion resistance to nails than driven nails.

Jet Grouted Soil Nailing method

• In jet grouted soil nailing method, jets are used for eroding the soil for creating holes in the slope surface.
• After that, steel bars are installed in this hole and grouted with concrete.
• Finally, jet grouted soil nailing provides good corrosion protection for the steel bars (nails).

Launched Soil Nail method

• In this method of soil nailing, the steel bars are forced into the soil with a single shot using a compressed air mechanism.
• The installation of soil nails is fast, but control over the length of the bar penetrating the ground is difficult.
• Utilized to reinforce an unstable or potentially unstable soil mass. capacity into the sliding soil.
• Finally, nail diameter is 38mm and its length is around 6m.

Advantages of soil nailing

• Suited for confined spaces with restricted access.
• Lesser environmental impact.
• Quick and easy to install.
• Uses fewer materials and shoring.
• Can be used on new constructions, temporary structures or on remodeling processes.
• Creates less noise and traffic obstructions.
• Less impact on nearby properties.
• Allows in-situ strengthening on existing slope surface with minimum excavation and backfilling.
• Can be used for strengthening of either natural slope, natural or manmade cut slopes

Disadvantages Of Soil Nailing:

1. Metal Soil nails can corrode easily.
2. Existing utilities in the soil can cause the problem in the soil nailing process
3. Soil nailing is not appropriate in a high water table area
4. It required skilled workers.

Application of Soil Nailing:

1. For slope stabilization.
2. Revamp existing retaining structures.
3. Reconstruction of existing retaining structures.
4. Roadway cuts.
5. Tunnel
6. Underbridge abutments.
7. Temporary excavation shoring.