Erosion Control Techniques: Soil Nailing

Soil Nailing

Have you ever been in a situation whereby you acquired a piece of land and people told you that you can’t erect any structure there because it is sloppy? Well, i would like to prove them wrong. Have you heard of Soil Nailing? Try Soil Nailing. This brings us to what soil nailing is.

Soil Nail Wall construction is a type of construction technique used as a corrective measure for undulating soil slopes whether natural or artificial to make the soil more stable. It is called soil nailing because it is like driving a nail into the soil where the nail in this circumstance is the steel bar which could be solid or hollow.

Soil nailing is used in sloppy areas, areas prone to landslides, excavated areas and areas with retaining walls to make them more stable. This type of construction technique requires the insertion of solid or hollow steel rebars into the soil or the slope.

Usually, holes are drilled, and solid bars are installed and then grouted into a place using a grout line, but hollow bars may be drilled and grouted at the same time with the use of a sacrificial drill bit and pumping down the hollow bar as drilling takes place. These bars are installed at an inclination of 10 to 20 degrees to the vertical.

Few Points to be considered in determining if soil nailing would be effective in that area are;

  • Ground conditions of that area should be examined.
  • Advantages and disadvantages for the particular application should be considered.
  • The cost of the soil nail walls should also be considered.

Points to Note during Installation

Immediately after excavation of any area, soil nailing should proceed as any slight delay may lead to the collapse of soil slope.

Strength of the soil should be determined because the spacing of the soil nails either in vertical or horizontal direction would be related to it.

For any edge of any surface being stabilized, extra soil nails should be installed.

You must make sure soil nails which are usually steel bars penetrate beyond the slip plane into the passive zone typically for 4m to 5m.

Types of Soil Nailing

Driven Nails

In this technique, the bars are hit in the slope face during excavation. This is a temporary stabilization technique for sloppy soils, and it is very fast. However, there is the probability of the reinforcement bars being corroded as it does not guarantee corrosion protection.

Launched Soil Nail

High speed compressed air mechanism is used to force the steel bars into the soil. The only downside to this method is that control over the length of the steel bar penetrating the ground is difficult.

Self-drilling Soil Nails

This technique is faster than grouted soil nailing and offers corrosion resistance to the bars. The bars used here are hollow and are drilled into the slope surface with grout being injected at the same time during the drilling.

Grouted Soil Nailing

Holes are drilled, and the bars either hollow or solid are inserted into the holes. The hole is then filled with grouting materials which could be a mixture of water, cement, and sand, shotcrete, etc.

Jet Grouted Soil Nail

Also, this technique offers corrosion protection for the bars. The sloped surface is eroded by using Jets and also for creating holes. Steel bars are then installed in this hole and grouted with concrete.

 

 

 

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