Application of Soil Nails
Application of Soil Nailing process is preferably for support excavation, hill cuts, bridges and highways. Considering the most important things for the implementation of the process is that to start at the top and while taking the dig, wall should be extended on lift and depths. Soil nailing can be an option for this problem listed:
Stabilization of ground slope
Repair and reconstruction for infrastructures
Installation of Soil Nail
The Construction procedure starts on drilling the soil, locate the nail and steel bar target points. And after drilling has been done the nails must be inserted on holes. Then, the grout take place into the soil to develop a structural member. Then, on some cases shotcrete is constructed with wire mesh or any other reinforcement placed on a soil surface to protect the soil. And often used for aesthetic structure finishes.
Soil Nail Construction Sequence:
Excavate soil cut
Drilling of nail holes
Install soil nails and grout
Shotcrete installation for soil surface (optional)
Construction from top-bottom sequence
Provide final facing for aesthetic
Advantages of Soil Nails
Soil Nailing has many advantages compared to any other ground improvement techniques. Some of this advantages are enumerated below:
It can manage to work for a less space area.
Less damage on other structures within the vicinity
More cost efficient
Can be used for temporary constructions
Reduced inconvenience such as road traffic
Disadvantages of Soil Nails
Some of the disadvantages of soil nails are:
Soil nails are not applicable for large amount of groundwater seeps on excavation.
Permanent long term applications are not recommended.
Sand and gravels are not compatible on this process.
Not practical to use on areas with a high water table.
Soil Nail Techniques Process
Soil nailing used materials such as reinforcing bars and grout installed with an inclination of 10 to 20 degrees to the vertical. Here are some commonly used soil nail process:
Drilled and grouted soil nailing method
Wherein holes are drilled on a slope surface then nails with a diameter of 100-200mm spaced 1.5 meters on center are inserted on holes with grout.
Driven Soil Nailing Method
Commonly used for temporary stabilization, it is fast. however, it does not provide corrosion protection to the steel or nails. Diameter of nails are around 19mm to 25mm spaced at 1 meter on centers.
Drilling Soil Nailing Method
Hollow bars are used in this method, bars are drilled and grout is injected, typically faster than driven nails.
Jet Grouted Soil Nailing Method
It is used for eroding soil for creating holes in the soil surface, steel bars are installed in this hole and grout with concrete.
Launched Soil Nailing Method
In this method soil nailing steel bars are forced to the soil with a single shot using compression by an air mechanism. It is fast. Good on sliding soil conditions. Soil Nail diameter is 38mm and its length around 6m.
Consideration on Soil nailing
Soil nails must penetrate beyond the slip plane, the spacing of soil nails on grid pattern must be related to the soil strength and bearing capacity. The construction must be monolithic any delay may cause danger on slope stabilization.