Self-drilling anchoring is an efficient support system that serves as a means of reinforcing soil to make it more stable. Essentially, it is used for deep excavations; strengthen existing retaining walls, instable slopes and more, with the sole purpose increasing stability.
In this method, Hollow threated bars are driven into the all type of soil/overburden and grout can be injected through the hollow bar simultaneously during the drilling. The hollow-core bar is fitted with an over-sized, sacrificial drill bit that has two to five holes to allow grout to pass through. The bar is rotated and advanced with a percussion hammer. Grout pressure then forces the grout back along the outside of the bar to the ground surface. When the bar reaches the target depth, both the drill bit and bars are left in the hole to serve as the soil nail reinforcement.
The main design philosophies behind self-drilled anchor were to allow easy installation particularly in collapsible strata to minimize ground disturbance and to enhance the soil around it to allow the maximum soil strength parameters to be utilized. This method is faster than the grouted nailing and it exhibits more corrosion protection than driven nail.
- A high rate of installation since drilling, placing and grouting can be performed in a single operation.
- Self-drilling system eliminates the requirement for a cased borehole.
- There is minimal loss of shear resistance due to soil remoulding.
- Slope stabilization
- Strengthening of existing retaining wall
- Applied in conjunction with high tensile wire mesh to prevent falling of rock blocks.