- A drilling method is determined.
The drilling method will depend on the soil profile. Whilst a good soil investigation report will help decide on the drilling technology it is the piling contractors experience which will determine the geologically specific tooling best suited to minimize disturbance of the surrounding soil and deliver the most cost-effective outcome through increased penetration rates.
- A void is formed by boring before a pier is produced.
A conventional auger is attached to a shaft and rotated under pressure to dig into the soil. When the auger flights are filled with soil, the auger is raised above the ground and emptied to form a shaft (drilled shaft).
- Expecting the unexpected
When we encounter rock it’s not until a borehole is begun that we can properly assess the density and consistency of the formation to then be able to work out the rate of penetration and select the tooling most suitable to form the shaft.
- Once the shaft has been drilled, a pier casing may need to be installed.
We can construct bored piers both cased and un-cased and can also offer the use of temporary pile liners where necessary. A pier casing is often required in more challenging conditions where granular soils or groundwater are present. The casing provides superior resistance to soil collapse in such unstable conditions.
- Next a large diameter concrete cylinder is constructed
This is done by placing reinforcing steel and fresh concrete into the drilled shaft.