Mini piles are installed by forming a pre-bored hole in the ground with a socket in rock using light hydraulic drilling rig. A permanent steel casing will be installed to support the unstable strata and ensure safe working conditions on ground / working platform. “Overburden drilling method” (down-the-hole hammer technique) will be adopted for sinking the pre-bored hole. This technique is suitable for variable ground conditions including boulders and hard rocks.
Subsequent to the pre-boring, the following processes will be followed.
- Air-lifting and pile base cleaning,
- Installation of steel reinforcement bars,
- Backfilling the bored hole with non-shrink cement grout by tremie method.