The Overburden Drilling System is widely used from well drilling to mini-piling and rock anchoring to site investigation.
Amplus uses a two part Eccentric Overburden Drilling System designed for the simultaneous installation of casings to support unstable ground conditions and drill into rock.
The system can also be used with threaded and less expensive Welded Casings when the Casing is required to be left in the hole.
When the ODS has been drilled to the required depth, the Eccentric Bit can be closed to its concentric position, and the complete system withdrawn from the Casing.
If required, it is then possible to drill on into solid rock using a Conventional Button Bit.
The advantage of this system is its good value for money.
Please call Amplus to check whether ODS is suitable for your project.
CONCENTRIC OVERBURDEN DRILLING SYSTEM
A Concentric drilling and casing system such as Symmetrix is suitable for almost all ground conditions.
Reaming for the casing is carried out by a concentric ring bit.
Amplus drills the casing through the overburden and into the bedrock. Drilling is then continued with a normal down the hole hammer (DTHH).
The advantage of this system is it's speed and versatility.
Symmetrix drilling at Harbour Reach on the Waterfront in Jersey
CONTINUOUS FLIGHT AUGER (CFA) DRILLING SYSTEM
The Continuous Flight Auger method allows the construction of piles with minimal environmental disturbance. It is one of the quietest forms of piling, and is suitable for most types of ground conditions - it is particularly suited to interbedded sequences of clays and sands.
A hollow-stemmed continuous flight auger is rotated into the soil to the required depth using a top-mounted hydraulic motor - no casing is required. A high slump concrete mix is pumped down the stem of the auger and the pile is formed as the concrete is pumped into the pile bore whilst the auger is slowly raised, lifting the spoil on the flights. The rig is fitted with a comprehensive computer monitoring system.
Normal pile diameters of 300 mm to 900 mm can be constructed up to a maximum depth of 21 m. Depending on ground conditions, working loads of up to 2000 kN can be carried. Reinforcement placed by hand is generally limited to 12 m in depth, but longer reinforcement cages can be installed by vibrator