GIKEN'S NEW Super Crush Piler recently made its European debut at a project in Blackheath, south east London. The system allows simultaneous augering and pressing in of sheet piles to cope with difficult ground.
Normally pre-augering is carried out in advance of sheet piling when the ground conditions require it. However in granular soils, reconsolidation after preaugering occurs fairly quickly.
Therefore it has to be done just in advance of the piling to be effective.
Simultaneous augering preaugers 500mm below the toe of the pile as driving progresses, so there is no opportunity for the soil to reconsolidate naturally before the pile is installed. As the auger is withdrawn it is 'back spun' deliberately to re-consolidate the disturbed material which reduces the impact on the nature of the soil.
The auger is encased in a tube which passes through the piler chuck. The tube ensures augering is in the desired place and provides the reaction force against which the auger-drive rotates.
The Super Crush Piler was used by main contractor Fitzpatrick to press sheet piles up to 3m in to Thanet Sands with SPT values of between 150 and 250 blows, to stabilise a slope and permit road widening.
Residential property at the top of the slope, combined with the extreme density of the underlying sands, made conventional installation methods too risky.
Giken says the piler allowed installation without noise or vibration disturbance.