The main feature of this piling system is its ability to penetrate boulders and rock formations.  Socketing into hard rock is effected rapidly using the ‘Down the Hole Hammer’ (DTH) percussion drilling technique.  This pile is particularly suited to pile installation in Karst conditions present in the Dolomitic areas of Southern Africa.  It is also suitable for river bridge foundations subject to scour, where penetration through boulder horizons and socketing into bedrock is required.  The piles can be easily installed with a casing using propriety casing systems.  The casings can be permanent and incorporated into the pile design to ensure pile shaft integrity in cavity formations or moving groundwater conditions.  A range of pile sizes from 255mm to 610mm in diameter can be drilled with the equipment available in the Southern African region.  Diameters of up to 1000mm are possible using this technique, however, specialised equipment is required.

Positive Features

  • A good range of pile diameters is available for moderate applied loads
  • The ability to penetrate hard rock and boulder horizons
  • Rock-sockets can be formed relatively easily and economically
  • Casing installation associated with the DTH drilling technique provides high levels of pile shaft integrity
  • Noise levels are low and limited to the noise from the equipment
  • There is limited vibration associated with the DTH operation
  • Depths of up to 40 metres are possible