CONTINUOUS FLIGHT AUGER (CFA) PILES

This piling system is fast and economical. It has no vibration and limited noise levels.  However, it does have some limiting features.


Positive Features

  • High production levels are attainable in suitable soil conditions
  • The system is economical in suitable soil profiles
  • Noise levels are low and limited to the engine noise of the piling rigs
  • There is no vibration associated with CFA piles

Other Considerations

  • In sandy soils below the water-table there is a reduction in soil strength in the immediate vicinity of the pile due to the drilling operation.  As a result of this, the load / deflection performance of a CFA pile is inferior to that of a driven pile
  • Soil falling off the flight can contaminate the concrete / grout of the pile shaft
  • CFA piles have to be cast to ground level.  This results in waste of concrete and excess trimming if there are deep cut-off levels
  • There is very limited indication of soil strength during the drilling operation

The maximum depth of CFA piles is 30 metres at present and the recommended maximum rake 1:10.

CONTINUOUS FLIGHT AUGER (CFA) PILES TECHINICAL SPECIFICATIONS PDF