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Rotary Bored Piles

Bored piles are circular section reinforced cast in situ elements. A number of different drilling techniques can be used for their installation. Piles transfer structural loads from the surface to soil strata with good bearing capacity. When arranged in a line they can form a retaining wall for an excavation or a step in the terrain, or they can act as a barrier to groundwater. The length, diameter, and spacing of individual piles can be tailored to match the desired application. Depending on structural requirement, piles may be fully or partially reinforced. The most widely used method of constructing bored piles is rotary drilling.

The two main drilling methods are:

  • Conventional rotary bored piles using Kelly bar, augers and drilling buckets. Bores are supported during construction by temporary casing or a drilling fluid (such as bentonite, polymer or water).
  • Continuous Flight Auger (CFA). No temporary casing is used. Piles are concreted by pumping concrete through a hollow stem auger and reinforcement is placed after concreting.