A DPA pile (Drilled Pile Atlas) is a screwed-in displacement concrete pile in which a special screw point pushes the soil sideways without removing it. The pile is formed in place: once the design depth is reached, the screw is withdrawn step by step while concrete is pumped into the void it leaves behind. This produces a low-vibration and low-noise pile.
How does the system work?
The installation of a DPA pile follows several steps:
- Screwing in — a special screw point (the Atlas head) is driven rotationally and downward into the soil
- Soil displacement — the screw point pushes soil sideways without producing spoil
- Reinforcement cage — once the design depth is reached, a reinforcement cage is set in the casing
- Concrete placement — as the tool is withdrawn step by step, concrete is pumped into the void under pressure
- Lost point — the screw point remains as a lost end below ground
Features
- Soil displacing — no spoil to dispose of
- Low vibration — suitable for inner-city sites and next to existing buildings
- Low noise — particularly valuable in residential areas
- High capacity — the densified soil around the pile gives good load capacity
- Diameter — typically 360–560 mm
- Length — up to around 25 m
Applications
DPA piles are mainly used for:
- Urban construction — where low-vibration piling is required
- Renovation and extensions — next to existing foundations
- Soft soils — where conventional driven piles are not permitted because of adjoining buildings
- Sites near monuments — to avoid damage to neighbouring buildings
Points to watch
- Soil investigation — a CPT survey is needed to define the pile length
- Specialist installation — only by qualified contractors
- Cost — more expensive than driven precast concrete piles
- Speed — slightly slower than driving
Related terms
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