Access to Various Piling Methods

SPEEDECK provide a design and install service for the following range of piles and piling techniques;

AUGERED CFA PILES

CONTINUOUS FLIGHT AUGER PILING TECHNIQUES

These piles are particularly economical and speedily installed choice of piling and can cater for a variety of ground conditions; sands, gravels and low-grade rock as this process requires no casings or drilling fluids.

Continuous flight auger piles are constructed by injecting concrete under pressure through the hollow stem of the auger, with the spoil being extracted in one continuous movement as the auger is withdrawn. After the pile head is cleared of debris steel reinforcement is submerged into the high slump concrete to form the pile.

ROTARY AUGER BORED PILING

CONSTRUCTION TECHNIQUE & APPLICATION

Rotary rigs create the pile bore by removing the soil in sections, approximately between 1-3 meters long, until the design depth has been achieved. At this stage full depth reinforcement cages, steel sections or permanent casings can be easily installed prior to the placement of concrete. Where piles are used for deep basements it may be permissible to leave the concrete at a low level in order to reduce pile breakdown.

In non- cohesive ground conditions, such as made ground and or granular layers, a steel temporary casing is screwed in to seal the top of the clay to prevent soil collapse or ground water inflow.

Rotary piling is generally used in dry stable soils and rocks.

RETAINING WALLS

SPEEDECK provide a variety of bored pile retaining wall solutions when provision for temporary and permanent support for basement excavations is required. We have the expertise and technology to ensure that ground movements are controlled and an economic solution is found.

The most common methods, secant and contiguous walls are discussed below. However further guidance and explanation of different techniques can be found in CIRIA guide C580.


SECANT WALLS

Secant piles are installed by overlapping reinforced male piles and female piles which are installed with a low strength gain concrete. They are adopted to restrict groundwater and fines inflow with retained heights of up to 8m common. Greater excavation depths may be achieved, however the geological and hydrological conditions need to be considered along with installation tolerances when determining the suitability of the application.

CONTIGUOUS WALLS

Contrary to their name, contiguous piles are actually installed with a gap of 100-200mm per pile. This means that the wall is not water or fines tight. Where the conditions allow, such as in cohesive soils, it can be the most economic form of retaining wall.

The choice of construction technique, CFA or Rotary, is dependent upon soil type but can range from 300-750mm diameter.

This can provide retained heights of up to 15m with propping and 10m in a cantilever situation.


ACCREDITATIONS