TND Drilling offers various different methods and sizes of pile installations and design to best suit your site and requirements. Currently we offer pile depths to 20 metres and at a maximum diameter of 500mm.
TND Drilling has a range of piling rigs from mini piling digs up to 8 tonne machines. Our mini piling rigs are ideally suited to awkward spaces and smaller buildings such as extensions and garages, where deep piles are not required. Where a more substantial pile is required we have a larger machine that will handle the work.
The piling service that TND offer includes:
- Continuous Flight Augering (CFA) 200mm to 500mm diameter
- Retaining walls
- Pile design
Typical installations that require piling are large buildings, bridges, wind turbines, houses, garages, conversions, conservatories, swimming pools, basements and mezzanine floors.
The geology throughout the UK varies tremendously and for this reason there are numerous methods of piling, each better suited to specific geology.
Most common methods of piling
Continuous Flight Auger (CFA) Piles
Suitable for a range of soil conditions and work well in non-cohesive and water bearing soils such as sand, gravels and more solid materials such as clay. CFA Piles are made by drilling the auger into the ground using a hollow stemmed continuous flight auger; the auger is then drilled to the required depth or degree of resistance which is indicated by the pile design engineer. Once the auger has reached its desired depth the bottom cap is removed and concrete is then pumped down the centre of the auger. As the concrete is pumped through the centre of the auger it is slowly withdrawn, lifting the soil on the flights. Following removal of the augers, a complete tube of concrete will be left in the ground (the pile is formed then all that remains is to insert the steel pile cage).
Drop Hammer Piles
The drop hammer is a frequently used method for the installation of concrete piles. Drop hammers usually consist of a solid mass of forged steel ranging from 1000 to 5000 kg. The drops usually range from 0.2 – 2 m. Since the peak stress at the pile head can be greatly increased if the hammer strikes the pile centrally and at 90 degrees an, a long narrow hammer is preferable, as the blow will be more axial and has better impact characteristics.
Tubular Steel Piles
These piles are top driven to the required depth using a drop hammer or a hydraulic hammer; they are a very good design choice in ground conditions that are unstable and prone to collapse. If required the pile can be extended by drilling the centre out and continuing the pile to the required depth. The internal void can then be filled with concrete or grout if required, according to design. Normally the piles are driven open ended so that a soil plug is formed.