PILETEC'S PILING SERVICES
We have many years of experience in completing piling work on projects of all sizes, in many ground conditions. Our expertise and competencies include Continuous (CFA) and Sectional Flight (SFA) auger piling, Rotary Open Bores, Odex piling and the highly versatile Grundomat piling. We offer expert consultancy and guidance to inform all decisions relating to the piling method chosen. Our efficient and collaborative site teams work accurately, effectively and cleanly, ensuring the rapid completion of piling works to all required standards whilst adhering strictly to all required health and safety standards.
TYPES OF PILING
SFA piles are formed by drilling multiple auger sections into the ground. The sides of the hole are commonly supported by temporary casing. Upon reaching the required depth, the augers are removed. The reinforcement is placed and cement grout or concrete is pumped from the base of the hole. The casing is immediately withdrawn.
Sectional flight auger
Controlled Tremie Grouting
CFA piles are formed by drilling a continuous flight auger into the ground. The sides of the hole are supported at all times by the soil-filled auger, eliminating the need for temporary casing. Upon reaching the required depth, sand-cement grout or concrete is pumped down the hollow stem as the auger is steadily withdrawn. Reinforcement is placed immediately after withdrawal of the auger.
Open Bored Piles are simply reinforced concrete piles cast in holes drilled to predetermined depths. While they probably are the most economical of all commonly used piles, their use is generally limited to certain ground conditions.
The ground formation in which the holes for open bored piles are to be drilled must be of such a nature that the drilled holes will retain their shape and will not cave in when concrete is placed. Because of cave-in and concrete placement difficulties, these piles are not recommended where groundwater is present, unless dewatering can be done without unreasonable effort and unless concrete can be placed without a casing having to remain in place.
This method loosens the soil by means of boring a hole of sufficient diameter through the difficult soil layers into which the pile must be installed. Pre-drilling is usually carried out by auger drilling. Pre-drilling may also be required on sites where it is important to avoid noise and vibration. Mechanical augers have been used to bore uncased holes to receive piles which are installed in the hole and then driven a short distance to their required bearing level. This method would only be used where cast-in-situ piles are unsuitable because of ground or structural conditions.
A limitation of pre-drilling is that the bearing capacity of the pile may be reduced due to decompression. This aspect must be taken into consideration when the load carrying capacity of the pile is estimated.
Odex Piling
The Odex Piling system utilises an eccentric under reamer to cut a drilled hole ahead of the bottom of the casing. The casing is then simultaneously advanced by a percussive force applied to bottom of the casing. As the hole is advanced, the drill cuttings are removed by air and travel up the inside of the casing in the annular space between the casing ID and the drill rod OD. The ODEX pile is highly effective in overburden soils where boulders or gravel layers are present, or when layers of rock must be penetrated. Generally the casing is removed once the pile reinforcement and concrete is placed. In some applications the casing is left in place while a rock socket is formed.
Super Jaws
A revolutionary new overburden system for simultaneously drilling and casing hole sizes 5-1/2″ to 42″ (139mm – 1067mm) in diameter.
Designed for top performance in both overburden and solid rock formations.
Large bit face area for transferring blow energy to the formation yielding faster penetration rates.
Uniquely designed bit wings extend out further than the casing O.D. when the bit reaches bottom to allow simultaneous drilling and casing.
The bit can be used to the full operating pressure of the hammer resulting in rapid penetration and minimum drilling time.
Bit wings retract inside the casing when the hammer is pulled off bottom. No reverse rotation, which can cause unscrewing, is required.
No ring bits or other drilling equipment is left down the hole.
Grundomat driven piles are extremely flexible. There are various hammers that offer a range of sizes and are able to accommodate even some of the most restrictive and difficult access points. This means that engineers and construction companies can benefit from being able to install high quality piles without the need for overly costly installation techniques. They are also very accurate and offer low vibration rates which mean that there is minimal displacement and piles are placed exactly where required with no guess work.
The flexibility of Grundomat driven piles lies in the fact that they can be used where other pile driving solutions simply cannot. Restricted access needn’t be a problem and this means that driven piles can be added in extremely hard to reach situations while still only requiring a small pile driving team consisting of 2 people.
The minimal vibrations and low noise mean that they can even be used in residential areas for the construction of extensions and conservatories on residential properties. Grundomat piles are also widely used on the railway infrastructure
Micropiles can be installed in areas of restricted access or close to buildings. Due to the fully threaded system, the micropile can be extended and grouted in areas where the founding level is deeper than expected.
The rotary percussive drilling method ensures minimal disturbance is caused during installation compared to driven piling systems, enabling the foundations of old structures or buildings to be upgraded without damage. Pile stiffness can be increased by placing a steel tube over the top 2m of bar and grouting the annulus.
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