Rotary Bored Piling Rigs are a very prevalent machine throughout the construction industry, the majority of building and construction-related activities these days are performed using piling rigs. The machines are used to bore holes into the ground and are quite universal in the soil conditions they can be used on. Bigger than CFA Piling Rigs, the machines are agile and capable of clearing underground obstacles quickly.
What are bored piles and why do we need them?
Bored piles are cylindrical bodies made from concrete, wood or steel, that are installed into the ground in order to help support the load of structures built on top of them. When installed in rows or secant configuration they can form a supporting wall for an excavation or steep slope, or cut-off ground water. The length, diameter, material, geometry and layout of the bored piles can vary dependant on their intended use. Piles are inserted into the ground to offer the necessary support and stability when building homes, bridges and other structures on weak or granular surfaces.
In medieval Britain, piles were used for constructing foundations on weak soils near to rivers. Many villages and towns were located nearby to lakes and rivers for the availability of water. Therefore, weak bearing ground was reinforced by the use of timber piles that were manually driven into the ground.
How does the process work?
Rotary Bored Piles are built by rotating an encasing into the ground to support weak soil and then extracting the pile bore by means of an auger, bucket or coring unit connected to the machines telescopic Kelly Bar. The casing is used to give support to the pile through unstable ground and after the bore has been thoroughly cleaned to suitable depth, the pile is then inserted into the borehole and the casing is removed, leaving behind the finished pile. The purpose of piles is to make soil stronger so that it can easily support the weight of the structure that will be built above it. Boring is carried out to the designated depth by means of either a crane mounted or track mounted hydraulic drilling rig. Rotary Bored Piling technique can be used in almost all soil conditions— ranging from soft ground protected by provisional encasing to high grade, very hard rock cored into open-hole.
Rotary Bored Piling creates minimal vibration, which makes it perfect for use in areas that require a reduction in vibration and noise pollution such as urban locations. This technique has the advantage over CFA bored piles, in that they can be used in more variable and cemented rocks and soils and a number of different coring or digging tools may be used to overcome obstructions.
Advantages of bored piling
The are are a number of benefits to using Rotary Bored Piles including the variability of length and diameter, the low risk of ground heave resulting from pile installation and the minimal noise and vibration pollution. This method enables the borehole to be inspected before the placing of the piles, so the length, depth, shaft and base quality and verticality can be easily verified. Another advantage is the fact that this method offers minimal disturbance meaning there is limited risk of damage to the surroundings and adjacent structures. Rotary Bored Piling is sometimes favoured over CFA dependent on the project as there are no pile arisings to dispose of, making it quicker and more efficient for pile installation. A further advantage of this method is that with special tools the base of the hole can be reamed out to create a bell shape which helps to increase the bearing area of the pile, thus more weight can be supported.
Alternatively to Rotary Bored Piling, there are a number of other piling rigs that offer similar solutions such as CFA Piling Rigs and Mini Piling Rigs. The work carried out by these machines is a relatively similar process however they are more suitable for smaller jobs or in firmer ground conditions.
Omnia Machinery stock an excellent range of used Rotary Piling Rigs to suit many different projects from a range of leading manufacturers including Casagrande, Soilmec and Bauer. Our Rotary Piling Rigs range from depths of 10m up to 126m – we have a machine for most jobs! If you have any specific used construction machinery requirements, please contact us and our team of sourcing specialists will aim to procure the machine you are on the market for.