Every construction project has its own distinctive features, and depending on the type of soil, there are substantial differences in how the piling should be taken care of. With Junttan’s comprehensive experience and knowledge of a wide variety of piling applications, you can always count on getting the best possible solution for every situation.
In pile driving technology, a prefabricated, cut-to-size pile (precast concrete, steel, or wood) is lifted up and installed into ground by hitting the upper end with a hydraulic hammer. While making progress into the ground, the lower end of the pile displaces soil from around it.
Pile driving technology is known for being environmentally friendly. Thanks to the minimal hidden effects on the pile processing chain, the ecological footprint remains as light as possible. Prompt driving process without soil removal and minor need for assisting equipment further ensure both cost-efficiency and sustainability.
Driven pile with joint
In order to optimise the overall pile driving process, pile joints are used to reduce the length of an individual pile section. The joints can be either mechanical or welded. The Junttan pile driving rigs are famous for their high precision in pile handling, making the usage of pile joints exceptionally efficient – even with raked piles. Junttan also supplies special hydraulic attachments in their rigs to connect mechanical joints with ease.
Predrilled driven pile
Junttan pile driving rigs can be equipped with an additional side auger to perform predrilling. Predrilling is used to speed up the pile driving process when there is a very hard or dense soil layer covering the foundation site. Using predrilling not only protects the pile from too hard driving, but also efficiently minimises noise and vibrations.
A tube equipped with an extraction collar and a removable tip is installed into ground with a hydraulic hammer. As the target depth has been reached, the required reinforcement is installed. Then, fresh concrete is laid into the tube, which is then extracted with a specific extraction device. By utilising the tapping feature of the hammer, the concrete is compressed.
Junttan’s high-quality cast-in-situ rigs are able to provide outstanding stability. As the extraction strength needs to be substantial, reliable load control system is required. With Junttan paying close attention to productivity and reliability of the rigs as well as to safety at work, these features have been comprehensively taken care of.
CFA (continuous flight auger)
In CFA technology, the soil is continuously transported from the tip of the auger upwards
by the flights. The borehole is stabilised by the auger filled with soil. The use of a Kelly extension increases the drilling depth from 6 to 8 metres. Concrete is then pumped with the concrete pump through the hollow stem after reaching the final depth, while the auger is withdrawn. While pulling up, the flights are cleaned by an auger cleaner.
Displacement bored pile
In displacement bored pile technology, the operating pipe is put into ground by rotating it. While entering the ground, the tube removes soil from its way. As the tip of the pile reaches the target depth, the needed reinforcement is installed into the tube. Then, fresh concrete is laid into the tube. At the same time, the tube is gradually extracted. Concrete is added into the excavation so that it remains full. The reinforcement can also be pressed into the fresh laid concrete utilising a hydraulic or electric vibrator.
Large-diameter bored pile
In the Kelly drilling method, the starting point is the installation of a protective starter casing (length typically 6 m) or of a sectional drill casing with the rotary drive of the drilling rig.
After one cycle of the drilling and filling process, the drilling tool attached to the tip of the Kelly bar is withdrawn from the borehole together with the Kelly bar, and returned into the borehole after being emptied. The drill cycles are continued until the final depth is reached. The borehole wall is stabilised either by casing or by a stabilising fluid.
The reinforcement cage is installed into a cased borehole with a service crane or with the auxiliary winch of the drilling rig. Then concrete is placed by tremie method. The drill casing is then extracted with the rotary drive simultaneously with the concreting process.
Deep stabilisation technology
In deep stabilisation technology, highly stable ground mass is produced from the previously unstable material. Columns, groups of columns, or walls are formed at the desired depth by mixing in-situ material with one or several binding agents and fillers. Lime, fly ash, gypsum, and cement can all be used as binding agents, depending on the soil type and application method.