Impacted piles, flushed and vibrated
In practice, driven piles have found wide application, which are made of wood, steel and concrete (reinforced concrete, compressed).
Wooden piles. The main condition for the use of wooden piles is their permanent depression below the groundwater level. With changing groundwater levels, these piles quickly deteriorate.
The best piles are made of pine wood. Oak is good, because it becomes very hard under water, but it is expensive. Spruce piles are also made, fir and other trees.
The piles are made of debarked straight fiber logs, equal or even, no knots and no major cracks.
Wooden piles with blades and fittings: a) view, b) blades and fittings.
Pile dimensions: length 4.0-10.0 m (most 12,0 m), diameter 20-25 cm for piles of length 4,0 m, 30-35 cm for longer lengths.
Steel piles. Steel piles are then used, when there is a need to break into the rock to a great depth. These piles are made of steel pipes concreted. Steel pipes with an open bottom or I-section are driven into the ground. After the pipe pile reaches the rock or shows more resistance when driving, they are cleared of soil, which got inside the pipe and concretes it. Cleaning inside the pipe is usually done by blowing with compressed air or by using pressurized water.
Concrete and reinforced concrete piles. Concrete and reinforced concrete piles can be divided into two main groups:
a) prefabricated piles,
b) hammered piles, i.e. made on site in the ground.
Prefabricated piles are made of reinforced concrete or prestressed concrete on a training ground or in a prefabrication plant and are driven into the ground in various ways, most often by hammering.
Driven piles are made of concrete or reinforced concrete. Concrete is laid immediately in the ground at the destination, in a hole made with a casing pipe (cladding), and sometimes without it. These piles are easier to build than prefabricated piles. The production of driven piles takes place simultaneously with their sinking into the ground at the place of destination, while prefabricated piles are made in two stages, at the prefabrication plant and at the destination site.