To install these piles few different methods are applied. Our company uses KELLY and CFA methods for the drilling piles installation.

KELLY METHOD

Using this method for the piles installation the drilling machines are used, in which the so-called KELLY equipment is mounted, consisting of a Kelly bar and a winch. A Kelly bar is a telescopic equipment consisting of several (2-5) telescopic sections. Depending on the bar rotation direction the sections can unfold or contract. One end of the Kelly bar is fixed with a rope to the winch, and an operating tool – an auger or a ladle – is fixed to the other end.

Applying the Kelly method, the piles may be installed using protective pipes or without using them. It depends on the ground characteristics, where the piles are being installed.

Using this method, we install piles with the diameter not more than 800 mm, and the length – up to 25 metres.

ADVANTAGES:

• Large pile diameter:
• Deep piles;
• Accurate cage layout.

DISADVANTAGES:

• low production rate;
• a site is soiled with the ground extracted.

CFA METHOD

Using this method for the piles, a hollow solid auger is drilled to reach the required depth, afterwards concrete is poured throughout the auger. The auger is extracted, and concrete fills the hollow cavity. After the auger having been extracted a steel cage is placed into concrete.

Using this method, we install piles with the diameter up to 750 mm, and the length – up to 14 metres.

ADVANTAGES:

• high production rate;
• additional protective pipes are not needed, for during the drilling process the bore walls are supported by the ground, which fills the auger;
• for the piles installation, which diameter is up to 600 mm and depth up to 14 metres, easily transported drilling machines can be used.

DISADVANTAGES:

• the concrete amount and its pressure have to be continually controlled, in order to avoid the hollow cavities;
• the position of a steel cage is not easily controlled;
• a site is soiled with the ground extracted.