Technology of the device of stuffed piles. 1. Kinds of stuffed piles and technology of their device.

Rammed piles are arranged at the place of their future position by filling the well (cavity) with concrete or sand. Currently, a large number of solutions for such piles are used. Their main advantages are:

■ the ability to manufacture any length;

■ lack of significant dynamic effects when installing piles;

■ applicability in cramped conditions;

■ applicability for strengthening existing foundations.

Ramming piles are made of concrete, reinforced concrete and soil, and there is the possibility of piles with a wider heel. The method of piling is simple - in the pre-drilled wells is fed to fill the concrete mix or soil, mainly sand.

The following types of stuffed piles are used - Ostrich piles, bored, pneumatic-type, vibro-rammed, frequency-rammed, vibro-abrasive, sandy and soil-concrete. The pile length reaches 20 ... 30 m with a diameter of 50 ... 150 cm. Piles manufactured using installations made by the companies Kato, Benoto, Liebherr can have a diameter of up to 3.5 m, a depth of 60 m, a bearing capacity of up to 500 tons.

Bored piles. A characteristic feature of the device bored piles is pre-drilling wells to a predetermined depth.

The first in our country, on the basis of which all existing types of bored piles are applied, are the Ostrich piles, which were proposed in 1899. The manufacture of piles includes the following operations:

■ well drilling;

■ lowering the casing into the well;

■ extraction of loose soil from the well;

■ filling the well with concrete in individual portions;

■ tamping concrete with these portions;

■ gradual casing removal.

Drilled to the design mark (5 ... 12 m), the well is carefully lowered into a pipe with a diameter of 25 ... 40 cm and then loaded with concrete. After filling the well to a depth of about 1 m, the concrete mix is ​​rammed and slowly lifts the casing up until the height of the mixture in the tube decreases to 0.3 ... 0.4 m. The concrete mix is ​​loaded again and the process repeats. Considering that the diameter of the well is larger than the diameter of the casing and the surface of the drilled soil turns out to be uneven, rough, when the casing is filled with concrete, it is raised and the mixture is compacted, the concrete will fill the entire free volume, including the gap between the walls of the well and the casing. Part of the concrete and cement milk will penetrate into the soil, increasing its strength.

The disadvantages of the method is the inability to control the density, and the solidity of the concrete over the entire height of the pile, the possibility of erosion of non-set concrete mix with groundwater.

Reinforcement of piles is carried out only in the upper part, where metal rods are installed in the newly laid concrete to a depth of 1.5 ... 2.0 m for subsequent communication with the grillage.