Construction characteristics of pile foundation of reactor section of Kalinin nuclear power plant

Conclusions

• 1. For a close spacing of the piles in the pile field, around each driven pile the soil was loosened in a radius of 30–50 cm, and its bulging-out to a height of 40–80 cm occurred which led to general rise of the pit bottom. Below the bulging-out zone, soil compaction takes place, which makes difficult the further driving of piles.

• 2. Loosening and rise of the soil lead to superfluous labor in the restoration of the pit bottom design elevation, and it may cause additional settlement of the structure, since the load from it is taken not only by the mat but also partially by the piles.

• 3. Construction of the concrete bed with openings made it possible to substantially reduce the loosening and rise of the soil.

• 4. For elimination of the above-mentioned undesirable phenomena, it is necessary to increase the spacing between the piles to the value determined in the analysis. The experiments carried out at the project site showed that when the spacing between the piles is doubled, the pile driving operation is performed without difficulties, bulging-out does not occur, and the pile bearing capacity is preserved.