Bored/cast-in-place piles employing soil compaction of hole bottom, for the "Atommash" Plant

Conclusions

1. Compaction of the soil at the bottom of deep holes of 1-m diameter as described, raised the bearing capacity of piles at their ends, under the Volga-Don ground conditions, by three to five times.

2. In view of the fact that the toe of long (exceeding 15 m) floating bored/cast-in-place piles of usual construction contributed only to a weak extent (up to 10% of the total resistance, under Volga-Don conditions) to the performance of the pile, right up to its failure, it is expedient and economically efficient to install such piles only in holes previously rammed at their ends. Under ground conditions of type II in regard to collapsibility, this measure is particularly important in order to avoid inadmissible pile settlements resulting from negative friction following soil collapse under the weight of its own thickness. Cast-in-place piles placed in prerammed holes were introduced in the construction of Section 5 of the Volga-Don "Atommash" Plant, and are recommended for buildings of a substantial number of stories in Volga-Don.