Strengthening the beds of foundations in tamped trenches by their preliminary surcharge

Conclusions

1. When foundations are installed in tamped trenches under especially complex soil conditions, it is necessary to:

• a) define the geologic-engineering make up of the site more precisely when performing experimental studies;

• b) conduct experimental studies on the tamping out of trenches, tamping in of a rigid material, and testing of foundations at 2–3 of the most characteristic points at which the maximum and minimum settlements and maximum bearing capacity are expected; and,

• c) focus special attention on the quality of work involving the installation of foundations, for example, on the cleaning of the trench bottom of soil that has fallen from its walls; the exclusion of the collapse of the trench walls, and the freezing soil; and ensuring that the foundations are concreted immediately after the trenches are tamped out and a rigid material has been tamped into them.

2. Preliminary surcharge of the foundations under a load equal to 0.7–0.9 of the design load will completely provide for their bearing capacity, corresponding to the design load with their subsequent settlement being 3–4 times smaller than the allowable.