Foundations in trenches tamped into saturated clayey soils

Abstract

1. The method proposed for tamping makes it possible to construct trenches of a given shape and depth in saturated clay soils under separately standing foundations, even where the water table is situated at a depth 0.3–1 m from the graded surface of the ground. 2. The effective pressure on a bed for foundations with a flat lower surface in tamped trenches can be assumed equal to 0.3–0.35 MPa at which the settlement does not exceed 30 mm. 3. The tamping of a loose rigid material (gravel, crushed stone), and also a local clay soil with an optimum moisture content into the trench bed makes it possible to increase significantly the effective pressure on the bed and reduce the foundation settlements. 4. It is expedient to continue study of the method in question to investigate the effect of the shape and size of the tamper on the trench-tamping process under different soil conditions; the effect of the composition and quantity of material being tamped in on the shape and size of the distributing cushion and on the reduction in foundation settlements; the distribution of moisture and the density of the soil; and, the position of the water table in the beds of tamped trenches.