Behavior of Model Circular Footings on Silty Soils with Cellular Supports

Abstract

An experimental study of the effect of silt and influence of cell confinement on the bearing capacity of circular footings on silty sand was carried out. Laboratory experiments on clean sand and sand containing silt up to 25 % were performed. Cells with different heights and diameters were used to confine the silty sand. The effect of proportion of silt in sand, cell diameter, cell height and the embedded depth of footing were studied. Initially, the response of a footing without cellular support was determined and then compared with that of footing with cellular support. The results indicate that the bearing capacity of circular footing can be appreciably increased by soil confinement. It was interpreted that such confinement resists lateral displacement of soil underneath the footing. It leads to a significant improvement in the bearing capacity of the footing. The cell–soil footing behaves as one unit for small cell diameters, while this pattern was no longer observed with large diameter cells. Results of model-scale footing tests show that bearing capacity decreases with fines. It is due to fact that on the increase of silt while density increases but increase in compressibility offsets the effect of density. The cell height, depth, and diameter that give the maximum bearing capacity improvement are presented and discussed.