Centrifuge modelling of footings on a finite soil layer underlain by a rigid base

Rough, circular, square, and strip model footings were modelled and tested in the University of New Brunswick's geotechnical centrifuge. These model footings rest over a limited soil cover underlain by a rigid boundary at a shallow depth. A monotonically increasing load was applied to the model footings, and the data on the bearing pressure and settlement were collected. The test program was completed for various soil depths relative to the width of the footing. The relative density of sand was also varied in the test program.; It was observed that the bearing capacity failure was local shear type, irrespective of the relative density of the sand layer. The experimental data obtained were compared to the data reported in the literature as well as theoretical predictions. Based on the comparison of the experimental results with the theoretical predictions, this study indicates that the theoretical methods are conservative for determining the ultimate bearing capacity. It also shows that the theoretical predictions for settlement are conservative for footings over dense sand, but under-predicts settlements for the loose sand.