A Study of Bearing Capacity by Centrifugal Footing Tests

A series of footing tests on sand have been carried out to study the effect of footing size, shape, embedment and relative density of sand on the bearing capacity for shallow foundation by centrifuge testing. The test results indicate that the failure mode changes from general shear failure to local shear failure and then to punching shear failure, and the relative settlement at peak bearing pressure iacreases obviously as footing width increases. The failure mode for an approximate strip footing on dense sand is typically general shear failure , whereas a punching shear failure mode results from a square footing on same density sand. The effect of footing shape on bearing pressure and failure mode is very significant. The initial slope of bearing pressure against relative settlement curve for a square footing is always much greater than that for an approximate strip footing. From the settlement profile below the footing and heaving on the soil surface outside the footing it can be seen that the angles between rupture and the horizontal surface of the sand are much greater than the theoretical value of (45°- φ2)A method to determine bearing capacity factors and shape factors using centrifugal footing test data has been suggested. The bearing capacity factors obtained by suggested method are compared with theoretical solutions and experimental data available.