A Model of Energy Dissipation for the Mode of Rupture of Shallow Foundations in Sandy Soils

The plastic deformation of sandy soils is poorly understood from a microscopic point of view. The criteria to predict the mode of rupture of shallow foundations are mostly based on phenomenological arguments and may fail to explain the results obtained experimentally in model foundations. This work validates a model to determine the mode of rupture of sandy soils underlying shallow foundations based on the assumption that the complex rupture behavior of sand may be described approximately as a trade-off between the energy dissipation in a sand slip and the subsequent reduction of elastic potential energy in the surrounding sand mass. This theoretical framework describes more accurately experimental results found in the literature than the approach based on the rigidity index of the soil. In order to extrapolate results from small-size model experiments to large-size foundations, direct dimensional arguments may be used, since the proposed account of the failure mechanism is based on the laws of mechanics, not on phenomenological equations.