Elastic-Plastic Foundation Model for Punch-Shear Failure

A new foundation model which has been proposed in the literature, and which consists of two elastic spring layers interconnected by an elastic shear layer, is generalized herein to include the effect of plastic yielding in the foundation on the foundation response. By postulating an elastic-perfectly plastic constitutive relation for the shear layer, one obtains a model which simulates the punch-shear failures observed in highly compressible soils, a phenomenon not covered by the Prandtl type bearing capacity theory. For simplicity, the classical two-dimensional problem of an infinitely long rigid strip resting on the surface of the subgrade is treated. The effect of yielding on the load-deflection curve and contact pressure distribution is discussed. The theoretical results are in qualitative agreement with the limited available experimental data.