Interface conditions modelling in computational limit analysis

In many geotechnical stability problems it is important to account for interface conditions between soil and structure, e.g. retaining walls and footings with no-tension contact. These interfaces can be considered as discontinuities in stress and velocity fields developed in the system undergoing plastic collapse. Discontinuous variable fields are often employed in FE lower and upper bound limit analyses to improve the performance of lower order elements used to obtain rigorous bounds on the collapse factor. Recently it was shown that these discontinuities can be conveniently represented by a patch of regular elements of zero thickness. This development opens the way for discontinuous LA formulations to be used with general yield criteria in both two-and three-dimensions to solve stability problems involving a wide variety of materials and interface conditions.