Analysis of a circular raft in adhesive contact with a thick elastic layer

The problem considered is that of a circular raft of finite flexibility in adhesive contact with a thick isotropic elastic layer underlain by a rigid base. The applied load is assumed to be either uniform or to vary parabolically from a maximum at the raft centre to zero at the edge. Using the displacement finite element method, solutions are obtained for a homogeneous layer, and also for one particular form of linearly heterogeneous layer. Eight-noded isoparametric elements are used, and the accuracy of the numerical solution is shown to be adequate, provided that certain simple procedures are followed. For rafts on clay, the computations indicate that interfacial adhesion can significantly reduce the consolidation component of differential raft displacement, although, in practice, interfacial slip is likely to diminish this effect. It is shown that differential raft displacements are rather sensitive to the distribution of applied load when the soil is strongly heterogeneous; in particular, the general ...