Local modelling of backfill effects for rigid axisymmetric foundations under dynamic excitation

The influence of backfill on the dynamic response of rigid axisymmetric foundations is described as reaction of an independent layer. It leads to the solution of the kinematic interaction problem by means of the complex stiffness matrix of a supporting medium given by a specific increase in relation to the case of non-embedded foundations. The increases of stiffnesses are obtained in the closed-form from steady-state solutions to the equation of motion of an isotropic homogeneous medium under appropriate displacement boundary and radiation conditions. The approximate modelling is compared with results of the rigorous boundary integral equation approach.