An efficient approach for dynamic impedance of surface footing on layered half-space

A semi-analytical model for the evaluation of dynamic impedance of rigid surface footing bonded to multi-layered subsoil is proposed. The technique is based on the dual vector form of wave motion equation and Green's influence function of subdisk for horizontally layered half-space. The multi-layered half-space is divided into a quite large number of mini-layers and the precise integration method (PIM) is introduced for the numerical implementation. The PIM is highly accurate for solving sets of first-order ordinary differential equations with specified two-end boundary conditions. It can produce numerical results of Green's influence functions up to the precision of computer used. The dual vector form of wave motion equation makes the combination of two adjacent mini-layers/layers very easy. As a result, the computational effort for the evaluation of Green's influence function of the multi-layered half-space is reduced to a great extent. In order to satisfy the mixed boundary condition at the surface, the footing–soil interface is discretized into a number of uniformly spaced subdisk-elements. Comparisons illustrating the efficiency and accuracy of the proposed approach are made with a number of solutions available in the literature.

Figure optionsDownload as PowerPoint slideHighlights
► A new approach for the dynamic response analysis of 3-D footing–soil interaction.
► The soil can be half-space or multilayer soil.
► PIM can solve problem with less calculated effort, while achieving higher accuracy.
► PIM can avoid the index overflow problems of transfer matrices method.
► No limitation is imposed on the thickness of the layer for the new approach.