Dynamic analysis of axisymmetric foundations on poroelastic media

A boundary element method (BEM) is presented for the dynamic analysis of axisymmetric poroelastic media, subjected to time-harmonic excitation. The integral formulation, based on the fundamental solution of Biot's poroelastic theory, eliminates the need for domain discretization for piecewise homogeneous media and automatically satisfies the radiation conditions. Additionally, there is no special treatment required for the incompressibilty that may result under undrained conditions. The axisymmetric formulation that is developed offers further reduction in dimensionality of the problem and provides a convenient framework for investigating the behavior of circular foundations. The BEM algorithm is validated via comparisons with an analytical solution for the dynamic response of a soil column under uniaxial loading and is then utilized to study the dynamic compliance of a shallow circular foundation. The suitability of employing various quasistatic and elastodynamic idealizations is considered in some detail.