Vertical and Torsional Impedances for Radially Inhomogeneous Viscoelastic Soil Layers

摘要

A study of the dynamic impedances of thin, infinite viscoelastic soil layers with a circular hole is made considering a continuous, ramp-like radial variation for the shear modulus of the material. Both vertically and torsionally excited systems are examined. The impedances are evaluated over wide ranges of the parameters involved and compared with those obtained both for homogeneous layers, and for inhomogeneous layers with discontinuous variations in shear modulus. In addition, a simple approximate method of analysis based on the Galerkin approach is presented for vertically excited layers, and it is used to assess the parameters that control their high-frequency response.