Vertical and Torsional Vibration of Foundations in Inhomogeneous Media

摘要

A study of the dynamic impedances for a radially inhomogeneous infinite viscoelastic layer with a circular hole, and for piles embedded in a medium represented by such layers is made. Systems in vertical and torsional modes of vibration are examined considering both a discontinuous variation in shear modulus and an exponentially increasing, continuous variation. The results are evaluated over wide ranges of the parameters involved and compared with those obtained for a homogeneous layer. In addition, the harmonic response of strip foundations supported at the surface of a vertically inhomogeneous viscoelastic halfspace is examined, and it is shown that within the framework of a previously proposed approximation, the impedances of such foundations for both horizontal and vertical modes of vibration may be deduced from those obtained for the vertically excited, radially inhomogeneous layer.