Torsional oscillation of a rigid disc resting on an infinite saturated elastic layer

A study is made on the forced torsional oscillation set up in an isotropic, homogeneous, saturated elastic layer by a rigid disc attached to the free surface of it. The behavior of the saturated layer is governed by Biot's theory and its governing equations are solved by means of Hankel transforms. Based on the assumption that the contact between the disc and the layer is perfectly bonded, this topic can be reduced to dual integral equations, which are further reduced to Fredholm integral equations of the second kind and solved by numerical procedures. The numerical examples indicate that the material and geometrical properties of the layer, the exciting frequency and different boundary conditions at the base of the saturated layer affect the dynamic behavior of the rigid disc, which significantly differs from the corresponding results of a homogeneous saturated half space.