Vertical vibration of a rigid disc embedded in a poroelastic half-space in contact with a fluid half-space

This paper considers the problem of the vertical vibration of a rigid disc embedded in a poroelastic half-space in contact with a fluid half-space. A time-harmonic Green's function for a vertical point force in a poroelastic half-space in contact with a fluid half-space is first derived. The fundamental solution is obtained using the boundary conditions at the plane passing through the point force and the boundary conditions at the poroelastic medium-fluid interface. The solution of the disc vibration problem is obtained by integrating the point force Green's function over the contact area with unknown tractions, which are determined from the boundary conditions. The solution is expressed in terms of dual integral equations that are converted into a Fredholm integral equation of the second kind and are solved numerically. Selected numerical results for the vertical dynamic compliance coefficient are examined based on different poroelastic materials, embedment depth and frequency of excitation; moreover, the results are analyzed for two different cases, namely, with or without fluid overlying the poroelastic medium to demonstrate the effect of fluid. These results are helpful in understanding the dynamic response of foundations embedded in the seabed under seawater. (c) 2012 Elsevier B.V. All rights reserved.