Waves in Partially Saturated Medium Due to Surface Loads

Abstract

A two‐layered continuum in which the underlying half‐space is a fluid‐saturated porous (two‐phased) medium is considered. A comprehensive analysis is made of the disturbance produced in this continuum by time harmonic normal point loads acting at the surface. Integral solutions for the surface displacements are derived. Viscoelastic‐type behavior is assumed for the layer, while the behavior of the half‐space follows Biot's small strain theory for poro‐viscoelastic media. Attenuation of the dilatational and the shear waves in the layer and in the skeletal frame of the fluid‐saturated porous half‐space is assumed. Although the numerical applications presented are restricted to hysteretic attenuation, general‐type, frequency‐dependent attenuation models can be also employed by taking advantage of the frequency‐wave number domain formulation presented. In addition, dissipation due to viscous resistance of the pore fluid is included in the solution. Plots are displayed showing comparisons with conventional solutions for “dry” cases. In these plots, the influence of the pore fluid on the wave propagation is shown.