Response of poroelastic halfspace to steady‐state harmonic surface tractions

Abstract Traditionally, most formulations of dynamic halfspace problems have represented the material as either an elastic or a viscoelastic solid. Herein the counterpart of Lamb's elastodynamic problem is reformulated and solved for a liquid‐saturated poroelastic halfspace using Biot's theory of poroelasticity. The responses of the solid and fluid phases are evaluated due to steady‐state harmonic concentrated loads applied to each phase at the surface. The solutions are presented over a broad range of permeabilities and are compared to solutions to Lamb's problem for equivalent drained and undrained solids. Methodology is then introduced by which these results are treated as Green functions for the solution of a mixed boundary‐value problem. namely, the response of the poroelastic halfspace to steady‐state harmonic vertical motion of a rigid. massless plate. It is observed that small differences exist among overall compliance functions for a drained solid, an undrained solid, and a liquid‐saturated porous, halfspace. However, use of the poroelastic model permits the distribution between effective skeletal normal stresses and fluid stresses to be determined.