A note on Rayleigh wave velocity in saturated soils with compressible constituents

The problem of Rayleigh waves in a semi-infinite saturated soil medium is reconsidered in this study, with the purpose of clarifying existing confusion and limitations of available studies. By employing Biot's general formulation, which takes into account not only the compressibility of the solid and fluid constituents but also the viscous dissipation due to fluid flow, the secular equation for Rayleigh waves is rigorously derived and the velocity of Rayleigh waves is computed for several typical types of saturated soils. The results show that the velocity of Rayleigh waves in general is independent of frequency in the frequency range actually employed in engineering practice and is only slightly less than the shear wave velocity. The results confirm that current understanding of Rayleigh wave velocity achieved based on the classical theory of elasticity is acceptable and indicate that some results in the literature are incorrect