On propagation of normal waves in an isolated porous saturated by fluid Biot layer

For a porous saturated by fluid Biot layer with boundaries where stresses and pressure vanish wave field is established and dispersion equations are derived. The roots of the dispersion equation and the dependence of phase velosities of the normal waves on wave number are investigated by analytical methods. It is shown that the phase velocities of the most of normal waves decrease with increasing of the wave number. The special investigations are fulfilled in the case of the bend wave and the plate wave and their phase velocities on high frequences. It is shown too that on the boundary of the porous halfspace Biot the Rayleigh wave propagates not always and the conditions of its existence are established.