Normal waves in porous layer with opened pores on one boundary and with closed pores on other boundary

Isolated porous Biot layer with opened pores on one boundary and with closed pores on other boundary is considered. In this layer normal waves are investigated. For them dispersion curves are established. The low-frequency and high-frequency are analyzed explicitly. In low-frequency the plate wave is unique in this layer. In high-frequency the normal waves correspond to Rayleigh waves propagating along free boundary of porous media. The velocity of these Rayleigh waves in the case of opened pores is greater than the velocity of Rayleigh wave in the case of closed pores.