Analysis of propagation characteristics of Rayleigh waves in saturated porothermoelastic media

Based on the theory of porous media and the generalized thermoelasticity model, the propagation characteristics of Rayleigh wave (R wave) in saturated porothermoelastic media are studied in this paper. A thermal-fluid-solid elastic wave coupled model of saturated porous medium is established by considering the fluid-solid coupling wave equations for saturated porous medium, continuity equation and the generalised thermoelastic basic equations. By introducing the potential function and combining the boundary conditions of free water permeability and adiabatic, the diffusion characteristic equation of R wave in saturated porous thermoelastic medium is derived theoretically. The effects of thermophysical parameters such as porosity, permeability coefficient, thermal expansion coefficient, initial temperature and relaxation time on the wave velocity and characteristic attenuation of R wave are analyzed by numerical examples. The results show that the increase of porosity causes the decrease of R wave velocity, but results in an increase in its characteristic attenuation. With the increase of the permeability coefficient, the R wave velocity first remains constant, then increases sharply, and finally stabilizes; and its characteristic attenuation first increases and then decreases, and finally tends to be stable. The increase of thermal expansion coefficient causes the increase of R wave velocity, but has no effect on the characteristic attenuation; the increase of initial temperature leads to slight increase of R wave velocity, but has little impact on its characteristic attenuation; the relaxation time has almost no effect on both the velocity and the characteristic attenuation of R wave.