Abstract: Based on the research results of unsaturated porous medium, considering the influence of thermal effect and porosity fluid tortuosity, the propagation characteristics of thermoelastic wave in unsaturated soil are studied in this paper. The thermoelastic wave equations of the problem are established by the mass balance equation, seepage flow equations of continuity and momentum balance , and generalized non-Fourier heat conduction law of the solid-liquid-gas three-phase medium coupled with heat in unsaturated soil. By introducing the potential function, the dispersion characteristic equation of thermoelastic wave in unsaturated soil is theoretically derived. The variations of the wave velocity and attenuation coefficient of several types of thermoelastic waves with the thermophysical parameters such as tortuosity, thermal expansion coefficient and medium temperature, are analyzed in numerical examples. The results show that the increase of pore water tortuosity causes the decrease of wave velocity of P1 wave, P3 wave and S wave, while the increase of pore gas tortuosity only causes the decrease of wave velocity of P2 wave. The increase of thermal expansion coefficient causes the increase of P1 wave velocity and the decrease of thermal wave (T wave) velocity. The rise of medium temperature causes the increase of wave velocity of various thermoelastic waves. The variations of frequency, thermal expansion coefficient and medium temperature have a great influence on the attenuation coefficients of various thermoelastic waves, and these variations cannot be ignored.

Key words: unsaturated soil, thermoelastic wave, wave velocity, attenuation coefficient, propagation characteristics