非饱和土中热弹性波的传播特性分析

基于非饱和多孔介质的研究成果,考虑热效应和孔隙流体迂曲度的影响,研究了非饱和土中热弹性波的传播特性。利用非饱和土中耦合热的固-液-气三相介质的质量平衡方程、渗流连续方程、动量平衡方程和广义非Fourier热传导定律,建立了问题的热弹性波动方程。通过引入势函数,经过理论推导给出了非饱和土中热弹性波的弥散特征方程。结合数值算例,分析了几类热弹性波的波速和衰减系数随迂曲度、热膨胀系数和介质温度等热物理参数的变化规律。结果表明:孔隙水迂曲度的增大将引起P₁波、P₃波和S波的波速增大,而孔隙气体迂曲度的增大仅使得P₂波的波速增大;热膨胀系数的增大将造成P₁波波速的增大和热(T)波波速的减小;介质温度的升高将引起各类热弹性波波速的增大;频率、热膨胀系数和介质温度的变化对各类热弹性波的衰减系数均有较大影响,不可忽视。

Propagation characteristics of thermoelastic wave in unsaturated soil

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.