研究了双层非饱和地基中Rayleigh波（以下简称R波）的传播特性问题。首先将迂曲度引入孔隙流体的渗流连续性方程，对三相孔隙介质波动方程进行修正，接着采用体波的势函数之和构建各相介质的势函数，并借助Helmholtz分解，以及考虑土层边界条件和层间连续性条件，建立了R波的弥散特征方程，分析了饱和度、迂曲度和上覆土层厚度等参数与波速和衰减性的关系。结果表明，R波波速随饱和度的增加而线性减小；在渗透系数中间区段，则随着固有渗透系数? 的增大而增大；水力迂曲度?f对波速的影响主要体现在高频区段，而空气迂曲度?a的影响则非常有限；对于上软下硬地层，覆盖层厚度的增加将引起波速的减小，并逐渐趋于上覆土层本身的R波波速；且频率越高或表面层刚度越低，趋近速度越快。

This article investigates the problem of Rayleigh (R) waves propagation in double unsaturated soils. Firstly, wave equations of three-phase porous medium are extended by introducing the tortuosity of fluid phases into the conservation of momentum, then decomposed with the aid of Helmholtz theorem and the sum of potential functions of body waves. The dispersion equations are established with the boundary condition and the continuities of soil layers. The influences of saturation degree, tortuosity and cover thickness on the velocity and attenuation are discussed. The results show that the R wave velocity decreases linearly with the saturation, and increases with the intrinsic permeability ? in the intermediate range. The influence of tortuosity of water phase on R wave velocity is significant in high frequency domain. The tortuosity of air phase is negligible. For a ground system of upper-soft and lower-hard layers, the R wave velocity becomes smaller for thicker surface layer, and approaches the velocity in overlaying soil, especially for high frequency or surface layer with low stiffness.