地球表面绝大部分土层并非处于完全饱和状态,故采用传统的饱和土两相介质理论进行动力学分析时,计算结果往往与实际情况不符。针对这一客观问题,以非饱和土为研究对象,在三相孔隙介质波动理论的基础上开展了非饱和土体半空间中Rayleigh波的弥散特性研究。分别考虑了两种不同的边界条件:(a)不透水不透气地基边界;(b)透水透气地基边界。根据边界条件及相关的本构关系式,推导出相应Rayleigh波的弥散方程,再通过Newton-Raphson法进行数值求解。最后讨论了在不同边界条件下,非饱和土地基表面附近Rayleigh波的弥散特性受到地基土饱和度、频率以及土体固有渗透系数的影响。计算结果表明:在两种边界条件下Rayleigh波的传播均受到地基土饱和度变化的影响。并且,频率及渗透系数在不同边界条件下对Rayleigh波特性的影响明显不同。 Most of the Earth’s surface layer is not in full saturation state, so the traditional saturated soil two-phase medium theory for dynamic analysis, the calculation results are often inconsistent with the actual situation. In view of this objective problem, taking unsaturated soil as the research object, the dispersion properties of Rayleigh waves in unsaturated soil half-space are studied based on the three-phase porous medium wave theory. Two different boundary conditions are considered separately: (a) the impermeable impervious foundation boundary; and (b) the permeable and permeable foundation boundary. According to the boundary conditions and related constitutive equations, the dispersion equation of the corresponding Rayleigh wave is deduced and then solved numerically by Newton-Raphson method. Finally, under different boundary conditions, the dispersion characteristics of Rayleigh waves near the surface of unsaturated soil are affected by the saturation and frequency of the soil and the inherent permeability coefficient of soil. The calculation results show that the Rayleigh wave propagation under both boundary conditions is affected by the change of soil saturation. Moreover, the influence of the frequency and the permeability coefficient on the Rayleigh wave properties under different boundary conditions is obviously different.