非饱和土中Rayleigh波的传播特性分析

Propagation characteristics of Rayleigh waves in unsaturated soils

基于对非饱和多孔介质的研究成果,考虑孔隙中液相和气相的相互影响,研究了非饱和土地基中Rayleigh波的传播特性。通过非饱和土中固相、液相和气相的质量平衡方程、动量平衡方程和非饱和土有效应力原理,建立了问题的弹性波动方程。通过引入势函数及考虑自由透水(透气)的边界条件,经过理论推导给出了非饱和土中Rayleigh波的弥散特征方程。通过数值算例分析了Rayleigh波的波速和衰减系数随饱和度、频率和固有渗透系数等因素的变化规律。结果表明:不同饱和度下波速随频率和固有渗透系数的变化均是先不变,然后小幅下降,再急剧增加,最后趋于一致;衰减系数在不同饱和度下随频率的增大而增大,随固有渗透系数的增大而先增大后减小。

Based on the research of unsaturated porous media,the propagation characteristics of Rayleigh waves in unsaturated soil are studied by considering the interaction between liquid and gas phases in the pores.The elastic wave equations are established using the mass balance equations,the momentum balance equations and the effective stress principle of the unsaturated soil.The dispersion equations of Rayleigh wave in unsaturated soil are derived by introducing potential functions and combining free permeable and breathable boundary conditions.Finally,the effects of saturation degree,frequency,and intrinsic permeability coefficient on the wave velocity and attenuation coefficient are discussed by numerical examples.The results show that the trend of wave velocity is first unchanged with the frequency and inherent permeability coefficient,then decreases slightly,then increases sharply,and finally becomes consistent at different saturations.Moreover,the attenuation coefficient first increases with the increase of frequency and then decreases with the increase of the intrinsic permeability coefficient at different saturations.