非饱和土中剪切S波的传播特性分析

Propagation Characteristics of S-waves in Unsaturated Soil

摘要:

基于对非饱和多孔介质的研究成果，考虑孔隙中的液相和气相的相互影响，研究非饱和土地基中剪切S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，建立问题的弹性波动方程，经过理论推导给出非饱和土中剪切S波的弥散特征方程。通过数值算例分析剪切S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，剪切S波的波速几乎不受饱和度的影响，但其随着频率的增大而减小，随着固有渗透系数的增大先不变后增大；剪切S波的衰减系数随着饱和度和频率的增加均增大，而随着固有渗透系数的增大先不变后增大最后减小。

Abstract:

Based on research into unsaturated porous media, propagation characteristics of S-waves in unsaturated soil were studied by considering the interaction between liquid and gas phases in the pores. Elastic wave equations were established according to the mass balance equation, the momentum balance equation, and the effective stress principle of unsaturated soil. The dispersion equation of S-waves in unsaturated soil was obtained after theoretical deduction. Finally, the influences of saturation degree, frequency, and intrinsic permeability coefficient on S-wave velocity and attenuation coefficient are discussed using numerical examples. Results showed that the wave velocity of S-waves is hardly affected by degree of saturation, but decreases with increasing frequency; it first remains unchanged, then increases with an increasing intrinsic permeability coefficient The attenuation coefficient of S-waves increases with increasing saturation degree and frequency; however, with increasing intrinsic permeability coefficient, it first remains unchanged, then increases, then finally decreases.