Theoretical and experimental studies are carried out to investigate the characteristics of P-wave and S-wave propagation in soils with different degrees of saturation, which is quantified using Skempton's B-value. Based on the assumption of homogeneous pore fluid and Biot's theory, the characteristics of elastic wave propagation in nearly saturated soils are obtained and the effects of confining pressure, degree of saturation, and excitation frequency on the wave velocities are analyzed. It is found that the evolutions of P-wave, Biot-wave, and S-wave velocities with the degree of saturation are quite different. In experimental bender element tests, the P-wave signal in nearly saturated soil contains two parts. It is inferred that the first part of the P-wave signal is the fast P-wave component and the second part is a Biot-wave (i.e. slow P-wave of the second kind) as their characteristics agree well with theoretical predictions. It is also found that the relationship between the P-wave velocity, V_p, and the B-value depends on the characteristics of the pore fluid. For a pore fluid with de-aired water, the measured V_p is independent of the B-value, which is contrary to theoretical predictions. However, for a pore fluid consisting of tap water (i.e. water with air bubbles), the measured V_p generally increases with the B-value as predicted, and the relationship between the measured V_p and B-value agrees well with the prediction curve when the B-value is smaller than 0.85. When the B-value is larger than 0.85, the measured P-wave velocity is higher than the theoretical prediction, which is probably due to the non-uniform distribution of air bubbles in the pore fluid.

进行了理论和实验研究，以研究不同饱和度的土壤中P波和S波的传播特性，并用Skempton的B进行了量化。-价值。基于均匀孔隙流体的假设和Biot理论，获得了弹性波在近饱和土壤中的传播特性，并分析了围压，饱和度和激发频率对波速的影响。发现P波，Biot波和S波的速度随饱和度的变化是完全不同的。在实验弯曲元件测试中，接近饱和土壤中的P波信号包含两个部分。可以推断，P波信号的第一部分是快速P波分量，第二部分是比奥特波（即第二类慢速P波），因为它们的特性与理论预测非常吻合。还发现P波速度V _p之间的关系，B值取决于孔隙流体的特性。对于具有去水水的孔隙流体，测得的V _p与B值无关，这与理论预测相反。然而，对于由自来水（即带有气泡的水）组成的孔隙流体，测得的V _p通常按预期的B值增加，并且测得的V _p与B值之间的关系与预测曲线非常吻合当B值小于0.85时。当B-值大于0.85，测得的P波速度高于理论预测值，这可能是由于孔隙流体中气泡的分布不均匀所致。