饱和土中单桩复合地基上块体的速度导纳特性分析

根据饱和土弹性波动方程，建立了饱和地基轴对称竖向振动问题的一种有限元-无限元耦合解法并编制了计算程序，其精度应用Lamb问题的理论解来进行检验。参数分析结果表明，地基土的渗透性对单桩复合地基上块体竖向振动速度导纳的低频特性及共振频率影响甚微，但会使高频下的速度导纳幅值有所增大。该方法对饱和土中单桩复合地基动测技术的研究与应用具有一定的理论指导作用。

Analysis of velocity admittance properties of block on saturated composite foundation with single pile

Based on the dynamic governing equations of elastic waves, a hybrid finite-infinite element method is proposed for analyzing axisymmetrically vertical vibration of saturated media. Using the compiled program, the surface vertical displacements of the air-saturated ground (dry soil) are calculated under a surface point excitation, which are agree well with the theoretical solutions of the Lamb’s problem. The velocity admittance curves of block on single-piled composite foundations in saturated soil with varied permeability are calculated with the conclusions that the soil permeability will have few effects on the velocity admittances of block at low frequencies and on the resonant frequency, while the velocity admittances of block at high frequencies will increase with increasing permeability coefficient of soil. The conclusion will be of guide significance on further research of dynamic test method for engineering parameters of composite foundations in saturated soil.