层状饱和土中单桩纵向振动分

基于饱和多孔介质理论，将土体视为液固饱和两相介质，利用Novak薄层法得到了饱和土的竖向动力阻抗，利用传递矩阵法研究了饱和土中桩的纵向振动并进行了参数分析。研究结果表明：桩周土的性质、土层厚度和土层分布对桩顶复刚度有很大的影响，土层剪切模量比越小，复刚度随频率变化曲线的峰值越小，峰值的间隔也越小；对于上软下硬土层，下层硬土层越厚，桩的复刚度随频率变化曲线的峰值越小；土层液固耦合系数的差异对桩的纵向振动特性也存在一定的影响，但相对较小。

Analysis of Vertical Vibration of Single Pile in Layered Saturated Soil

Based on the theory of porous media, the soil was regarded as a two-phase porous medium and the vertical dynamic impedance of soil was formulated using Novak layer method. The vertical vibration of single pile in saturated multi-layered soil was investigated by introducing transfer-matrix approach. The result indicates that (1) The properties of the surrounding soil, the thickness and distribution of soil layers have significant influence on the complex stiffness at the pile head. The peak of the curve of complex stiffness varying with frequency is smaller when the modulus ratio of soil layers is smaller, and the interval between the peaks is also smaller. (2) The peak of the curve of complex stiffness varying with frequency is smaller when the underlying hard soil is thicker. (3) The difference of the liquid-solid coupling coefficient of soil layers has effect on the vertical dynamic properties of the pile in layered soil, but the inffluence is relatively smaller.