桩与粘性阻尼土耦合扭转振动时域响应研究

Time domain torsional response of dynamically loaded pile in viscous damping soil layer

假设桩周土层为均质粘弹性体,土材料阻尼为粘性阻尼,从轴对称角度出发,对任意激振扭矩作用下弹性支承桩与土耦合扭转振动时的桩顶时域响应进行了理论研究,求得桩顶扭转角阻抗函数解析解,给出半正弦脉冲激振扭矩作用下桩顶速度时域响应半解析解。基于所得解对桩土系统的扭转振动特性进行了分析,讨论了桩土耦合扭转振动条件下长径比、波速比、桩底支承条件等因素对桩顶时域响应的影响,探讨了桩侧土粘性阻尼的特殊影响,得到若干新的结论。

Assuming that the soil is uniform linear viscouselastic layer with viscous damping,the time domain torsional response of dynamically loaded pile in the soil layer is theoretically investigated. And the corresponding solution of the displacement and velocity response function at the pile top end in frequency domain is obtained in a closed form. Then,by means of invert Fourier transform, a quasi analytical solution of velocity response of the pile in time domain subjected to a half sine wave excitation force is obtained. Based on the solution,a parametric study is conducted to determine the main features of the soilpile interaction, and the special influences of viscous damping of soil layer are also discussed.