基于多孔介质理论的径向非均质饱和土中管桩的扭转振动

Torsional Vibration of a Single Pipe Pile in Radial Heterogeneous Saturated Soil Based on Theory of Porous Medium

运用多孔介质理论和多圈层法研究了径向非均质饱和土中单个管桩的扭转振动.考虑管桩桩周饱和土的非均质特性,将管桩桩周饱和土划分为扰动区域和未扰动区域,建立了径向非均质饱和土中单个管桩的扭转振动模型.基于Novak薄层法和多圈层法,利用数学物理方法求解了桩芯饱和土和桩周饱和土扰动区域、未扰动区域的扭转振动,并考虑土体边界条件和各圈层间的连续性条件建立了径向各圈层扭转剪切刚度的递推公式.考虑桩周饱和土和桩芯饱和土对管桩的动力作用,建立了管桩的扭转振动方程,得到了管桩桩顶的扭转复刚度.运用数值算例进行了对比分析和讨论.结果表明:研究饱和土中管桩扭转振动时需要考虑桩周饱和土的径向非均质性,高频时不应忽略液相的影响,在进行桩基设计时应重点关注管桩的几何尺寸.

The torsional vibration of a single pipe pile in radial heterogeneous saturated soil was investigated by the theory of porous medium.The saturated soil around the pipe pile was divided into undisturbed area and disturbed area,and the torsional dynamic model of a single pipe pile in radial heterogeneous saturated soil was established.Using the mathematical method,the torsional vibrations of pile core saturated soil,the undisturbed area and disturbed area of saturated soil around the pile were solved by Novak thin layer method and the method of multi-zone,the recurrence formulas of torsional shear stiffness of each zone were obtained by considering the boundary conditions of the soil and the continuity conditions of each zone.The torsional dynamic equation of a single pipe pile in radial heterogeneous saturated soil was established,and also obtained the torsional complex stiffness at pipe pile head.Comparative analysis and discussion were investigated by numeral example,the results indicated that the radial heterogeneous properties of soil around pile need to be considered for studying the torsional vibration of a single pipe pile in saturated soil,and the influence of liquid phase should not be ignored at high frequency,and in the design of pile foundation,the geometric size of pipe pile should be paid close attention to.