基于多圈层模型的径向非线性饱和土-管桩纵向耦合振动

对径向非线性饱和土-管桩的纵向耦合振动进行了研究。考虑液相的影响将桩周土和桩芯土视为饱和土,同时考虑桩周饱和土沿径向的非线性特性,借助Novak平面假定和多圈层模型将桩周饱和土划分为外部未扰动区域和内部扰动区域,将内部扰动区域又划分为多个同心圆环,建立了基于多圈层模型的径向非线性饱和土-管桩纵向振动的数学模型。利用数学物理手段,并考虑各圈层之间的连续性边界条件得到了径向各圈层纵向剪切刚度的递推公式;在此基础上考虑桩周饱和土和桩芯饱和土对管桩的作用和管桩桩端的边界条件,得到了管桩纵向振动的桩顶复刚度和桩顶导纳。数值算例表明:桩周饱和土沿径向的非线性或非均质特性对饱和土中管桩的纵向振动有影响;液相对管桩纵向振动的影响不应被忽略;管桩外内半径比对管桩纵向振动的影响较大,在设计中需要引起注意。

Longitudinal coupled vibration of radial nonlinear saturated soil-pipe pile based on multi-zone model

The longitudinal coupling vibration of the radial nonlinear saturated soil-pipe pile is studied. The soil around the pile and the pile core soil are regarded as saturated soil by considering the influence of liquid phase, and the nonlinearity of the saturated soil around the pile along the radial direction is also considered. With the help of Novak plane assumption and multi-zone model, the saturated soil around the pile is divided into the external undisturbed area and the internal disturbed area, and the internal disturbed area is divided into a plurality of concentric rings. The mathematical model of vertical coupling vibration of radial nonlinear saturated soil-pipe pile based on multi-zone model is established. Using the method of mathematical physics, the recurrence formulas of shear stiffness of each zone are obtained by considering the continuity boundary conditions, and based on these, the complex stiffness and admittance at pile head are obtained by considering the forces of the saturated soil around the pile and pile core saturated soil on the pipe pile and the boundary conditions at pipe pile tip. The numerical examples show that the nonlinear or non-homogeneous characteristics along the radial direction of the saturated soil around the pile have effect on the vertical vibration of pipe pile in saturated soil, the influence of the liquid phase on the longitudinal vibration of the pipe pile should not be neglected, the ratio of external radius to internal radius of pipe pile have great effect on the longitudinal vibration of the pipe pile, so it need to be noticed in design.