低承台管桩纵向自由振动特性分析

Vertical free vibration features of a pipe pile with low cushion cap

基于广义Voigt模型和附加质量模型,研究了低承台管桩的纵向自由振动特性。首先,根据承台和管桩周围土体的性质,建立了承台、管桩、桩侧土以及土塞纵向自由振动的控制方程;然后,结合承台-管桩-土系统的耦合条件,采用Laplace变换技术及阻抗函数传递法,求解得到了承台纵向自由振动位移的频域解析解及时域半解析解。最后,分析了附加质量模型中Voigt模型参数的敏感性区间,并将该解退化与已有解进行对比,验证了该解的合理性;讨论了桩身参数、土塞、桩侧土及承台周围土体对低承台管桩纵向自由振动特性的影响规律。结果表明:桩身参数、土塞、桩侧土及承台周围土体对低承台管桩纵向自由振动特性有明显影响,为低承台管桩基础的防震减震设计提供了一定的理论依据。

Based on the generalized Voigt model and additional mass model,vertical free vibration features of a pipe pile with low cushion cap was investigated.Firstly,according to properties of soil surrounding pipe pile and cushion cap,vertical free vibration governing equations of cushion cap,pipe pile,soil surrounding pipe pile and soil plug were established.Then,considering coupling conditions of cushion cap-pipe pile-soil system,using Laplace transformation technique and the impedance function transfer method,the frequency domain analytical solutionand the time domain semi-analytical solution tothe vertical free vibration displacement of cushion cap were obtained.Finally,sensitivity intervals for parameters of Voigt model in the additional mass model were analyzed,and the rationality of the obtained solutions was verified through comparing degradations of these solutions with the existing solutions.Effect laws of pipe pile’s parameters,soil plug,soil surrounding pipe pile and soil surrounding cushion cap on vertical free vibration features of the low cushion cap-pipe pile-soil system were investigated.The results showed that parameters of pipe pile,soil plug,soil surrounding pipe pile and soil surrounding cushion cap have significant effects on vertical free vibration features of the pipe pile with low cushion cap to provide a certain theoretical basis for seismic design of pipe piles with low cushion cap.