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在频率域内研究了黏弹性土层中端承桩纵向振动的动力特性.将土骨架视为具有分数阶导数本构关系的黏弹性体,基于黏弹性理论,采用平面应变模型给出了分数阶导数黏弹性土层的动力阻抗.考虑桩纵向振动时的横向惯性效应,将桩等效为Rayleigh-Love杆,得到了桩头动力复刚度和导纳的解析表达式.通过数值计算,分析了不同模型土条件下桩头动刚度因子和阻尼随激励频率的动力响应.同时,研究了Rayleigh-Love和Euler-Bernoulli两种模型桩动力特性的差异.分析了桩-土界面连续性模型和相对滑移模型对黏弹性土层中桩纵向振动的影响.结果表明:1随着阶数和材料参数比的增加,桩头刚度因子和阻尼明显减小;2对于大直径桩,随着外荷载激励频率的增加,桩横向效应对刚度因子和阻尼有显著影响.3连续性模型条件下桩头的刚度因子和阻尼在共振时的振幅小于相对滑移模型条件.
In the frequency domain, the dynamic behavior of longitudinal vibration of bearing pile in viscoelastic soil is studied. The soil skeleton is regarded as a viscoelastic body with fractional derivative constitutive relation. Based on the viscoelastic theory and the plane strain model, Derivative dynamic impedance of viscoelastic soil.According to the transverse inertia effect of pile longitudinal vibration, the pile is equivalent to Rayleigh-Love rod, and the analytic expression of dynamic stiffness and admittance of pile head is obtained.By numerical calculation, Dynamic response of pile head dynamic stiffness under different soil conditions and dynamic response of damping with excitation frequency.At the same time, the difference of dynamic characteristics between Rayleigh-Love and Euler-Bernoulli two model piles was studied.Analysis of pile-soil interface continuity model and relative The results show that: 1 With the increase of the order and the material parameter ratio, the stiffness factor and damping of the pile head obviously decrease; 2 for the large diameter pile, with the external load The increase of excitation frequency and pile transverse effect have a significant influence on the stiffness factor and damping.3 The rigidity factor and damping of pile head under resonance are smaller than the relative slip model under the condition of continuous model.