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针对饱和黏弹性地基中桩基竖向振动问题,基于Boer多孔介质动力控制方程组,在不引入积分变换及势函数的情况下,采用微分算子分解理论并结合桩土接触面的混合边值条件,推导求解相关方程得到了饱和黏弹性地基中端承单桩的桩顶竖向动力阻抗解析表达式.通过和已有相关研究的对比验证了所得解的合理性,并在此基础上进一步通过数值算例对比分析探讨了液固耦合系数、桩长径比、桩土模量比、地基土黏滞阻尼系数对所得桩顶竖向动力阻抗的影响规律.计算分析表明,Boer多孔介质模型和Biot理论的差异不影响饱和土桩体系的共振频率,并且分别基于这两种理论所得到的桩顶竖向动力阻抗在低频阶段是一致的,但在高频阶段,采用Biot理论来描述饱和土的动力学行为将会高估桩土体系的共振幅度.此外,所探讨参数对桩顶动力阻抗均有显著影响.
Aiming at the vertical vibration of pile foundation in saturated viscoelastic soil foundation, based on Boer porous media dynamic governing equations, without introducing integral transform and potential function, the differential operator decomposition theory is used in combination with the mixed boundary of pile-soil contact surface The analytical expressions of the vertical dynamic impedance at the top of a single pile supported on a saturated viscoelastic foundation are deduced by solving the relevant equations.Through the comparison with the existing research, the rationality of the obtained solution is verified and on this basis, The influence of the liquid-solid coupling coefficient, pile aspect ratio, pile-soil modulus ratio and the viscous damping coefficient of foundation soil on the vertical dynamic impedance of the pile top is discussed through numerical examples comparative analysis. The calculation results show that the Boer porous media model And Biot theory do not affect the resonance frequency of saturated soil pile system, and the vertical dynamic impedance of pile top obtained from these two theories respectively is consistent at low frequency stage. However, at high frequency stage, Biot theory is used to describe the saturation The dynamic behavior of soil will overestimate the resonance amplitude of pile-soil system.In addition, the parameters discussed have a significant effect on the dynamic impedance of pile top.