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为了探讨考虑剪切变形的PCC桩水平振动特性,首先,采用Timoshenko模型模拟PCC桩,建立其水平振动控制方程;其次,采用微分变换和分离变量法对三维土体控制方程进行解耦,推导出土体位移和水平阻抗解析表达式;然后,结合桩土连续性条件,推导出PCC桩动力复阻抗解析表达式。由此进行算例分析表明:Timoshenko模型与Euler-Bernoulli模型推导的桩顶水平动力复阻抗变化规律一致,验证了解的合理性;复阻抗实部均随桩长增加而减小,虚部均随桩长增加而增大,当桩长增加到临界桩长时,桩长对复阻抗实部和虚部基本没有影响;复阻抗随内径减小而增大,当内径减小至0.2 m及以下时,桩芯土对复阻抗影响不大;当横截面面积相同时,平均半径和壁厚对复阻抗均有显著影响。
In order to investigate the horizontal vibration characteristics of PCC piles considering shear deformation, first, the Timoshenko model was used to simulate PCC piles to establish the horizontal vibration control equations. Secondly, the governing equations of three-dimensional soil were solved by differential transformation and separation variables method, Body displacement and horizontal impedance analytic expression; Then, combined with the conditions of pile-soil continuity, the analytic expression of dynamic complex impedance of PCC pile is deduced. The results show that the Timoshenko model is consistent with the Euler-Bernoulli model to derive the change rule of horizontal dynamic complex impedance at pile top, and the rationality of the solution is verified. The real part of complex impedance decreases with the increase of pile length, When the pile length increases to the critical length, the pile length has no effect on the real part and the imaginary part of the complex impedance. The complex impedance increases with the decrease of the internal diameter. When the internal diameter is reduced to 0.2 m and below , The pile core soil has little effect on the complex impedance; when the cross-sectional area is the same, the average radius and wall thickness have a significant effect on the complex impedance.