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与实心桩相比,由于土塞与管桩内壁复杂的相互作用,开口管桩的桩-土动力相互作用问题更为复杂。因此,需深入研究考虑土塞效应时的管桩-土体动力相互作用问题。首先,考虑管桩的横向惯性效应及其黏性性质,采用Rayleigh-Love动力杆件模型和附加质量模型建立了桩侧土-管桩-土塞系统的纵向振动控制方程。进一步,采用积分变换和阻抗函数传递技术,分别得到了任意荷载形式下管桩桩顶速度频域响应的解析解以及半正弦脉冲激励作用下桩顶速度时域响应的半解析解。最后,通过与现有解及模型试验的对比研究验证了理论解的合理性,并研究了管桩设计参数对桩顶纵向振动特性的影响。结果表明,当管桩其他设计参数不变时,管桩截面尺寸越大或长度越小时,应力波传播过程中的弥散效应越明显。对于同样外半径的管桩,壁厚越大时,越容易检测到土塞顶部界面及桩尖传来的反射信号,就能对管桩的施工质量进行更为合理的评价。
Compared with the solid pile, the pile-soil dynamic interaction problem of the open pipe pile is more complicated because of the complicated interaction between the soil plug and the inner wall of the pipe pile. Therefore, it is necessary to further study the pipe-soil dynamic interaction problem considering the soil plug effect. First of all, considering the transverse inertia effect and the viscous nature of pipe pile, the longitudinal vibration control equation of pile-soil-pipe pile-soil plug system is established by Rayleigh-Love dynamic member model and additional mass model. Furthermore, the analytical solution of the frequency-domain response of pipe pile top under arbitrary load and the semi-analytical solution of the pile top velocity under the condition of half-sine pulse excitation are obtained by using integral transformation and impedance function transfer technique respectively. Finally, the rationality of the theoretical solution is verified by comparison with the existing solutions and the model tests, and the influence of the design parameters of pile on the longitudinal vibration characteristics of pile top is studied. The results show that when the other design parameters of the pipe pile are unchanged, the larger the pipe section size or the smaller the length, the more obvious the dispersion effect during stress wave propagation. For the same external radius pipe pile, the larger the wall thickness, the easier to detect the reflection signal from the top interface of the soil plug and the pile tip, so that the construction quality of the pipe pile can be evaluated more rationally.