从三维轴对称角度出发,采用粘性阻尼粘弹性连续土介质模型,考虑桩土相互作用效应,对成层土中桩土纵向耦合振动时的桩顶时域响应进行了解析研究。求解时,首先建立定解问题,然后利用拉氏变换先对底部土层进行求解得到其振动位移形式解,然后利用桩土接触界面连续条件来考虑桩土耦合作用,分析底层土中桩段的动力反应,然后利用桩段阻抗函数的传递性,进行逐层递推求解,最终得到桩顶时域和频域响应的半解析解。通过参数影响分析和与工程实测曲线的对比,讨论分析了成层土中桩土耦合振动的响应特性,验证了本文解。基于本文研究可为桩基抗震、防震设计、桩基动力检测提供新的理论支持。
Considering the vertical wave effect on the soil layer, the interaction between the visco-elastic layered soils and a integral pile or a multi-defective pile with arbitrary bottom boundaries and the dynamic response at the pile head to an arbitrary dynamic load is theoretically investigated. And by Laplace transforms and the transmitting property of impedance function, the analytical expression of the impedance function and the solutions of the displacement and velocity response function in frequency domain and in time domain at the pile head are derived. The characteristic of interaction between soil layers is also theoretically investigated here. Finally, to verify the theory developed herein, the fitted curves of analytical solutions are compared with the field measured ones, and it is proved that the theoretical curves are in good agreement with that obtained from the field measurement.