Pile-top impedance of pile foundation in liquefied soil based on viscous fluid mechanics
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摘要: 将液化后的土体视为流体，考虑液化土的黏性，研究了黏性液化土体中端承桩的水平振动问题。用黏性流体运动方程模拟液化后土层的运动，用饱和多孔介质模型模拟饱和未液化土层，联系桩-流体耦合条件运用势函数法、分离变量法得到黏性流体水平振动解析解。利用上层液化土和下层饱和非液化土分界面的位移、转角和内力连续条件得到黏性液化土-饱和土分层条件下的桩顶阻抗解析表达式，将理论解与有限元解进行对比验证了解的正确性，对端承桩桩顶阻抗进行参数分析，表明在分析液化土中桩基桩顶阻抗时，需要考虑液化土的黏滞特性，以免造成刚度阻抗的高估和阻尼阻抗的低估。Abstract: Regarding liquefied soil as the fluid and considering its viscosity, the horizontal vibration of the end-bearing pile in viscous liquefied soil is studied. The motion of the liquefied soil layer is simulated by using the viscous fluid motion equation, and the saturated soil layer is simulated by the saturated porous medium model. The analytical solution for the horizontal vibration of viscous fluid is obtained by separating the variables according to the pile-fluid coupling condition. Based on the continuous conditions of displacement, rotation angle and internal force of the interface between the upper liquefied soil and the lower non-liquefied saturated soil, the expression for pile-top impedance under the layered condition of viscous-liquefied-soil saturated soil is obtained. Compared with the FEM results, the correctness of the analysis is verified. A parametric analysis of the pile-top impedance shows that the viscous characteristics of the liquefied soil should be considered when analyzing the impedance of pile foundation in the liquefied soil so as to avoid the overestimation of stiffness impedance and the underestimation of damping impedance.
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Keywords:
- liquefied soil /
- viscosity /
- fluid /
- pile foundation /
- horizontal vibration
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图 1 桩基水平振动计算简图
Figure 1. Simplified calculation graph of horizontal vibration of foundation
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