考虑桩土耦合作用时弹性支承桩纵向振动特性分析及应用

从三维轴对称角度对弹性支承桩与均质土耦合作用时的纵向振动特性进行了研究分析。假定桩为竖直弹性均匀截面桩,土为线性粘弹性体,其材料阻尼为滞回阻尼,首先通过对土层进行求解得到其振动位移形式解,然后利用该解并以小应变条件下桩土接触界面位移连续来考虑桩土的耦合作用,来分析基桩的动力反应,研究得到了弹性支承桩在谐和荷载作用下频域响应函数解析解,并利用所得解对土层动力反应特性以及桩土体系的振动特性进行了分析,得到了一些新的结论,最后将该理论解与桩顶实测导纳曲线进行了拟合比较,两者较为一致。

SOIL-PILE INTERACTION IN VERTICAL VIBRATIONS OF A PILE WITH ELASTIC BOTTOM BOUNDARIES AND ITS APPLICATIONS

The interaction between a soil layer and a pile with elastic bottom boundaries is investigated theoretically. The pile is assumed to be vertical and elastic and the soil is considered as linear visco-elastic layer with hysteretic type damping. The soil layer is studied first and the vibration displacement solution with undecided constants of soil layer is used in the analysis of pile response. The pile response to a harmonic load is obtained in a closed form and used to define complex stiffness at the level of the pile top. The dimensionless parameters of the problem are identified. Based on the solution, a parametric study is conducted to determine the main features of dynamic reactions of soil layer and the soil -pile interaction in vertical vibrations. It is shown that the theoretical curves are in good agreement with those obtained from field test.