桩土耦合扭转振动理论研究与特性分析

Study on soil-pile interaction in torsional vibrations

从三维轴对称角度出发,对弹性支承桩与均质土耦合作用时的扭转振动特性进行了研究分析。假定桩为竖直弹性均匀截面桩,土为线性黏弹性体,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扭转角的形式解,然后利用该解并以小应变条件下桩土接触界面位移连续和力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激振扭矩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扭转振动特性进行了深入分析,得到了一些新的结论。

The interaction between soil layer and a pile with elastic bottom boundaries was investigated theoretically. The pile was assumed to be vertical and elastic, and the soil was considered as linear visco-elastic layer with hysteretic damping. The soil layer was studied at first and the vibration displacement solution with undecided constants of soil layer was used in the analysis of pile response. The pile response to a harmonic torque was obtained in a closed form and used to define complex stiffness at the level of the pile top. The dimensionless parameters of the problem were identified. Based on the solution, a parametric study was conducted to determine the main features of dynamic reactions of soil layer and the soil-pile interaction in vertical vibrations.