非均质土中基于虚土桩法的桩基纵向振动

Vertical vibration of pile based on fictitious soil-pile model in inhomogeneous soil

在考虑桩底有限土层影响的情况下,研究非均质土中桩在纵向振动荷载作用下的动力特性.在将桩截面积范围内有限层桩底土模拟为虚土桩的基础上,建立虚土桩-土、桩-土耦合振动模型,采用复刚度传递多圈层平面应变模型建立桩、虚土桩与桩侧土的纵向振动动力方程,利用桩-土、虚土桩-土以及虚土桩-桩的耦合接触条件求解动力方程,得到桩顶频域响应解析解和时域响应半解析解.通过对虚土桩参数的研究检验桩底土对桩动力响应的影响,得到一系列桩顶速度导纳曲线、时域反射波曲线以及复刚度曲线表现规律图.

The dynamic response of pile in inhomogeneous soil was analyzed under vertical dynamic loads by considering the influence of finite soil layers under pile. The dynamic interaction model was conducted based on the finite soil layers of which the cross-section area is equal to the pile were modelled as fictitious soil-pile. The dynamic equations of fictitious soil-pile, pile and soil were built by complex stiffness transfer model of radial multi-zone plane strain and solved by using the continuity condition of fictitious soil-pile, pile and soil. Then the analytical dynamic response solution in frequency domain and the semi-analytical dynamic response solution in time domain at the top of pile were obtained. Parametric studies of fictitious soil-pile were performed to examine the effect on the dynamic responses of pile. The curves of the velocity admittance, reflected wave and complex stiffness at the top of pile were obtained.