地震激励下桩-土非线性耦合作用对桩基动力响应特性的影响

为探讨桩-土非线性耦合作用对桩基动力响应特性的影响,以桩-土-结构耦合系统为研究对象,建立三维非线性有限元模型。采用Drucker-Prager非线性土体本构模型,利用罚函数法实现桩-土-结构界面间的非线性耦合作用,引入无反射边界条件,并考虑重力因素,得到了水平和竖直方向组合地震激励下桩-土非线性相互作用对桩基地震响应的影响。结果表明,考虑桩-土接触非线性,桩基的加速度响应峰值减小,桩土之间出现明显的分离现象,桩基剪力和弯矩峰值有所增加。通过对桩基轴力的校核,桩基不承受拉力,不会发生拔桩现象。

Effects of pile-soil nonlinear coupling actions on dynamic response features of pile foundation under earthquake

The dynamic response features of pile foundations with soil-pile nonlinear coupling actions were investigated by conducting nonlinear 3D finite element numerical simulations. The soil-pile nonlinear coupling actions, such as, non-reflecting boundary condition and soil-pile dynamic interaction were modeled with the penalty function method. The simulation results showed that considering the nonlinearity of soil-pile contact, the peak acceleration of pile foundation decreases; the obvious phenomenon of separation between soil and piles appears; the shear force and bending moment increase due to soil-pile nonlinear interaction; there is no axial tensile force in piles.