桩土动力分析中二维接触模型的研究

根据桩土动力相互作用中的接触界面特性,提出了考虑桩土分离、滑移以及桩基提离效应的二维接触模型的本构行为,推导了其相应的单元刚度矩阵,同时引入阻尼成分考虑了桩土动力相互作用中部分能量的耗散问题,并研究了二维接触单元的厚度选择。通过算例分析,得出在中小地震作用下应用接触模型计算得到的上部结构的加速度反应、水平位移反应都较Goodman接触单元有不同程度的降低,且强震作用下的接触模型反映出了桩土动力相互作用中的桩土分离、滑移以及桩基提离效应。

RESEARCH ON PLANAR CONTACT MODEL OF DYNAMIC SOIL-PILE INTERACTION

According to the character of the interface between soil and pile in the dynamic soil-pile interaction, the constitutive relationship of a new planar contact model considering the effect of separating, sliding and pile uplifting is presented, and associated element stiffness matrix of interface element is deduced. Then the problem describing the energy dissipation of interface element during dynamic interaction is solved by adding the damping component, and method of determining the thickness of interface element is proposed. Compared with the Goodman element, the seismic response (acceleration, displacement) of superstructure obtained by use of the planar contact model under moderate earthquake is reduced. Thusly, the planar contact model can simulate the effect of separating, sliding and pile uplifting in the dynamic soil-pile interaction under strong earthquake.