改进的薄层单元在桩-土动力相互作用中的应用

发布时间：2018-10-09 09:54

【摘要】：在地震荷载作用过程中,由于桩身材料性能与周围土体性质差异较大,土体在桩-土接触面上发生张开或滑移,该强非线性接触行为直接影响接触面附近土体与桩体应力状态,从而影响上部结构地震响应水平。真实桩-土接触面由于桩身表面混凝土约束关系,具有一定厚度且存在相关体变规律的接触带。通过有限元软件ABAQUS用户自定义单元UEL程序编写改进Desai薄层接触单元,在Desai薄层接触单元中加入Rayleigh阻尼项以模拟地震作用时桩-土强非线性接触行为能量耗散过程。接触面法向与两切向本构关系采用双曲线模型。规定了Desai薄层接触单元在桩-土接触面上的行为模式以模拟土体在接触面黏结、滑动、张开、再闭合等接触状态。建立精细三维桩-土-结构体系动力相互作用模型以研究改进Desai单元对上部结构峰值动力响应水平影响,为工程结构抗震设计时程分析提供参考依据。
[Abstract]:In the course of seismic loading, the behavior of pile material is different from that of surrounding soil mass, and the soil is open or slippage on the pile-soil interface. The strong nonlinear contact behavior directly affects the stress state of soil and pile near the contact surface. Therefore, the seismic response level of superstructure is affected. Due to the concrete constraint on the surface of the pile, the real pile-soil contact surface has a certain thickness and there is a contact zone with the related body variation law. The improved Desai thin layer contact element is programmed by the UEL program of the user defined unit of finite element software ABAQUS, and the Rayleigh damping term is added to the Desai thin layer contact element to simulate the energy dissipation process of the strong nonlinear pile-soil contact behavior under seismic action. The normal and tangential constitutive relations of contact surfaces are hyperbolic. The behavior model of Desai thin layer contact element on the pile-soil interface is defined to simulate the contact state of soil in the interface such as bonding sliding opening and closing. A fine three-dimensional pile-soil-structure system dynamic interaction model is established to study the effect of improved Desai element on the peak dynamic response of superstructure, which provides a reference for seismic design time history analysis of engineering structures.
【作者单位】：华中科技大学土木工程与力学学院;
【基金】：国家自然科学基金项目(No.51378234) 华中科技大学优青培育基金项目(No.2014YQ008)~~
【分类号】：TU435

【参考文献】