文档介绍：南华大学
硕士学位论文
基于ABAQUS的深基坑变形三维有限元分析
姓名:甄精莲
申请学位级别:硕士
专业:结构工程
指导教师:段仲沅
20070501
摘要
本文论述了深基坑工程和支护结构变形有限元法的发展现状,分析了目前基坑工
程中频繁出现事故的原因,根据基坑工程特点,强调了动态设计的重要性,避免仅依
赖于理论计算进行设计与施工。
本文采用 ABAQUS 有限元软件模拟基坑的施工过程,根据基坑土体的物理力学
性质,选择了德洛克-普拉格(Drucker-Prager)屈服准则。该准则假定土体是理想
的弹塑性体,能够较好的模拟基坑开挖过程中土体的应力应变状态。通过选择合适的
计算范围,建立相应的模型。土体单元及人工挖孔桩采用三维八节点实体减缩积分单
元(C3D8R)模拟。并对模型进行网格划分,分别定义土体和结构单元的材料性质,采
用位移边界条件定义基坑的边界及施加约束。通过对模型加载模拟基坑施工过程,对
基坑工程在施工过程中的变形进行三维弹塑性有限元分析。分析过程中采用非线性问
题中的第三类非线性问题,即边界条件的非线性问题,数值计算基于 ABAQUS 采用
罚函数方法求解结构面的接触问题,考虑了桩、土两种材料接触面受力的影响;对基
坑工程施工不同工况下支护结构的变形进行模拟,将其模拟结果与基坑工程施工实际
监测数据进行对比分析,通过调整有关参数反复进行模拟,最终找出合理的模型。本
文通过对工程实例施工过程的模拟,验证模型的合理性。通过对基坑工程施工各工况
模拟预测基坑的变形,并提出相应的施工措施,用以指导工程实践。
关键词:三维弹塑性;有限元;接触面;基坑变形;预测
I
Abstract
In this paper, the developing condition of deep foundation pit and deformation of
supporting structure, the reason of works accident at present are described, and the
importance of the dynamic design according to the engineering feature is emphasized , so
we can’t only depend on the predict value in the actuality.
The foundation pit excavation is simulated by the software ABAQUS ,
Drucker-Prager model is choosed in the paper, which is perfect elastoplastic body to
simulate stress-strain relations of soils. Through choosing appropriate calculation scope
builds relevant Models. C3D8R is adopted to simulate for Soils element and manual
excavation pile. Mesh partitioning and load for the model, material type for the soils and
construction element, boundary condition for the foundation pit are discussed. The
deformation of foundation pit excavation is analysised for the three dimensional elastic and
plastic finite element. Analysis procedure is described by nonlinear problem with boundary
condition. Numerical calculation is based on ABAQUS which adopts penalty function to
solve the structural plane contact problem. The deformation of foundation pit excavation
for differ