【作者】 周刚；

【导师】 侯建国； 傅少君；

【作者基本信息】 武汉大学 ， 结构工程， 2004， 硕士

【摘要】 土的应力应变问题和固结沉降问题是土工分析中的传统课题，但是鉴于土工问题的复杂性，只有在极少数情况下可以得到问题的解析解。随着计算机和计算科学的发展，目前已有很多数值方法应用于土工领域，其中有限单元法是一种十分有效的土工数值分析方法。本文正是就有限单元法在土工中的应用方面做了一些初步的研究，主要完成了以下工作： (1) 对目前应用较为广泛的一些土工数值分析方法进行了综述，着重介绍了有限单元法的基本原理及其在土工结构分析中的思路，对本文采用的单元形式进行了详细的分析和推导； (2) 介绍了土工结构分析中常用的几种本构模型，说明了它们各自的优缺点及适用范围，重点阐述了本文所采用的几种本构模型的基本理论及推导，并讨论了土工结构非线性问题的求解方法； (3) 对Biot固结理论的基本方程进行了详细的论述，推导了八结点等参单元耦合四结点等参单元的有限元计算公式，并构造了六结点等厚度接触面单元耦合四结点等参单元的新型接触面单元来模拟排水井地基中的涂抹层，使得对采用排水井预压法处理软土地基的模拟更接近于实际； (4) 研究了固结时步自适应误差估计方法，比通常采用的限定时间步长的做法具有更高的精度和更小的计算量； (5) 介绍了本文研制的有限元程序RIFEM的基本结构、主要功能和程序编制过程中的有关技术问题，并对程序进行了考证； (6) 利用本文所研制的有限元程序对杭州湾油罐地基处理工程和深圳宝安区西海堤加高加固工程进行了分析研究，得到了满意的效果，为工程单位进行设计和施工提供了依据。更多还原

【Abstract】 In soil engineering, there are some traditional problems such as stress-strain and consolidation-settlement to be studied. Because of their complexity, only a few problems can get accurate solutions. With the development of computer and numerical modeling techniques, many numerical methods have been established and applied to this field. FEM (Finite Element Method) is one of the most effectives. The application of FEM to soil engineering is studied in this thesis. The main contents are listed as follows:(1) Some widely used numerical methods are summarized. The principles of FEM and the ways of analysis are dissertated in detail. The elements adopted in this study are analyzed and the practical expressions are formulated completely.(2) Some famous constitutive models are introduced. The advantages and disadvantages of these models and their applicable conditions are described generally. Especially, several constitutive models adopted here are also expatiated thoroughly. The nonlinear analysis of soil structure is discussed.(3) The governing equations based on Biot theory are fully expatiated. The method of 8-node iso-parametric element coupled with 4-node iso-parametric element is deduced. And then, 6-node constant thickness contact interface element coupled with 4-node iso-parametric element is developed to simulate the smear layer of drain wells. The new kind of element has made a better simulation of PVD/sand drains-improved ground with surcharge preloading.(4) The error estimation of adaptive time-step in consolidation are studied. Compared with the traditional methods, which usually give limitations to the time step, a better precision and less computation quantity can be obtained.(5) According to the theories and methods mentioned above, the program RIFEM is developed. The basic structure and the main functions of this program are introduced briefly. Some key techniques in programming are also presented. The program has been verified by some examples.(6) Two practical projects are taken as the examples by this program. The results are quite good and can be used in the design and the construction of soil engineering.更多还原