【作者】 阮光雄；

【导师】 陈胜宏； 傅少君；

【作者基本信息】 武汉大学 ， 水工结构工程， 2004， 博士

【摘要】 关于提高有限元法解的精度和稳定性问题受到不少学者的重视。 本文以Biot固结理论为基础,研究了固结过程中的时步自适应问题。用基本原理推导出时步控制公式,从而全面控制应力和孔隙压力场。研究结果有助于准确模拟应力应变的发展,对粘土心墙土石坝等建筑物的设计及施工有重要意义。 土石坝工程运行时经常受到地震的动力作用。本文以Blot动力固结理论为基础,应用改进的数值解法来求解动力方程。并且通过液化判断标准来估计土石坝的动力稳定性。 本文还结合作者的一些认识,介绍目前动力分析的研究状态和最新的进展,对相关问题的研究提出一些看法。 本文主要内容有: (1) 采用Biot固结理论,建立了时步自适应方式。 (2) 研究了土体的动力性质。 (3) 研究了土石坝动力分析方法,应用改进数值Hilber-Hughes-Taylor-a来求解动力方程。 (4) 讨论了液化现象和液化发生过程,并从提出液化发生的条件。 (5) 用Fortran语言开发了应用程序。 (6) 应用上面建立的理论与研究分析了越南的Dakyen土石坝。更多还原

【Abstract】 The accuracy and stabilility of a problem solved by FE method is concerned and taken in to account by many researchers.In this thesis, the adaptive time step is used in FEM for analysing consolidation problems and dynamic problems. The key points discussed in detail are listed as follows:In order to improve the numerical accuracy and stabilility, based on Biot’s consolidation theory the adaptive time step algorithm is introduced. The method is to estimate local and global errors of stress state and pore pressure. By the link between errors and time step length the time step adaptivity strategy has been proposed.This study can provide well understanding of development of the relation between stress and strain by time. Furthermore the study will be very useful for the design and construction of dams with earth core wall. Earth dam is usually subject to earthquake action. Based on Biot’s consolidation theory the dynamic analysis technique is introduced for solving dynamic consolidation problems, then the liquefaction criteria is used to estimate the seismic stability. The study will be very useful for the design and construction of earth dam.Beside all the works listed above, base on the author’s knowledge, the state of the art and the recent development in dynamic FEM analysis are discussed systematically. Some reviews on the topic will be given, It is desired that this work should contribute to researchers in keeping abreast of the new developements and trends in dynamic FEM problems. The thesis is organized as follows:First, the FEM on soil consolidation problems is introduced .From the result of study, the adaptive time step algorithm is presented.Secondly, discuss on dynamic analysis problem is conducted , theattention is paid to the earthquake .Thirdly, dynamic analysis method on local material dam is dicussed and Hilber-Hughes-Taylor-a method is applied for solving dynamic equation.Fourthly, discuss on the liquefaction is presented.Fifthly, based on Fortran languge the computation program is developed for solving consolidation problems and dynamic problem in geotechnical structures.Finally, Dakyen’s local material dam is studied using the above theory and program更多还原