FEM Of Geotechnical Structures

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...