Study Of Key Problem On Numerical Method Of Three-dimensional Unsteady Seepage With Phreatic Surface

The mechanism of fluid flow in the media must be studied in the fields of hydraulic engineering geotechnology engineerings hydrological geology engineering oil industry chemical industry environmental protection coastal engineering and so on, For example, the effect of the dam's stability is studied during the hydraulic engineering, when the water level falls in the reservoir; and the flux is considered during the foundation excavation The fluid flow is a complicated three-dimensional problem, and time effect is often considered A deep research aiming to this problem has been done and the following contents are studied in details:1. The devolopment status chiefly existent problems the usual research and numerical method are introduced briefly during the analysis of the unsteady seepage, and the equation of the three-dimensional unsteady seepage is deduced by the theory of the three-dimensional consolidation;2. The finite element equation is deduced firstly with eight nodes, and the corresponging programme is compiled All kinds of boundary conditions are discussed in the programme involving the phreatic surface etc, especially the calculating of the integral item which can calculate the position of the phreatic surface accurately is discussed;3. A deep research is done on the phreatic surface of seepage through the method of variational inequality, the approximate expressions the finite element equation and so on are discussed, and the corresponding programme is compiled;4. During the analysis of the seepage, the frozen points show the intensive irregularity, the usual method cann't solve this problem well, so a deep research is done on the basis of the predecessor, and the corresponding programme is compiled;5. A deep research is done on the difference method, and a kind of method with high precision and quick convergence is discussed in details The convergence of the unsteady seepage calculation can be improved remarkable with this method;6. In order to varity the programe, a great deal of examples involving the experiments and the engineering problem are calculated, and the effect of the volumetric water content of the permeating medium and the size of the elements are discussed in details...