The Finite Element Method For Seepage Using Biot Consolidation Equation As Control Equation

In hydraulic and hydropower engineering, the seepage calculation is a routine subject often confronted and applied in wide range. In porous medium, the F.E.M. for steady seepage is mature little by little, no matter in the field of choice of control equation, or of application of F.E.M..However, the unsteady seepage calculation is various in establishing mathematic model for its control equation is also various. Moreover, there are difficulties in application of F.E.M..Based on deep analysis of unsteady seepage's physical process in the porous medium, mathematic model has been established with Biot consolidation equation as the control equation, which could most reflect the seepage. In the application of F.E.M., fixed mesh method is adopted because of the self-goodness, but there are some discrepancies in the blending process of Bathe Method and the unsteady seepage's control equations. First, the basic principle of seepage and methods used in seepage analysis has been described briefly, and then their merits and their demerits are compared. In F.E.M. for seepage calculation, beginning from the condensable flow in the deformable and aeolotropism medium, which is in the complex stress, various simplified control equations have been deduced, and then their physical model, basic assumption, application condition and mutual relation are explained systemically. Second, several methods common in use are introduced, including A.M.M., Residual Schemes Method, Bathe Method and Initial Flow Method. On the base of this, it is put forward that the discrepancies between some mathematic models using in unsteady seepage analysis and them. Owing to several F.M.M. based on the steady seepage, it is inevitable that there are discrepancies when they are applied to the unsteady-state directly. Biot consolidation equation is more mature coupling fluid and solid theory applied in porous medium. Since it was established in 1941, it has not been applied to engineering because of calculation's difficulties. With the development of the F.E.M., Biot consolidation is just began to apply to. In the end, the program ME1SEEP for coupling fluid and solid analysis has been coded in C++ language, which uses Biot consolidation equation as control equation. And the planning and developing processes of software ME1SEEP are described. After analyzing seepage in the dam base, the results demonstrate that it is feasible.