Analysis Of Steady Seepage And Unsteady Seepage In Unsteady Earth Rock-fill Dam Based On Finite Element Method

With the popularity of the computer technique, numerical calculation method is becoming more and more important in solving complex practical problems, which is applied in various fields. In the field of seepage calculation, the finite element method has been attached high importance for its big and powerful adaptability to complicated boundary anisotropic and three dimensional seepage. Today, there are many problems about seepage in hydraulic and electric engineerings. Because of many virtues such as low cost, simple structure, good adaptability, good capacity of resisting earthquake and long life, earth rock-fill dams are adopted abroadly. For earth rock-fill dams, problems about seepage are very serious, it is necessary to analyze seepage in earth rock-fill dams feasibly and correctly.In this thesis, seepage analysis model is built, and corresponding calculation programs are compiled. Finite element theory and calculation about steady seepage and unsteady seepage in earth rock-fill dam are researched systemically on the basis of former research achievments. The following is included:(1) Available research achievements about seepage are collected. Based on basic theories of seepage and finite element, several prevailing methods used to solve free surface in unconfined seepage have been appraised. In this thesis, the initial flow method of fixed mesh methods is used to calculate steady seepage, and there are some modifications for seepage program, This program has been validated to be feasible and accurate by example. Furthermore, seepage analysis has been done for Wuhan dike.(2 ) The methods of calculating free surface for steady seepage and calculating correlative factors including seepage scope, velocity of seepage and so on are analyzed. Program in Fortran is compiled to build plot files in AutoCAD, and by them some figures are protracted automatically.(3) Based on finite element theory, analysis program about unsteady seepage under the variable water-level is finished, and several problems have been showed during compiling program. This program has been validated to be feasible and accurate by example. Seepage analysis are done for Yunxi earth rock-fill dam and Shanbanxi falling coast in Hunan, at the same time, stabilization of dam scope is discussed simply under the variable water-level.(4) Based on finite element method, free-line change orderliness with seepage parameter variety has been analyzed when water-level in reservoir falls, internal relation between seepage parameter and average comparative error from free-lines is built, some predigestion analysis on finding free-line location of unsteady-seepage in homogeneous earth-dam when water-level in reservoir falls. And some valuable conclusions have been made.Finally, in this thesis finite element method about seepage is evaluated synthetically, and the further development in this field is forecasted, including: 3-D saturated-unsaturated seepage, simulation and calculation of drainage hole, stable analysis for dam slope under the variable water-level, effect on freeline in dam from the variable water-level and scope angle and so on.