The Analysis And Application Of 3-D Unsteady Saturated-Unsaturated Seepage FEM

The author has particularly researched into the prominent problems of seepage in water conservancy engineering based on the steady-unsteady and saturated-unsaturated seepage theory and numerical method by summarizing the former achievement. The following is included:(1) Based on the fundamental seepage theory, the basic differential equation of saturated-unsaturated seepage in porous mediums has been deduced, in which the pressure head is the fundamental unknown quantity. The method for saturated-unsaturated possible spill boundary handling is presented. Particularly, two formulae are established for the problem of unsaturated spill boundary. The 3D saturated-unsaturated FEM program is developed by which changes processes of seepage fields with changes of water level in a certain section of Nanjing dike have been analyzed.(2) Based on the saturated-unsaturated seepage theory, the mathematic model under the condition of rain infiltration has been deduced. The problem of mathematic model is primarily solved and the rain infiltration boundaries have been successfully handled. Additionally, the typical rain processes and the influence of rain infiltration in a certain diggings are impersonally simulated.(3) Based on the method of nodal virtual flow rate of an unvaried finite mesh, the theoretic arithmetic for improving drainage substructure and the handling method of hole boundary conditions are discussed in order to solve the problem of drainage holes simulation.Furthermore, the aperture element model without thickness is present on the basis of the character of RCC dams and the symmetrical and anisotropic equivalental sequential model .The complicated seepage control measures of Jiangkou dam foundation. The result indicates that improving drainage structure may successfully deal with the problem of the simulation qf dense drainage holes and the problem of seepage model of RCC dams are fundamentally solved .