The linear approximation method is frequently adopted in the calculation of dam seepage fields. For the rockfill structures

however

the relationship between hydraulic gradient and bulk velocity deviates from the linearity at higher hydraulic gradients due to the presence of combined inertial and turbulence effects; and the complex interface between different porous media in the seepage fields is another issue that adds to the complexity of flow through most rockfill structures. Therefore

it needs to improve precision and objectivity for the description of the seepage behaviors by the application of non-Darcy flow theory. A nonlinear finite element formulation based on Forchheimer equation is established by using the method of Galerkin weighted residuals; and the numerical simulations of seepage flow in rockfill dam are developed by using the method. The study shows the numerical simulation model based on non-Darcy flow equation can be an effective approach to the research on non-Darcy flow behavior. With the comparison of the two solutions by using Darcy method and non-Darcy method

significance of non-Darcy flow analysis method in such projects has been indicated. As to rockfill dam

calculation results by non-Darcy method show that the diffusion of high hydraulic gradient can appear in the local region of the seepage field; and the results also show that maximum value of hydraulic gradient somewhat increased compared with that in the linear calculation method. It means maximum value of hydraulic gradient can exceed the critical value in real seepage field; and it may possibly cause the seepage failure of the dam.