Spatially varied flow over rockfill embankments

Abstract

A procedure for determining the flow conditions through and over a simple, rockfill embankment having a horizontal top surface is presented. In this situation, the free surface flow regime can be characterized as spatially varied and the seepage flow regime as non-Darcian. Included in the paper are a review of spatially varied flow theory and analysis, a brief description of the numerical method used to conduct the non-Darcy seepage analysis, a few comments with respect to the determination of the flow properties of the model rockfill, and a discussion of the application of the analysis procedure to a model rockfill embankment. Two flow conditions were tested. The one flow condition was for partial overtopping of the embankment, while the other involved complete overtopping. The spatially varied flow analysis was carried out using a spreadsheet, and it included the incorportion of Hinds' method for control point location. A modified version of a Darcian finite element seepage program was used for the seepage analysis. The computed results are compared with those obtained from a physical model. As shown in the paper, the results are generally supportive of the proposed modeling procedure. Key words: control point, non-Darcy seepage, numerical model, physical model, porous media, rockfill, spatially varied flow.