Theoretical Solution for Seepage Flow in Overtopped Rockfill

Abstract

Non-Darcy flow conditions can develop for flow over a rockfill dam with a wide profile (e.g., a high rockfill dam under construction in a flood period), flow in gravel river reaches, and overland flow. Non-Darcy flow can also occur in nonconventional rockfill spillways. Such conditions are due to seepage flow with a high Reynolds number in rockfill (or gravel) and the interaction between the overtopping flow and the seepage flow. In this paper, theoretical solutions for the turbulent seepage flow at the transition zone (that is, the seepage zone between the overtopping zone and the pressure seepage zone) are presented. The Prandtl mixing-length turbulent theory is used with the non-Darcy seepage law to solve the problem. Analytical results are compared with published experimental data.