Hydraulic Analysis of Overtopping Flow on Rockfill Gabion Constructed along Soil Embankment Slope of Farm Pond

<p>Hydraulic analysis of overtopping flow on rockfill gabion constructed along soil embankment slope of farm pond was developed, and its numerical accuracy was investigated by comparing with overtopping tests in laboratory water flume inclined 20 and 30 degrees of slope. During flood overtopping on the rockfill gabion, there appear both a flow seeping through the rockfill gabion and a flow running over the rockfill. Hydraulic behavior should be properly determined to design a mechanically stable rockfill structure during flood overtopping. A nonlinear FEM seepage analysis and a numerical integration method of the spatially varied flow equation along a large slope of flow were formulated to compute the hydraulics of flows through and over the rockfill gabion, respectively, then combined in an iterative solution technique to solve an exchange of flow mass through the top surface of the rockfill. The hydraulic analysis provides good comparisons of water profile and discharge velocity with those measured in the overtopping tests of the rockfill gabion packed with round cobbles 100 to 200 mm in diameter. A successive improvement of the combined hydraulic analysis is required so that the hydraulics of overtopping flow on the gabion mattresses, which may be the most promising overtopping protection for a farm pond embankment dam, will be properly evaluated.</p>