Author(s): Ahmed M. Abdelrazek; Mohammad A. Abourohiem
Keywords: Gravity hydraulics structures; Confined seepage; Unconfined seepage; Free surface; Design charts
Abstract: Existence of a drop in a stream bed may create a confined seepage followed by an unconfined seepage simulta neously occur in the same field under gravity structures, whic h is called a combined seepage. The current paper is inte nded to develop an a nalytical solution fo r the problem of combined seepage below gravity hydraulics structures based on pervious layer with a dropped surface. The developed solution can define the ma ximum height of the free surface and in turn the seepage discharge as well as the location of the free surface once the main parameters are fixed. These parameters are; length of the floor, depth and location of the sheet pile, depth of the foundation layer, horizontal distance between the structure and the drop, head and tail water depths, le ngth of the unconf ined zones, drop and height slope. The effect of these parameters, on the seepage discharge and the location of the free surface, is analyzed. The results are formed in the shape of dime nsionless design charts. Using such charts, the ma ximum height of the free surface and the seepage discharge are easily found.