Hydraulic structures should be secured against uplift pressure and piping. Design engineers, therefore, may provide these structures with different features such as intermediate filters to establish safer and/or more economic structures. One or more intermediate filters can be built within the floor. In this research, the problem of seepage flow beneath hydraulic structures with two plane intermediate filters over a homogenous soil has been deduced analytically using the conformal mapping technique. The solutions include the potential heads at both key and stagnation points, the hydraulic exit gradient just downstream the floor, and the location of the stagnation points. The results have been used to create design charts over a wide range of variables. Then, the general steady-state seepage problem beneath a floor of hydraulic structure having any shape provided with any number of filters and cut-offs located anywhere over a heterogeneous soil has been obtained using a finite element model. After calibrating the model, it has been applied to solve the same problem studied analytically using conformal mapping to confirm both solutions and to determine the adequacy of the numerical solution for potential heads, exit gradient and location of the stagnation points. Good agreement between both solutions has been obtained confirming the accuracy of the numerical solution. Then the model has been used to check the stability against uplift and piping for New Esna Barrage on Nile River in Egypt as one of the existing barrage, which has been provided with one intermediate filter. After the stability of the barrage against these forces has been confirmed, many alternative designs for its floor have been studied to investigate where the exist solution from the optimum one. These alternative designs include different lengths and location for the filter and an upstream cut-off with different depths. Finally the finite element model has been applied over a wide range of variables for a comparison study between the effect of using one and two plane filters upon uplift pressures, hydraulic exit gradients and seepage discharges
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:510438 |
| Date | January 2000 |
| Creators | Farouk, Mohamed Ismail |
| Publisher | University of Manchester |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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