الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Failure in earth dams mainly occurs due to seepage to the unprotected downstream face of the dam. Therefore, Seepage through the earth dams is controlled by two approaches: The first approach involves reduction of the quantity of seepage by constructing sheet pile (steel, wooden), cutoff wall, slurry trench, clay sealing, upstream impervious blanket, grout curtain, concrete wall, diaphragm wall, etc. The second approach
involves providing a safe outlet for the seeping water, which still enters the earth dams or the foundation. This may be achieved by providing the downstream face filters, such as filters, drains, sand drains, stone columns, ditches, and relief wells. Seepage through earth dams with Internal Cutoff is studied: experimentally using Hele- Shaw Model, mathematically using the complex function and numerically using SEEP/W. Effect of internal cutoff on seepage discharge, DROP in phreatic surface and minimum seepage face length of the earth dams is analyzed. Dimensional analysis method is used considering all the dimensionless parameter which affect on seepage discharge and seepage face length. Empirical equations for seepage discharge and seepage face length are deduced. Experimental work is carried out in the laboratory of Irrigation Engineering and Hydraulics Department, Faculty of Engineering, Alexandria University, Egypt on a Hele-Shaw model. About 150 experiments are performed on the model to study effect of the inclined cutoff width, optimum position of vertical cutoff and effect of the pervious layer depth. Minimum seepage discharge, maximum DROP in phreatic surface and minimum seepage face length experimentally measured and drawn. Complex function is used to deduce the complex potential of earth dam with internal cutoff to establish equations of equipotential and stream functions. Equation of phreatic surface is also established. Then seepage discharge and DROP in phreatic surface can be theoretically calculated. Numerical Model using SEEP/W is used to calculate the total seepage discharge of earth dam with internal cutoff. Comparisons between results deduced from SEEP/W and bothexperimental and mathematical one are made. Conclusion of the present work includes: cutoff width has a small effect on the relative seepage face discharge, it is proved that optimum position of cutoff exists in the middle of the dam base width, and seepage face length can be reduced by increasing depth of pervious layer.