Minimizing of seepage beneath earth fill dams using cutoff wall

Earth fill dams must be constructed to stand safe and stable against the acting forces, in particular, that based on pervious foundations. Seepage flow beneath such dams presents the most dangerous effects on dam stability. To avoid these effects, the seepage flow must be controlled. One of the most efficient control methods is providing the dam with a cutoff wall, specially those based on pervious foundation of moderate finite depth. In the present work, the effect of the main parameters, on the seepage characteristics was studied, such as, the cutoff wall depth, the foundation depth, and effective head. The effect of the above parameters on the seepage discharge, the loss of head along the cutoff wall, and the height of seepage surface was analyzed numerically using the finite element model. A computer program was prepared to handle with input and output data. Results showed that the cutoff wall has a great effect on the seepage characteristics beneath an earth dam based on a pervious foundation of a finite depth. The obtained results are presented in a dimensionless form either through graphs or empirical equations, given in a dimensional form. © Faculty of Engineering Alexandria University, Egypt.