Control of Seepage through Earth Dams Based on Pervious Foundation Using Toe Drainage Systems

Abstract

Many dangerous effects arise from seepage through earth dams based on pervious layer. Therefore, the dam embankment must be provided with seepage control measures to avoid such effects. In the present work, different control methods were used such as flat slopes, toe drainage systems, and a catch drain in the tail water. The hydraulic performance of each control measure was evaluated using the analytical solutions, previously developed, to estimate the seepage quantity ( q ), the height of seepage surface ( h 3 ), and the coordinates of the free surface ( h x ). Study was conducted on a physical model for a dam embankment having a top width ( b ) = 10.0 meter, height ( H d ) = 30.0 meter, and slope factor ( m ) = 1.5. The obtained results were analyzed and presented in dimensionless charts. Results showed that, the used control measures possess a great effect on the characteristics of seepage through earth dams based on pervious foundations. A comparative study was conducted between the studied toe drainage systems to enable the designers the better choice for design purposes.