Effect of Core Angle in Earth Dam on Seepage Characteristic (Numerical Model)

Abstract

Seepage through earth dams causes seepage forces, pore water pressures, and hydraulic gradients. These forces could create piping, sloughing, or sliding, which could fail an earth dam if not kept within the allowable ranges. Consequently, seepage analysis is critical in the design of any hydraulic construction. In this study, the finite element modeling method by SEEP/W software was used to examine seepage characteristics through earth dams with the central core at an angle of (α=90°,50°, and 30°) for different dam materials and geometries under steady-state conditions. The results indicated that the reduction of seepage through the earth dam body increased as the core slope decreased, while it increased with increasing the permeability ratio and the upstream head. The core slope angle of 30° was the most effective of those evaluated in decreasing seepage discharge, exit gradient, and top seepage line at the core's faces. Also, using the statistical analysis program SPSS to develop empirical equations, to estimate seepage through the earth dam with a central core and top seepage intersecting core slope. The correlation coefficient (R2) was greater than 0.95 and 0.98 for the suggested seepage and top seepage equations line, respectively.