Seepage analysis in embankment dam under static condition using numerical model (case study: Legemera Earthen dam)

Abstract

Seepage constitutes a significant factor in the failure of embankment dams. The analysis of seepage is a crucial consideration in dam safety. To address this concern, a finite element method was employed using the computer program Geo Studio, specifically its sub-program named SEEP/W. This method was utilized to ascertain various aspects, including the surface seepage line, the quantity of seepage through both the dam and its foundation, measurements of seepage velocity, distribution of pore water pressure, total head, pressure head, and exit gradient of a homogeneous earth dam. The study focused on Legemera dam, situated in Borena Woreda of the Amhara region, serving as a representative homogeneous earth dam. The dam, as originally designed, underwent analysis using the SEEP/W 2012 program. Subsequently, multiple analyses were conducted to investigate seepage through Legemera dam under different conditions, namely, normal water level and maximum water level. The findings revealed that during the maximum water level scenario, the quantity of seepage, seepage velocity, and exit gradient were higher compared to the normal water level case. This suggests that as the water level in the upstream area of the dam increases, there is a corresponding increase in the amount of seepage, velocity of seepage, and exit gradient.