Modelling of Seepage and Slope Stability Analysis of Ribb Embankment Dam, Ethiopia

Abstract Safety against seepage is one in all the primary important steps for checking the possibility of failure of embankment dam and the stability of an embankment dam depends on its geometry, its components, materials, properties of every component, and therefore the forces to which it's subjected. This paper presented seepage and slope stability analysis against Ribb dam safety using finite element-based PLAXIS software, and so the result was compared with different standards. PLAXIS is alternative software that will be used for evaluating the protection of embankment dams due to seepage conditions. The simulated results showed the common rate of flow of seepage through the body of the dam at normal pool level was equal to 5.05*10−6 m3/s/m and through the foundation of the dam was 3.00*10−6 m3/s/m. According to Look (2014) recommendation, the seepage results within the tolerable limit. The results of the factor of safety were considered too different loading conditions. The factor of safety results during the end of construction for both static and dynamic stability analysis were 1.3063 and 1.2226, respectively. For steady-state conditions, the factor of safety obtained for static stability analysis was 1.2604, and also the dynamic analysis 1.1803. The rapid drawdown condition is analyzed with a normal pool level of 1940 m lowered to 1900 m or rapidly reduced 57% of the reservoir water. The analysis results showed that the factor of safety for the static, and dynamic analyses were 1.2021 and 1.0662, respectively. Using different recommended design standards: United States Army Corps of Engineers (USACE), British dam society (BDS), and Canadian dam association (CDA) the slope stability analysis of the Ribb embankment dam at all critical loading conditions is safe.