Analysis of Seepage and Upstream Slope Stability of Earth Dams Using Geo Studio Model: Haditha Dam as a Case Study

Abstract

Earth dam is a popular engineering structure that can be constructed with different designs and mechanisms in multiple applications, such as irrigation, hydropower, water supply, recreation and flood control. According to the historical failure cases, seepage through and under an earth dam is one of the most significant factors in earth dam failures. Therefore, the need for the dam to be safe and stable requires a good design and analysis of seepage problems. The present study aims to analyze the seepage and slope stability of the upstream slope of Haditha Dam by using the Finite Element Method through one of the geotechnical engineering model named (GEO-STUDIO). The accuracy of the results presented by the program were tested by using four physical models at study state conditions; two for homogeneous earth dam and two for non-homogeneous earth dam, and comparing the results obtained with the results of the program. The results showed that the correlation coefficient of the seepage line is more than 96%, and the relative error of the seepage rate is less than 3%, which indicates the accuracy of the results provided by the program. The seepage analysis of Haditha Dam shows that the seepage line remains within the dam's body with a seepage rate of 74.839 m3 /day/m at the maximum level of the reservoir. In order to understand the most influential region in the cross-section of the dam, five additional cases are input in the program related to the region's effect on the seepage results which were the dam without; asphaltic concrete diaphragm, core, grout curtain, core and asphaltic concrete diaphragm, and core and grout curtain and asphaltic concrete diaphragm. As a result, it was found that the grout curtain is the most influential region on the seepage results, wherein its absence, the phreatic line intersects the downstream slope of the dam and the seepage rate