Document Type : Original Article
Authors
1
Assistant Professor of Azerbaijan Shahid Madani University - Department of Civil Engineering, Tabriz, Iran.
2
Ph.D. Student, Civil Engineering - Water and Hydraulic Structures, Maragheh University, Maragheh, Iran
3
Master's Student, Civil Engineering - Water and Hydraulic Structures of Azerbaijan Shahid Madani University, Tabriz, Iran
Abstract
Earth dams, as critical infrastructure, play a vital role in water resource management, flood control, and supplying water for agricultural and domestic use. A key challenge in these structures is controlling seepage and internal erosion, which significantly impact their safety and durability. The use of cutoff walls can enhance hydraulic performance by reducing seepage flow and hydraulic gradient. This study investigates the effects of cutoff wall depth (9, 12, 15, and 16 meters) and thickness (1, 1.5, 2, and 2.2 meters) on seepage flow, hydraulic gradient, and uplift force, based on the specifications of an earth dam in East Azerbaijan, using numerical modeling (Seep/W and GeoStudio). The results indicate that increasing the cutoff wall depth to 15 meters reduces seepage flow by 53.4%, while increasing the thickness to 2 meters results in a 33.71% reduction. Further increases in depth and thickness have negligible effects on seepage reduction. Optimizing the cutoff wall dimensions leads to a 51.21% reduction in hydraulic gradient at a depth of 15 meters and a 22.33% reduction at a thickness of 2 meters. Additionally, uplift force increases by 4.44% and 3.81% with increasing depth and thickness, respectively, which has no significant adverse effect on dam stability due to the dam body’s weight. Economic analysis reveals that optimizing cutoff wall dimensions can save 53% in excavation costs and 33% in additional expenses, resulting in savings of 45 billion IRR in the construction of the studied earth dam. This research demonstrates that selecting an optimal depth of 15 meters and thickness of 2 meters effectively reduces seepage, improves hydraulic performance, and lowers costs.
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