Influence of Drainage Measures on the Uplift Resistance of the Foundation Joint of a Gravity Concrete Dam

<p><em>A common characteristic of concrete as a material used in the construction of dams and the surrounding rock mass, on which such structures are typically founded, is the presence of voids within the material. Buoyancy, as the load exerted by water in the voids of the foundation medium and concrete that presses against the structure, must be reduced and kept at a level where the stability and performance of the structure will not be compromised. The methods most commonly applied to reduce the buoyancy at the foundation interface include the use of an injection curtain on the upstream face and drainage boreholes downstream of the curtain.</em></p> <p><em>The seepage pattern analysis presented in this paper is illustrated through different calculation scenarios and under varying boundary conditions. The analysis was conducted on the structure of the additional hydropower plant of the gravity concrete dam "Iron Gate II," where the initial seepage pattern was analyzed using the finite element method (FEM) model, composed of the concrete section of the additional plant and the associated rock mass. Quantitative parameters illustrating the effects of seepage pattern improvement in other calculation scenarios were obtained after incorporating elements such as the injection curtain and drainage boreholes into the FEM model.</em></p> <p><em>A comparative analysis, conducted under two different boundary conditions, compared the buoyancy values in five different calculation scenarios and calculated the safety factors for the analyzed scenarios. Based on the results, conclusions regarding the effects of changes in the seepage pattern were drawn. In addition to the calculations, the paper also presents a theoretical review of the Eurocode standard, specifically focusing on the calculation of safety coefficients for flotation, which was implemented in the software and used during the analysis presented in this paper.</em></p>