Combined static and seepage calculations of the Bratsk concrete dam

Abstract

1. The results of combined static and seepage calculations of the powerhouse section of the Bratsk dam shows a satisfactory agreement with data of on-site observations with respect to the length of opening of the contact joint and diagram of seepage heads in the contact zone, stresses and displacements of the structure, opening of the column joints, and seepage discharges in the foundation. The closest agreement of the calculated and on-site data was obtained with consideration of stages of constructing the dam in the calculations, which corresponds to the real working conditions of the structure. 2. The agreement of the results of the calculations and on-site data confirm the possibility of mathematical modeling of the behavior of real structures on rock foundations with consideration of the complex set of external factors: stages of construction, presence of joints and cracks in the dam and foundation, seepage along fractures, contact joint, and in entire blocks of the rock, elastoplastic behavior of the material, and temperature effects. 3. Calculations of the SSS, strength, and stability of the Bratsk dam with consideration of the real strength and deformation properties of the materials show that the lightweight powerhouse sections are in a satisfactory operating state. The minimum value of the coefficient of stability against shear for the examined calculated cases is 2.21. 4. The picture of the seepage regime of the dam foundation confirms the data of on-site observations of the high effectiveness of the drainage system and possibility of eliminating a grout curtain in low-permeability rock masses. In this case, the diagram of the seepage heads over the base of the structure differs from the standard one. 5. Opening of the contact joint and decompression of the foundation under the upstream face of concrete dams leads to worsening of the scheme of the static behavior of the structure and requires adequate reflection in the practice of designing these engineering structures.