Rollcrete upstream wing wall

Abstract

1. The construction ana operation of the upstream wing wall of the Tashkumyr hydroelectric station confirmed the possibility and expediency of using lean rollcrete and simple designs for dams. After 3 years' operation the wall is in a completely satisfactory state. 2. The use of rollcrete with a cement content of 80–120 kg/m3 during concreting by the technology proposed and perfected during construction of the wall provided the obtainment of concrete grades M100180–M200180 (classes V7.5–V15). When designing rollcrete it is necessary to take into account its increased nonuniformity — the coefficient of variation of the strength values of the concrete of the wall was 0.20–0.25. 3. A uniform temperature regime with low values of the maximum temperatures is characteristic for rollcrete masonry. The measured temperature of the wall masonry corresponded to those calculated. The possibility of predicting the temperature regime of the rollcrete mass during its construction is thereby confirmed. 4. When designing hydraulic structures it is necessary to take into account the anisotropy of the density of rollcrete masonry. Horizontal joints have a high permeability, which requires either a special technology of forming them or structural protection of such masonry with the outer zones made of vibrated concrete. It is expedient to protect the rollcrete masonry with a gunite layer mainly for temporary dams. 5. The main designs adopted for the dam of the Tashkumyr hydrostation were tested successfully during construction of the wall.