Stress-strain state of the Sayano-Shushenskoe dam during filling of the reservoir

Abstract

1. The results of monitoring by means of long-term on-site observations and inspections indicate the satisfactory state of the gravity-arch dam during its construction and simultaneous staged filling of the reservoir. The change in the main parameters (deformations, stresses, seepage heads and discharges) characterizing the static behavior of the structure is occurring in conformity with the changes in the hydrostatic load, temperature effects, and concreting, and grouting the joints of the dam. 2. Staged construction and loading of the dam substantially affect its stress-strain state. Construction of the dam in an incomplete profile (the long absence of the fourth columns, toothing on the downstream face, zones of unsealed concrete) under conditions of a constantly increasing hydrostatic load leads to a redistribution of arch and cantilever stresses, to a decrease of compressive stresses in the fourth columns, and to an increase in the third. The actual values of the arch stresses in the first column of the dam at an elevation of the upper pool level close to 500 m are commensurate with the calculated at the normal pool level. This is explained by the fact that owing to the toothings existing on the downstream face the arch on the second columns is not closed. A considerable role in the construction and construction-operating periods is played by the temperature and moisture factors, increasing the compressive stresses on the upstream face compared with the design. As a result, the upstream face of the dam in past stages of filling was compressed practically over the entire height [4]. 3. The “curtain-drainage” cutoff system provides an effective reduction of head on the upstream face of the foundation. Zones of an excess head were not found within the main part of the underground contour of the dam. The discharges of the drain devices do not exceed the design assumptions.