| 1. |
Grout curtains are a structural element of the underground contour of dams with a limited service life. A gradual decrease of the modulus of deformation of the foundation and deterioration of its other characteristics occur as a result of leaching of the cement.
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| 2. |
Estimation of the life of grout curtains and determination of the overhaul period should be carried out differentially on the basis of particular values of the rate of the leaching process. For example, the average rate of removal of calcium oxide from the grout curtain in the foundation of one section of the Sayan-Shushenskoie dam is 7.5 and of the Zeya dam, 9.4 mg/sec.
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| 3. |
It is necessary to broaden the study of the behavior of grout curtains at operating concrete dams to establish performance criteria at various stages of life of the structure.
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| 4. |
The volume of grouting works on a grout curtain should be assigned on the basis of the required life of grout curtains, assuming that the life is proportional to the square of their thickness.
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| 5. |
When designing the underground contour of dams, the parameters of the drainage system should be assigned with consideration of the destruction of the grout curtains occurring and prevention of overloading of the drainage systems. At the dam designing stage it is necessary to provide the possibility of conducting effective restoration of the serviceability of grout curtains.
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Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 7, pp. 21–24, July, 1992.