Criteria for selecting and assigning optimal temperatures for grouting joints

Abstract

1. The selection and assignment of optimal temperatures for grouting joints are important for the thermal stress state of the dam during construction and its operation. 2. Three temperature zones can be distinguished (vertically) in reservoirs of high dams: upper, where considerable variations of the average monthly temperatures occur during the year; middle (transition), where gradual fading of temperatures occurs; lower, where almost no variations of the temperature regime occur during the entire year. 3. In deep reservoirs the lower temperature zone, occupying more than 0.5H, is characterized by isotherm T=3.5°C. The long effect of this zone on concrete of the upstream face of the structure, just as the effect of higher zones, should be taken into consideration when planning and performing the works. 4. To improve the stress state of the structure and to provide its general solidity, it is recommended to assign individually several temperatures of sealing the joints being grouted depending on their position in the dam. 5. Six optimally selected temperatures of sealing the joints located in the region of the upstream face (upper, middle, and lower zones), downstream face, contact part (dam foundation), and core part can correspond best to the existing temperature regime of the dam's concrete.