Small temperature difference in the middle and later water cooling stages of RCC dam

Abstract

Abstract Water cooling is the main measure to reduce temperature cracks in RCC dams. But later cooling usually means reducing water temperature rapidly after 120 days of the concrete age, which may cause larger self stress and tensile stress inside the concrete. The small temperature difference cooling can advance the starting time of middle and late cooling stages, and reduce the temperature stress effectively. However, the difference of temperature stress produced by different middle and late stages water cooling methods is large. It is necessary to analyse precisely how to use the small temperature difference methods in the middle and late cooling stages of dams properly. The cooling methods of RCC dam in the middle and late stages are studied by using the self-developed 3-D FEM floating mesh method temperature controlling simulation program. Result shows that when the small temperature difference is used to cool the dam in the middle and late stages, the temperature and temperature stress of the dam reduces obviously. When the age of the concrete is over, the dam should be cooled immediately, several levels of water temperature should be set in the middle and late cooling stages, the temperature of the water should be reduced slowly, which can reduce the temperature and temperature stress of the dam effectively. Study result will provide a favourable reference for practical projects.