Study on Temperature Drop Effect Caused by Low-temperature Pouring of Concrete Dams

Low-temperature concrete pouring on dams causes sudden temperature drops on the surface of the previously poured concrete, thus inducing thermal cracks. In this study, a field test and a numerical calculation were performed on the temperature drop effect caused by low-temperature pouring to prevent thermal cracks in concrete dams. Firstly, a small spatial-scale temperature-gradient monitoring scheme was designed for concrete dams based on the distributed temperature sensing (DTS) system. Secondly, a field test was conducted during the construction period of the Baihetan extra-high arch dam using this scheme, analyzing the temperature response of low-temperature pouring. Finally, a numerical simulation model was established on the temperature field and stress field of the dam, studying the temperature drop effect caused by low-temperature concrete pouring under different construction conditions and its countermeasures. The results indicate that the temperature monitoring scheme proposed in this paper could effectively capture the temperature drop effect at a small-spatial scale caused by low-temperature pouring. This effect, as a negative impact on crack prevention of dam concrete, is effectively weakened using uniform surface-flowing water cooling with a temperature of 22–24°C.