Research on Time Control for Water Cooling Lining Concrete of Hydraulic Tunnel

The successful experience of controlling the timing of water cooling for dam concrete cannot be well applied to temperature control and crack control of thin-walled lining structures. Taking the lining concrete of hydraulic tunnel as an example, the Finite Element Method was applied to study the relationship between the maximum inside temperature, the maximum inner surface temperature difference, the maximum tensile stress, the minimum crack resistance safety factor, the cooling rate and cooling time. The results indicate that the best time for water cooling and temperature control is when the concrete covers the cooling water pipe and the water starts to flow, and the maximum internal surface temperature difference occurs and ends immediately. Field tests were carried out in units 144-145 of the upper flat section of the 1# spillway tunnel of Baihetan Hydropower Station, and combined with Finite Element Method simulation, the scientific and economic effectiveness of temperature control and crack prevention was verified, which can be applied in practical engineering.