Temperature monitoring test and thermal analysis during construction of deep orifice of arch dam

In the low-temperature season of Southwest China, concrete of orifice is easy to crack during pouring, and the superficial heat preservation of dam is needed. In this paper, the temperature gradient monitoring test of deep orifice of Baihetan Dam is carried out to obtain measured temperature data based on the distributed optical fiber sensing technique. Based on monitoring data, a finite element model of deep orifice of pouring blocks considering thermal insulation materials is established. By comparing calculated temperature with measured temperature, accuracy of the simulation model is verified. The temperature and stress of deep orifice with or without thermal insulation measures are analyzed, considering the thermal insulation effects of different thicknesses and different types of thermal insulation materials. The results show that when the insulation measures are not covered, the average temperature difference between day and night exceeds 2 C-degrees, and the average temperature difference between day and night is within 1 C-degrees after coverage. Using 3 cm or 5 cm polyethylene coil at the top surface and the transverse joint surface of pouring blocks, and spraying 3 cm or 5 cm polyurethane at the upstream surface of pouring blocks for thermal insulation can effectively prevent the temperature cracks.