Temperature monitoring and cracking risk analysis of corridor top arch of Baihetan arch dam during construction period

•Adopt DTS system to monitor the temperature of corridor top arch of Baihetan Arch Dam.•Finite element method is used to simulate the thermal stress and cracking risk of the top arch concrete of the corridor.•Feedback analysis of the top arch of the corridor is carried out to meet the requirements of temperature control and crack prevention. During the construction period, the phenomenon of stress concentration at the top arch of the corridor is obvious, which is easy to produce surface cracks. As a consequence, it is of great importance to research the temperature and stress changes of the corridor during the construction period, analyze the cracking risk of the top arch of the corridor, and put forward the corresponding temperature control measures. This study, the temperature gradient test of the top arch of the corridor is conducted, utilizing the distributed optical fiber buried in the construction place of Baihetan Arch Dam. Considering the influence of creep, the finite element method is used to simulate the thermal stress of the top arch concrete of the corridor, and the cracking risk of the top arch concrete is evaluated. According to varying temperature drops, it is suggested that different temperature control measures to maintain the heat of the top arch of the corridor. The recommended measures are as follows: when the temperature drops by 6 °C, 12 °C and 18 °C, the roof vault of the corridor shall be covered with 20 mm, 40 mm and 50 mm polyethylene insulation covers respectively, and the interior of the corridor shall not be sprayed with 20 mm and 40 mm polyurethane respectively. Temporary storm doors shall be set at the entrances and exits of the corridor. The control measures of temperature can meet the requirements of temperature control and crack prevention of the concrete of the dam body of Baihetan Arch Dam.