Research On Temperature Field And Thermal Stress Characteristics Of RCC Dam In Large Temperature Difference Area

The research on temperature field and thermal stress characteristics of the roller compacted concrete(RCC)dam in the large temperature difference area reveals the generation mechanism of cracks and puts forward specific temperature control and crack prevention measures,which is of great significance to solve the thermal cracks of RCC dam in the large temperature difference area.This paper takes a reservoir in Inner Mongolia as engineering background,carries out research on temperature field and thermal stress distribution characteristics of RCC gravity dam during construction period based on monitored data,parameters tests,and actual casting conditions,and analyzes the evolution law of dam temperature and stress.At the same time,the paper also identifies the dam cracking area,cracking causes,influencing factors,and characterization variables,and determines the critical value of temperature difference and allowable temperature difference between upper and lower layers.Besides,the paper also explores the influence of some typical factors on large temperature difference,and also puts forward a series of targeted temperature control and crack prevention measures.The results show that the normal concrete temperature and tensile stress of the dam are high,and it is predicted that there is cracking risk on the surface of the gallery,upstream and downstream panels.The main reasons for cracking are a large amount of normal concrete cement and change of ambient temperature,etc.However,the temperature and tensile stress in the RCC area are low and there is no risk of cracking.In the large temperature difference area,it is suggested that the crack safety factor of the dam should be increased to over 1.69,and the maximum temperature,internal and external temperature difference,maximum tensile stress and crack safety factor can be used as characterization variables.Moreover,it is found that the allowable temperature difference limits of the upper and lower layers of RCC in restraint zone,normal concrete in the unconstrained zone,and RCC in the unconstrained zone are 14.7 ℃,12.1 ℃,17.3 ℃,and 14.5 ℃,respectively.In addition,the influence rule and optimum range of internal and external factors of the RCC dam in the large temperature difference area have been determined,and a series of temperature control and crack prevention measures have been put forward.This study can provide theoretical reference for the design,construction,and disease risk control of RCC dams in the large temperature difference area.