Theoretical Study On Temperature Control And Crack Prevention Of High RCC Arch Dam

After the construction of Wanjiakouzi RCC arch dam, 157.6 m high, in Yunnan province, the world record of RCC arch dam's height will be refurbished. Study on temperature control and crack prevention of height RCC arch dam during the period of building and operation is a key question. However, at present, the full precise process simulation analysis for RCC arch dam still meets many difficulties, which includes a lot of challenging research. Cooperated with Wanjiakouzi RCC arch dam, some research work about temperature control and crack prevention are performed as following:1. Determination for Initial Temperature on the Joint Face of Pouring Concrete by Stages.Based on conservation of energy law, the physical cause, which lead to calculative errors of temperature fields as different initial temperature on the joint face , was analyzed. According to energy conservative principle, the formula of initial temperature on the interface of old and newly poured concrete is derived.2. Design of comparative test for simulation of hydration heatCompared the result of theoretical analysis and the numerical analytical of finite element method, a comparative test is designed to exactly distinguish two commands about simulation of hydration heat in ANSYS.3. The simulation and research of artificial cooling with nonmetal pipeThe artificial cooling with nonmetal pipe is simulated and researched by finite element method. The water temperature and necessary time for artificial cooling effect of first stage is analyzed and a curve of concrete adiabatic temperature rise in various water temperatures is acquired. The artificial cooling effect of second stage, the stress field around pipe and its range are analyzed under variable water temperature condition.4. The simulation of temperature control and crack prevention of Wanjiakouzi RCC arch damBased on theory of parameterization technique for FEM, the code for parametric modeling and analysis for arch dam was developed to simulate the temperature field and stress field of Wanjiakouzi arch dam. Cooperated with this dam, the temperature field and stress field of dam is analyzed under the condition of permanent superficial thermal insulation with foamed plastics. The calculate results reveal that the temperature field of newly poured concrete distribute uniformly on the whole. Air temperature change is the most significant factor, if superficial thermal insulation is adopt permanently, the influence of air temperature change on superficial of dam would be reduced sharply, then most crack in superficial of dam would be avoided.