Research On Simulation Of Thermal Stress And Crack Prevention Technique At Construction Period Of Thin Walled Hydraulic Concrete

When the stress exceeds the tensile strength of concrete, there will be a crack,and the crack of construction period is mainly the temperature crack and dry shrinkage crack. Thin walled concrete is widely used in large-scale water conservancy infrastructure of China.Due to its irregular shape and size, the uncertainty of construction conditions and complicated external factors, large stress of concrete in the construction period will appear. It can influence the utility of hydraulic structure.Bace on the introduction of the background and the present status of the thin walled concrete temperature control and crack prevention, The characteristics and calculation methods of temperature cracks are summarized in this paper.The change law of thin walled hydraulic concrete structure’ temperature and stress field under different conditions are simulated and crack control technology of the thin-walled hydraulic concrete in construction period is studied and discussed, the main research results are as follow:1. For the issue of layered pouring of concrete gate pier, the effect of layered pouring on stress of gate pier is analyzed by analysis of thermal stress of gate pier in the process of layered pouring, the actual example was calculated and the method of controlling the pouring interval and optimizing the engineering construction is put forward.Simulate and analyse different matching schemes of layered pouring height and temperature stress of different pouring height of concrete gate pier, propose the best layered pouring scheme.2. The simulation of pier concrete structure with wire fiber conditions.Combined with the finite element theory, the temperature field and stress field of the gate pier under different temperature reinforcement are simulated and analyzed, and some useful suggestions are put forward for the practical engineering of the temperature reinforcement.3. Taking the lining of the diversion channel of the south to North Water Diversion Project as an example, the changes of temperature stress in lining of different thickness, different placement temperature and different size of lining areanalyzed.According to the change of the maximum temperature stress of mass channel concrete lining, combined with the strength of concrete lining, the optimum cutting time of the channel lining is determined under different construction conditions.Solve the humidity field of lining, determine the best form removal time of lining.At the end of this paper, the control of temperature stress and crack of the thin wall concrete in the construction period are summarized, and the future work is prospected.