Study On Temperature Control And Crack Prevention Of Concrete Of Arch Dams

Concentrated on the questions of temperature control and crack prevention studies on concrete of arch dams, simulative calculation theories of temperature and stress fields of concrete of arch dams are systematically studied in theory and practice, the temperature control of Huaguangtan arch dam is analyzed and studied in detail. The main contents are as follows:1. Much physics mechanics characteristic of concrete is overviewed, which is used in calculation of the temperature field, moisture field, stress field and temperature control and crack prevention.2. Mass concrete structure is constructed by layers. The physics parameters and the thermal boundary conditions of concrete change with time. Therefore the whole construct process should be simulated and parameters of materials, boundary conditions and mesh should be changed with time in computing. An effective method for computing the temperature field and stress field of mass concrete is dissertated. The method can simulate precisely for mass concrete, which constructed by layered, The 3-D temperature field and stress field simulative calculation program is designed and implemented.3. Pipe cooling is one of the most temperature control measures of concrete of arch dams. The 3-D simulative calculation program concerning temperature field and stress field applying pipe cooling is conducted by adopting more advanced simulation technique. Many kinds of methods of pipe cooling are dissertated and compared, and the effect of pipe cooling is analyzed exhaustively.4. It dissertates the principle of genetic algorithm. The temperature parameters of concrete are back analyzed by this method in the scientific research of Baoying pumping station.5. It expounds harmfulness and cause of crack of concrete of arch dams, and measures of crack prevention in such structures are suggested.6. Based on Huaguangtan arch dam project, the studies of relate method and practical application are developed. The effect of cold wave, layer thickness of construct and sluice to temperature field and stress field are studied. This paper analysis the effect of the first stage cooling and the second stage cooling. Pertinent measures of temperature control and crack prevention are suggested, settling the practice problems in projects.