Study On Real-time Temperature Stress Control Of Mass Concrete

With the rapid development of economic and the great increase of efficiency in hydropower resources using, our country has build a large number of large-sized and medium-sized water conservancy projects in the last 20 years. The dam concrete is a typical kind of mass concrete, and in order to prevent the great damage to the dam structure caused by cracking, we must pay much attention to the temperature control and stress control during the construction period and operation period. We commonly use the method of placing internal water pipe to cool down inside the concrete. The study of the real-time temperature field and stress field in concrete dam during the period of water cooling, can effectively prevent large tensile stress, and also provide a meaning reference for engineering to take effective measures in time. This paper developed a temperature and stress finite element simulation program, using GPU parallel computing, which is based on the CUDA platform. By analyzing the data of the Xiluodu dam and laboratory experiment, we find the evolution of temperature field and stress field in concrete, and based on this, we put forward a model of temperature stress control model. The main work we have done in this paper including the following aspects:(1) We pointed out that the shortage of concrete–water heat exchange system in domestic and foreign, and shows the research status and shortage of temperature stress research from three aspects: the internal crack evolution mechanism; the calculation of the stress field and the temperature stress control theory; the integration of real-time monitoring and simulation in the stress analysis and feedback control.(2) We derived the finite element simulation method of temperature field, stress field, and illustrated the calculation process and main structure of the program. We explained the realization process processing of boundary condition and construction process in detail.(3) By calculating an example, we compared the results of CPU program and the commercial program MIDAS, and verified the accuracy and efficiency of the GPU program.(4) By using the experimental data to simulate the water temperature distribution of concrete, and using the temperature data of concrete measured by the thermometer to interpolate the temperature field distribution. We compared the results by numerical simulation and the actual temperature results by monitoring, and discussed the source of the difference.(5) Based on the analysis of the measured temperature field in Xiluodu dam, we summed up the distribution and evolution law of temperature field, stress field.(6) By analysising the stress of Xulong dam, we concluded the important area for temperature control of the dam. And we proposed the stress control and early warning model based on real-time monitoring and simulation, which uses the index of stress index for control.