| With the persistent steady high-speed development of economy in China, more and more hydraulic and hydropower projects will be constructed in order to explore the water resources and resolve the water problems. At the same time, China is a big country at building dams in the world. Since 1949 about eighty seven thousand dams were constructed, and most of them (about eighty thousand) were constructed from 1950's to 1970's, which laid a good foundation at hydraulic and hydropower construction and played an important role in county economy. Because of the factors of hydrology, geology, design, construction quality, management and maintenance, materials' aging and so on, many dams have hidden troubles, it will not only influence the benefit of the projects, but also threaten the safety of the lives and wealth of down stream. Once dam burst, it will result in disastrous tragedies and great economic loss. As the time pass by, there will be more and more old and sick dams, and the safety problems of dams will more and more stand out, and will become the focus problems of attention and solution in this century. Dam safety monitoring plays a very important role in controlling the safety conditions, discovering hidden trouble, testing the design and construction in time. How to simulate the dam's work conditions reliably with amount of monitoring data and through back analysis with them, how to get the material character's evolutionism of dam and its foundation to provide the scientific basis for operating safely, prediction and forecasting, strengthening and enriching design theories. The above problems are worth thorough studying. In this paper combining the distortion and up-pressure prototype monitoring data during Shizi Tan Dam's operation in about 40 years, and on the basis of Stat. analysis for long-term series inspection, builds the mathematics model of dam distortion, foundation up-pressure and seepage discharge through dam allowing for primary factors such as water level, time and temperature and so on, and makes the scientific evaluation for the safety of dam distortion and seepage stability. Through the testing by the monitoring data, it is proved that the model is reasonable and the precision is high, and the Shizi Tan Dam's working conditions are reflected precisly. At the same time, on the basis of the analysis for effects on the simulation of factors, according to the formation character of function of time, temperature, contrastive analysis has been done for different factors. The paper also tests the reasonability of factor function of the model. The research results are valuable in instruction and extending applications to the monitoring analysis for similar projects.Because the monitoring variables of dams and its effect are hard to formulated obviously, the BP neural network model of dam distortion and up-pressure is constructed in this paper. Through testing by the monitoring data, it is proved that the precision could meet the requests of the projects and it is a good model for forecast.According to the structure specialty of Shizi Tan Dam, the plain finite element calculations are done by adopting D—P rule and Ducan—chang model separately. The comparing analysis with monitoring data demonstrated that Ducan—chang model is more reasonable. According to the back analysis for six parameters, parameters including ,,,,, have rather different effects on dam stress and distortion, especially parameters ,,. Compared with the test result, these parameters of back analysis change a bit, but are still in the range of materials parameters. And the distortion separation law of back analysis is accord with that of the monitoring data, and their value are close. It means that the parameters of back analysis were reasonable and could reflect the dam body material's mechanics character during about 40 years operation of Shizi Tan Dam. In China, the back analysis of hydraulic structure such as dams was less carried out, and many problems were still in research. The back analysis of pa... |
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