Research On The Causes Of Embankment Dam Accidents And Data Analysis Of Piezometric Tube

Dams play an important role in flood control, generating electricity, irrigation, water supply, shipping, breeding industry, tourism, ecology and so on. Among the various kinds of reservoir dams, embankment dam is the most commonly used one. About 90 percent of the 85,000 reservoirs in China are embankment dams, Most of embankment dam was built in "Dyuejin" period and "Ten Years of Mess" period. Without much experience, many of the projects were conducted and completed in the way of "Three Sides" and therefore, though still functioning, have such serious problems as low standard of flood control, poor project quality, and many hidden dangers. Many accidents have made it clear that the disaster caused by flood is unimaginable once a dam breaks. It is an important task for water experts to do research on how to prolong the longevity of water projects and prevent unexpected dam accidents. On the basis of analyzing the causes of embankment dam accidents, this essay puts forward the new idea of analyzing observation data of piezometic tube in embankment dams. The main contents are as follows:I. After investigating embankment dam construction and analyzing the cases of accidents, the essay elaborates the main factors that are related to the safety of embankment dams, types of accidents and the causes of accidents, which can provide theory and experience for safety government and strengthening of a dam.II. This essay analyzes the deformation mechanism of embankment dams and inter-relationship between the factors which affect the safety of dams, providing theory for choosing independent variables of mathematical models.III. There are two conditions in the data analysis of piezometric tube observation: confined seepage flow and unconfined seepage flow. In the former situation, the potential of piezometric tube is used as dependent variable in setting up statistical model, while in the latter situation, water level of piezometric tube is used. Four aspects of this part have been done as follows:A) Setting up statistical analysis model for observing data from damsunconfined seepage flow. Taking the water level of piezometric tube seeping in dam as a research object, the essay sets up a general data analyzing model between the water level of piezometric tube and the water level of upper and lower reaches, time effect and rainfall componentB) statistical analysis model for observation data from dams confined seepage flow is built. Through researching the potential of piezometric tube in confined seepage flow field, a general data analyzing model between piezometric potential and relief well and drain hole and time effect component is establishment.C) statistical analysis models is built by multivariate stepwise regression analysis and partial correlation analysis, multivariate stepwise regression analysis make the best regression aquation and partial correlation analysis assert the coherence among every components.D) Based on observation data of piezometric tube from the dam foundation and embankment of Qingshan Reservoir, the correctness of the data analyzing model has been tested and the adopted analyzing method with the actual safety evaluation method of Qingshan Reservoir compared. Furthermore, the observation data of piezometric tubes in Qingshan Reservoir dam before and after its strengthening are analyzed by this model.