Evaluation On Durability And Safety Of The Dams

According to the features of earth dams, on the basis of the previous worker's work, this article changes the evaluation of quality into that of both quality and service life, and composing actively the blind number theory and safety and durability analysis, sets up safety durability evaluation methods and engineering applications on earth dam as durability evaluation system, reliability analysis of dam slope, reliability analysis and evaluation of seepage stability, seepage control method based on muddy water seepage theory, complying with the features of earth dams. And the following achievements at the first stage were made:1,This article stated the categories of uncertainties, the main uncertain factors and the features in the project, the calculation and evaluation method of the uncertainty and presented the blind information and blind number theory, building up the theory basis for the application of blind number in the evaluation of safety and durability.2,This article collected the data of dam breach at home and abroad, analyzed the reason of dam breach in detail and carried out the survey of disease type and existing condition based on the earth dams in Shan Dong Province. Realizing the rule and features of dam breach and having a common knowledge of the aging state of earth dams and the disease types, it provided basic materials for the construction of earth dams safety and durability evaluation system which complies with the features of reservoirs in Shan Dong Province.3,This article proposed the evaluation method which takes the durability of the earth dams as the evaluation standard. Basing on the analytic hierarchy process and taking the progressive aging condition and process as the rule, this method sets up the relationship between the aging coefficient and durability, establishes evaluation index system of earth dams and the evaluation method of index and carried out the quantification and objectification and reduced the personal subjective behavior, and the results are scientific, reasonable and comparable. This method analyzed objectively the existing and the future conditions of the dams and provided durability evaluation value for the cross comparing of the project and the open of a new method for the quality evaluation.4,This article analyzed systematically various calculation method and features of the evaluation of the stability of the dam slope, and proposed to apply circular slide method based on finite element stress analysis to the analysis of the stability of the dam slope, according to the extinction of pore water pressure in the rapid drawdown of the reservoir and the impact that the unsaturated soil has on the shearing strength of the soil. This method reflects the real force state of the slide surface. It is easy to set up reliability function according to antiskid system. It is easier to carry out the evaluation and analysis of the stability of the dam slope by combining the definite analysis with the reliability analysis of the stability of the earth dam side slope.5,This article analyzed the influencing factor and measuring method of the matrix suction and built up the method of using BP nerve network to find the angle of internal friction with respect to the matrix suction; applied blind number theory to reorganize and analyze the test data of shearing strength, then, rich test data can be provided and the lost of data caused by the previous statistical method can be avoided, providing basic data for the reliability analysis of the stability of the side slope.6,This article evaluated and analyzed the seepage stability of the earth dam with blind number theory, not only the safety degree of the seepage stability was clear, but the reliability degree of the evaluation result can be known, avoiding the average judging result and making the conclusion have more referencing value. This article applied the judging method of the reliability theory seepage stability to the example of the projects, evaluated the possibility of piping of the dam foundation and soil flowing at dam toe and the reliability of the conclusion on the base of the inspecting materials and predicted the seepage stability of the high water level with two methods of inspecting material analysis and inversion calculation, providing scientific rules for the judgment of the seepage stability of the earth dams. Thus, we can say that blind number theory provided an available method for the uncertainty evaluation and analysis of the seepage stability of the earth dam.7,This article discussed in detail the research condition of the impervious methods at home and abroad based on the durability of the impervious methods and stated the muddy water silting bed impervious methods based on the muddy water theory. This article analyzed systematically the stability of the composition of the soil of the Yellow River, the soil content of the lower river, the law of the particle composition changing with the seasons and carried out room test to verify the impervious performance of the muddy water silting bed. It analyzed the change of leakage and saturation line of the reservoir dam with the muddy water with Percolation Theory and exercised in the project. It was proved that using silted bed which wad made by the diversion of the muddy water of Yellow River as the impervious method of the reservoir dam not only can meet the impervious demand of the earth dam but also the durability is good. The muddy water impervious method can be learned by the similar projects. Key Words:Earth dam;blind number;stability;durability;seepage failure;muddy water theory;reliability This research is supported by the National Natural Science Foundation of China (50879069) This work was supported by the ministry of water resources public sector research and special(2007SHZ1-200701004) This research is supported by the National Natural Science Foundation of China (50679073) This research is supported by the National Natural Science Foundation of China (90510017)...