Guanyinyan hydroelectric station as a main point which links up as the Yangtze River middle reaches and the downstream water, will construct on the bedded rocks body which soft and hard rock alternate with, also the layers are multitudinous, gage distortion,has not constructed the high concrete dam in the domestic and foreign hydroelectric station construction on this kind of dam base before.

Herein, the coupling method of deformable distinct elements with two nonlinear fracture mechanics models-smeared and discrete crack models is presented and applied to analyze the fracture and collapse of high concrete dam. The main contents are summarized as below:

Through finite element calculation,the paper analyses and evaluates the conditions of stabili-ty,stress and deformation for building a high concrete dam on low elastic modulus rock strata ofGuxian dam foundation. It also discusses the issues of deep slide,friction coefficient and control-ling index for allowable displacement.

This article embarks from the dam foundation rock project characteristic, constructed the high concrete dam to the Guanyinyanyan foundation rock to be suitable the nature to conduct the research.

On the basis of comprehensive analysis on flood release and energy dissipation design experiences of high concrete dam at home and abroad the design principles and energy dissipation methods for ? ? flood release of high concrete dam are discussed.

Further, attention should be paid to the research on the failure modes and criterions of high concrete dam failure analysis and safety evaluation, and the effect of uncertainty and classification of safety should be considered too.

This paper involves the main contents and mechanical features of the safety analysis on high concrete dam and shows the current state and progress of the analysis methods.

Without any exiting specification or successful experiences of concrete dams up to 300 m at home and abroad for reference, experts feel obliged to figure out how to perform safety analysis on high concrete dam.

Research advance in safety analysis methods for high concrete dam

For the fact that the growing number of high concrete dams built in valley, the promblems existing in the dissipation of flow energy become more and more significant. Mechanism of energy dissipation of diffusion by sky-jump is discussed in this paper by means of turbulence theory and test. From the discussion such a conclusion can be arrived at that the essential of energy dissipation of diffusion are actions due to turbulence and due to entrained air. In addition, ways in which the effect of energy dissipation...

For the fact that the growing number of high concrete dams built in valley, the promblems existing in the dissipation of flow energy become more and more significant. Mechanism of energy dissipation of diffusion by sky-jump is discussed in this paper by means of turbulence theory and test. From the discussion such a conclusion can be arrived at that the essential of energy dissipation of diffusion are actions due to turbulence and due to entrained air. In addition, ways in which the effect of energy dissipation of diffusion can be improved are proposed.

Risk analysis for the hydraulic design of engineering project is a new problem for hydraulic engineers all over the world. A risk computation model is given in the paper. The major concern of the paper is to show how hydrologic and hydraulic uncertainties can be analysed and how flood relief risk of high concrete dams can be computed. The JC method used widely in structural risk computation is introduced into hydraulic risk computation, which is more convennient and practical than other methods which is...

Risk analysis for the hydraulic design of engineering project is a new problem for hydraulic engineers all over the world. A risk computation model is given in the paper. The major concern of the paper is to show how hydrologic and hydraulic uncertainties can be analysed and how flood relief risk of high concrete dams can be computed. The JC method used widely in structural risk computation is introduced into hydraulic risk computation, which is more convennient and practical than other methods which is now being used in hydraulic risk computation. In order to illustrate flood relief risk computation for high concrete dams, some large hydro-power projects are taken as examples. The results show that, the flood relief risk value of high concrete dams in our country is about 10~(-5), it coincides with results by other researchers abroad. The computing method and results provide reference for safety inspection and design of high concrete dams.

The tests on concrete fracture were carried out by using huge compact tension specimens with maximum dimensions 3.6×3.0×0.2m. Itwas found that the measured values of fracture toughness K_(IC) of concrete are independent of the sizes of the specimens when the height of the specimens are larger than 2m. Therefore, linear elastic fracture mechanics can be applied to stability analyses of cracks in mass concrete structures and to improving design methods of hydraulic structures. The results obtained...

The tests on concrete fracture were carried out by using huge compact tension specimens with maximum dimensions 3.6×3.0×0.2m. Itwas found that the measured values of fracture toughness K_(IC) of concrete are independent of the sizes of the specimens when the height of the specimens are larger than 2m. Therefore, linear elastic fracture mechanics can be applied to stability analyses of cracks in mass concrete structures and to improving design methods of hydraulic structures. The results obtained show that the parameter of fracture toughness of concrete K_(IC) can be taken as a fracture criterion for judging the stability of cracks in mass concrete structures, such as the high concrete dams.