Analysis Of Fuzzy Risk On Earth Dams

Our country is the big country of dam-maker. There is the most amount of the earth dam throughout the world, and the same to the cases of accidents, among them, the earth dam safety is especially serious. The dams are found everywhere and play an important role in our economy development. But the potential hazard is also huge; once dams' wrecks happen it will bring serious damage. Along with the old dams and the sick dams getting more and more, the dams' security causes people's high attention. Meanwhile the dams' risk analysis is outspread rapidly through the world.This paper introduces comprehensively the basic theory and calculation methods of risk analysis. In view of the absence of fuzziness analysis in the traditional risk analysis, fuzzy risk analysis, which, together with randomness, constitutes the two inseparable uncertainty elements, deserves exposition. Based on the theory of risk analysis and fuzzy mathematics, calculation model of fuzzy risk is established and solution is presented. This solution transforms fuzzy variables into random variables by level cut set so that fuzzy risk can be calculated with traditional risk calculation methods.In view of the great number of earth dams, the high proportion of dam failure in China, and seepage failure instability and overtopping are the three main modes to dam failure, this paper puts emphasis research on thereinafter several aspects.1 After having synthetically analyzed the fuzziness and randomness of all factors, the seepage failure instability and overtopping fuzzy risk models of earth dam are established.2 The paper approaches the inapplicability of analysis method to the three above-mentioned mathematical models by using dispersed demoted numerical virtue method with Monte-Carlo method. Programs by MATLAB are worked out and used for calculating risk probability.3 Seepage failure instability and overtopping fuzzy risk models are used in the Long Xing Si Reservoir. The result is accordance with the Dam Safety Identify in the literature[56]. So the models is reasonable and feasible, the arithmetic is accurate.With randomicity and fuzziness adequately considered in the dam risk analysis, risk falls into circumscription category, and it is more reasonable and in more accordance with actual engineering compared with the traditional risk determinative value. So It is practicable to analyze the fuzzy risk of earth dam. Because the fuzzy risk standard of dam failure has not been established, the traditional risk standard is used for the safety evaluation in this paper.