【作者】 黄海燕；

【导师】 麻荣永；

【作者基本信息】 广西大学 ， 水工结构工程， 2003， 硕士

【摘要】 本文详细介绍了风险分析的基本概念、理论与计算方法。针对传统的风险分析只考虑不确定性中的随机性，而不确定性中还包含有模糊性，提出应进行模糊风险分析，充分考虑随机性和模糊性。从而运用风险分析理论与相关的模糊数学知识建立了模糊风险的三种计算模型，并提出采用α水平截集将模糊变量模糊化处理为非模糊量计算模糊风险的求解方法。 鉴于我国土坝数量多，失事比重大，而漫坝与坝体失稳又是土坝失事的两个最主要因素，本文重点研究了土坝漫坝模糊风险与坝体失稳模糊风险的计算，在综合分析了影响漫坝及坝体失稳各种因素随机性和模糊性的基础上，建立了土坝漫坝模糊风险与坝体失稳模糊风险模型。针对两个数学模型难以用解析法求解的情况，采用离散化数值求解方法进行。编制了电算程序，具体对澄碧河水库进行漫坝模糊风险和坝体失稳模糊风险计算。 计算结果表明：对大坝进行模糊风险分析是可行的，考虑了模糊性的模糊风险为区间值，该区间值较传统的风险确定值更为合理，更符合工程实际。由于目前尚无大坝失事模糊风险标准，本文按未考虑模糊性的风险标准进行安全评价。更多还原

【Abstract】 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, three calculation models of fuzzy risk are 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 overtopping and instability are the two main causes to dam failure, this paper puts emphasis on the calculation of earth dam overtopping and instability fuzzy risk. After having analyzed the fuzziness and randomness of all factors, the overtopping and instability fuzzy risk models of earth dam are established. The paper approaches the inapplicability of analysis method to the two above-mentioned mathematical models by using dispersed demoted numerical virtue method. Programs are worked out and used for calculating overtopping and instability fuzzy risk of the Cheng Bi He Reservoir.The result shows that it is practicable to analyze the fuzzy risk of earth dam. With fuzziness considered, risk falls into circumscription category, and it is more reasonable and in more accordance with actual engineering compared with the traditional risk determinative value. 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.更多还原