【作者】 申志高；

【导师】 胡国华； 李桂元；

【作者基本信息】 长沙理工大学 ， 水力学及河流动力学， 2008， 硕士

【摘要】 大坝安全评价中常规的定值安全评价方法,由于没有考虑到设计变量的变异性,安全系数的大小并不能完全确切地表征工程的安全程度。本论文正是基于风险理论和灰色理论对上沙江水库大坝安全进行风险分析,通过较为合理的风险计算模型和风险分析方法定量地估算大坝几种主要的失事风险率,主要成果与结论如下:（1）研究分析了大坝溃坝模式的机理及成因,提出一种定性和定量相结合的确定大坝失事风险率的方法。并运用这种方法对上沙江水库大坝失事模式进行了风险识别,识别出该水库最可能失事的建筑物就是大坝。（2）基于灰色-随机风险理论建立了上沙江水库大坝坝坡失稳风险模型。以JC法为基础,编制Matlab电算程序计算了风险率,得到坝坡失稳的风险率区间[0.1285,0.1503],较好地体现和度量了风险率的不确定性,能比现行的可靠度方法提供更丰富的信息。如果按传统的条分法计算坝坡稳定安全系数,上沙江水库大坝安全系数K （1.152） > 1,表明大坝处于稳定状态。而考虑坝坡系统状态变量的分布和不确定性后,计算的坝坡有12.85%～15.03%的失稳滑动风险。反映了安全系数的大小并不能完全确切地表征大坝的安全程度。（3）基于灰色-随机风险理论建立了上沙江水库大坝漫顶风险模型,用JC法分别计算了设计洪水和校核洪水条件下的漫顶风险率:在现有大坝坝顶高程212.5m情况下,计算出大坝在设计洪水位和校核洪水位条件下漫顶的风险率都近似为0。当取坝顶高程为210.1m（与设计规范所要求的高程接近）,计算结果为:设计洪水情况下,大坝的漫顶风险率近似为0,校核洪水情况下,大坝的漫顶风险率为区间[9.5479×10^-9,2.0085×10^-5]。而我国20世纪80年代大坝的年均总体漫顶失事率为Pf =1.2710×^-4,表明设计规范所要求的安全超高使大坝具有较大的抗洪潜力。更多还原

【Abstract】 In the conventional method of setting safety factor assessment of dam ,the degree of safety can not be completely accurately characterized with the size of safety factor without taking into account the variability of design variables. Based on risk theory and the grey theory, this paper analyses dam risk of ShangShajiang Reservoir and adopts a more reasonable risk calculation model and risk analysis method to estimate several major dam accident risk probability, the main conclusion of the research are shown as following:（1） The mechanism and the causes of the hidden accident patterns of dam are analyzed and the possible hidden accident patterns are identified, the practical accident patterns are acquired by analyzing. The most likely failure building is the dam.（2）Based on the grey-stochastic risk theory, a risk model of slope failure of dam on the ShangShaJiang Reservoir is established. Based on the JC method, the grey-stochastic risk probability of slope failure can be calculated, the result is a risk interval [0.1285, 0.1503]. The grey-stochastic risk better reflects and measures the uncertainty of risk and it can offer more information than other reliability methods. For the stable evaluation of the dam slope discussed in this paper, the value of the safety factor, which is calculated by the traditional safety factor method, is 1.152. If K>1, that shows the dam slope is safe. However, considering the distribution of state variables and uncertainty of the dam slope system, the risk probability of the dam slope failure calculated by the grey-stochastic risk method still reach 12.85%～15.03%, so the degree of dam safety can not be completely accurately characterized with the size of safety factor.（3） Based on the grey-stochastic risk theory, a overtopping risk model of the ShangShaJiang Reservoir dam is established. The overtopping risk probability were calculated by using JC method in checking and designing flood level. If the height of the dam is 211.5m , the accident risk probability approximate zero. If in 210.5m （approximating the design specification height）and in design flood situation, the accident risk rate approximate zero, too. But in checking flood situation, the grey-stochastic accident risk probability is a interval [9.5479×10^-9,2.0085×10^-5].In the 1980s, the average annual overall accident probability of the dam is Pf =1.2710×^-4 in China. It is proved that the dam have greater potential to prevent flood and ultra-high security by the design specifications.更多还原