考虑上游溃坝洪水的水库漫坝失事模糊风险分析

随着大江大河的规模化梯级开发,水库和电站的风险不再是单一工程风险,传统的"单库、定值"研究模式已难以满足当今水电站枢纽的安全风险分析需求。为此,本文将上游溃坝洪水的作用考虑到水库漫坝失事风险分析中,在具体评估水库承担的失事风险率时,基于现有的模糊风险分析模型尝试采用直角梯形模糊数描述水库漫坝失事的风险指标,结合α-截集技术将模糊集合转化为经典集合,提出基于直角梯形模糊数的水库漫坝失事风险分析模型。以某流域尚在筹建的水库为例进行研究,结果表明:(1)该模型能考虑多种不确定性因素影响的漫坝失事风险的可能状况,思路更接近于实际情况,其计算结果可为有关部门决策提供更多参考信息;(2)就研究对象而言,尽管考虑上游溃坝洪水时较高起调水位方案对应的漫坝失事模糊风险率均不同程度超出最大可接受风险,但只要做好预警工作并及时预泄水库蓄水就可以降低外部原因引起的漫坝失事风险,保障水库安全运行。

Analysis of the dam overtopping failure fuzzy risk under consideration of the upstream dam-break flood

In this study a dam overtopping failure fuzzy risk is described under consideration of the up-stream dam-break flood and a new risk model is presented to evaluate its failure fuzzy risk probability. Un-like other techniques previously proposed in the literature, the suggested approach is used the trapezoidal fuzzy number to show the complicated relationship between the fuzzy interval of risk indicator and failure probability and an uncompleted reservoir is taken as a case study. The results indicate that (1)the analysis model based on trapezoidal fuzzy number can describe the uncertainty of the complicated risk analysis sys-tem efficiently and accurately;(2)although the failure risk probability for the dam overtopping under consid-eration of the upstream dam-break flood is higher than the acceptable maximum probability at high water levels, establishing systems for early warning and lowering the water level can significantly reduce the risk and ensure the reservoir''s safety operation.