基于非一致融雪洪水的水库漫坝模糊风险分析

Fuzzy risk analysis of dam overtopping under inconsistent snowmelt floods

采用Pettitt非参数检验法和Mann-Kendall非参数趋势检验法分析肯斯瓦特水库入库年最大洪峰流量序列的非一致性,利用"分解-合成"理论对其进行了一致性修正,并通过基于直角梯形模糊数的风险分析法给出过去、现状两种条件下的水库漫坝模糊风险率。研究结果表明,年最大洪峰流量序列的变异点发生在1993年,序列整体上升变化趋势不显著,跳跃变异为其主要变异形式;在现状条件下不同截集水平α所对应的水库漫坝风险率区间上限估计值均较过去条件下的估计值要大,表明现状条件下融雪洪水受流域气温显著上升的影响,增大了水库漫坝失事的风险。结果可为有效利用汛期洪水资源、提高水库防洪效益、保障下游防护区的安全提供科学依据。

This study uses Pettitt test and Mann-Kendall test to analyze the inconsistency in the sequence of annual peak flood into the Ken Swart reservoir, conducts consistency correction by the decompositionsynthesis theory, and calculates the fuzzy risk rates of dam overtopping under the conditions of the past and present conditions through risk analysis using the method of the right-angled trapezoidal fuzzy numbers. Results show that in this sequence, a change point occurred in 1993, jumping is its major form of variation, and its overall increasing trend is insignificant. In the present condition, the upper limit estimates of the risk rates at different significant level α are larger than those in the past condition, indicating that the snowmelt floods, affected by the significant increase in temperature over the basin, raise the risk of reservoir failure. The results would help the efficient utilization of flood water resources increasing of flood control benefit, and security of downstream flood protection area.