针对水电工程风险因子的时变特性,用随机过程的方法模拟结构抗力与荷载作用,分析水电工程结构特性与运行方式,综合运用改进层次分析法、时变可靠度理论和风险率阈值,建立水电工程运行安全风险率评估模型.以土石坝工程为算例,详细展示时变风险率评估方法的分析流程.算例表明,工程运行安全风险率与服役时间及设计标准有着密切关系；考虑时变效应,风险率随时间推移而逐渐增大,其与设计标准的交点反映结构技术性使用寿命.应用文章提出的评估模型,预测运行期风险率变化趋势,可为水电工程的安全运行和风险决策提供科学依据.%In order to consider the time-dependent characteristic of risk factors of hydropower project, the method of stochastic process simulating structure resistance and load effect is adopted. On the basis of analyzing the structure characteristics and mode of operation, the operation safety risk rate assessment model of hydropower project is established on the comprehensive application of the improved analytic hierarchy process, the time-dependent reliability theory and the risk rate threshold. A scheme to demonstrate the time-dependent risk rate assessment method for an example of the earth-rock dam is particularly implemented by the proposed approach. The example shows that operation safety risk rate is closely related to both the service period and design standard; considering the effect of time-dependent, the risk rate increases with time and the intersection of them reflects the technical service life of structures. It could provide scientific basis for the operation safety and risk decision of the hydropower project by predicting the trend of risk rate via this model.
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