根据映射关系,将风险分析故障树(FT)模型转化成贝叶斯网络(BN)模型,并基于专家群体判断和模糊理论提出了具有多态性和模糊性基本事件的土石坝溃决贝叶斯网络风险概率计算方法,提升了体系风险计算方法的应用深度与广度。土石坝算例分析表明,采用本文方法可以得到溃坝事件的联合概率分布以及体系中各级事件的后验概率分布,并基于后验概率对具有多态与模糊性的基本事件进行重要度排序,以利于土石坝溃决风险评估与决策。本文方法对于工程失事风险分析方面的研究具有通用性,可为多层次、多因素、多状态复杂工程风险分析理论与方法研究提供借鉴和参考。
A fault tree (FT) model can be converted to a Bayesian network (BN) by mapping relationships. This paper describes a risk probability computing method using a Bayesian net work model that is based on the group judgment of experts and the fuzzy theory, and presents an application of the method to analysis on the risk of earth rock-fill dam break associated with multi-state and fuzzy basic events. A case study showed that this new method can calculate the joint probability distribution of a dam break event and the posterior probability of those events on every level of the system, and thus obtain an importance sequence of the multi-state and fuzzy basic events using the values of posterior probabilities calculated. It expands the application scope of system risk calculation methods to more in-depth analysis, very helpful not just for risk assessment of earth rock-fill dam breaks but for analysis of failure events in other engineering fields. Thus, this new approach would be a useful guide for examination of complex multiple level, multi-factor, multi-state problems.