Urban gas pipelines usually have high structural vulnerability due to long service time. The locations across urban areas with high population density make the gas pipelines easily exposed to external activities. Recently, urban pipelines may also have been the target of terrorist attacks. Nevertheless, the intentional damage, i.e. terrorist attack, was seldom considered in previous risk analysis of urban gas pipelines. This work presents a dynamic risk analysis of external activities to urban gas pipelines, which integrates unintentional and intentional damage to pipelines in a unified framework. A Bayesian network mapping from the Bow-tie model is used to represent the evolution process of pipeline accidents initiating from intentional and unintentional hazards. The probabilities of basic events and safety barriers are estimated by adopting the Fuzzy set theory and hierarchical Bayesian analysis (HBA). The developed model enables assessment of the dynamic probabilities of consequences and identifies the most credible contributing factors to the risk, given observed evidence. It also captures both data and model uncertainties. Eventually, an industrial case is presented to illustrate the applicability and effectiveness of the developed methodology. It is observed that the proposed methodology helps to more accurately conduct risk assessment and management of urban natural gas pipelines.

由于使用寿命长，城市燃气管道通常具有较高的结构脆弱性。人口密度高的城市地区的位置使天然气管道容易暴露于外部活动。最近，城市管道也可能成为恐怖袭击的目标。然而，在先前对城市燃气管道的风险分析中，很少考虑到故意破坏，即恐怖袭击。这项工作提供了对城市燃气管道外部活动的动态风险分析，该分析将对管道的无意和有意破坏整合到一个统一的框架中。使用Bow-tie模型的贝叶斯网络映射表示由故意和非故意危害引发的管道事故的演变过程。通过采用模糊集理论和层次贝叶斯分析（HBA）估算基本事件和安全障碍的可能性。所开发的模型能够评估后果的动态概率，并根据观察到的证据确定最可信的风险因素。它还捕获数据和模型不确定性。最后，提出了一个工业案例来说明所开发方法的适用性和有效性。可以看出，所提出的方法有助于更准确地进行城市天然气管道的风险评估和管理。提供观察到的证据。它还捕获数据和模型不确定性。最后，提出了一个工业案例来说明所开发方法的适用性和有效性。可以看出，所提出的方法有助于更准确地进行城市天然气管道的风险评估和管理。提供观察到的证据。它还捕获数据和模型不确定性。最后，提出了一个工业案例来说明所开发方法的适用性和有效性。可以看出，所提出的方法有助于更准确地进行城市天然气管道的风险评估和管理。