Seismic Vulnerability Assessment Method of PE Gas Pipeline Networks Based on a Comprehensive Weight Cloud Model

Frequently occurring earthquakes can cause serious damage to lifeline engineering, which significantly affects residents’ living conditions. As an important part of the urban lifeline, predicting the seismic vulnerability of urban gas pipeline networks is crucial for reducing pipeline network damage. However, current research primarily focuses on the seismic vulnerability analysis of single pipelines, while the large size and complexity of urban gas pipeline networks limit overall seismic vulnerability research. The pipe material used for urban gas pipelines is primarily polyethylene (PE). In this study, an assessment index system for the seismic vulnerability of polyethylene gas pipeline networks is constructed. By combining the improved ordinal relationship (G1) method and the improved entropy weight method to calculate the weights, a comprehensive assessment of the seismic vulnerability of urban gas pipeline networks is realized using cloud modeling. Finally, this method is applied to the urban gas pipeline network of a city in China. The study results indicate that (1) the 18 indicators comprehensively cover the seismic impact factors of urban gas pipeline networks; (2) the effective combination of the improved G1 method and the improved entropy weighting method considers both the importance and magnitude of change of the indicators; (3) the cloud model can synthesize the stochasticity and uncertainty of earthquakes; and (4) a case study demonstrates that the method can assess the vulnerability of each pipeline in the target pipeline network, identify the most important seismic impact factors, and propose targeted seismic measures. In conclusion, the study methodology provides an effective tool for urban planners and decision makers to better assess and manage the seismic risk of natural gas pipelines.