Seismic Fragility Assessment and Influencing Factors of Buried Oil Pipelines

The seismic vulnerability of buried pipelines, affected by multiple factors with significant variations under different conditions, poses challenges for accurate assessment due to differing model applicability and complex multi-factor coupling effects. Using Incremental Dynamic Analysis (IDA), this study verified the accuracy of discrete spring and 3D solid models, then considered factors like soil type, burial depth, wall thickness, internal pressure, and corrosion age. Twenty suitable ground motion records were selected, with the peak ground acceleration ( PGA ) as the intensity measure (IM) and the maximum axial tensile strain as the damage measure (DM). A probabilistic seismic demand model was established, and the seismic response and vulnerability of buried oil pipelines were studied. Results show 3D solid models are more accurate; pipeline response and failure probability in soft soil are much higher than in hard soil; greater burial depth and wall thickness reduce seismic impact, while higher internal pressure and longer corrosion age weaken seismic performance. This study offers reference for seismic risk assessment and anti-seismic optimization design.