Research on Damage Assessment of Buried Polyurea-Reinforced Petroleum Pipelines with Localized Defects Subjected to Blast Loading in Soil

Buried petroleum pipelines with localized defects are vulnerable to blast loading, and an effective damage assessment method for polyurea-reinforced defective pipelines is still lacking. In this study, full-scale blast tests and numerical simulations were combined to investigate the dynamic response and damage characteristics of standard and polyurea-reinforced N80 buried pipelines with localized defects under shallow-buried blast loading. The experimental results showed that, at a scaled distance of 0.23 m/kg1/3, polyurea reinforcement reduced the maximum dent depth from 69 mm to 63 mm, corresponding to a reduction of 8.69%, and decreased the peak overpressure on the blast-facing surface by 23.0% compared with the unreinforced pipeline. Based on the critical dent depth-to-length ratio of 0.072, a pressure–impulse (P–I) damage evaluation curve and its fitted equation were established for engineering assessment. The proposed method establishes a preliminary framework for evaluating blast-induced damage in buried polyurea-reinforced petroleum pipelines with localized defects under the specific tested conditions and provides a preliminary framework and a basis for future research, while its general applicability remains to be further validated. Therefore, this work is explicitly designated as a pilot study that offers initial insights under the tested conditions, and further research is needed to validate its broader applicability.