Abstract:Under the action of faults, the failure of pipelines with corrosion defects mainly occurs in weak parts of pipeline structure, such as corrosion areas. To explore the impact of corrosion-defect pipelines on the failure mode during fault displacement, a three-dimensional model of corrosion-defect pipelines crossing a reverse fault was established based on elastic-plastic finite element theory. On this basis, parameters such as corrosion position, corrosion depth, and fault dislocation were explored regarding their influence on local corrosion areas, pipe stress-strain distribution, and failure modes under the action of the reverse fault. The results showed that the main failure mode of the pipeline during fault displacement was local buckling damage at the top of the downthrown segment and the bottom of the upheld segment, with the bottom of the downthrown segment and the top of the upheld segment in tension. When the top of the upheld pipe segment was locally corroded, the main failure mode of the pipeline was a dual failure mode of tensile failure at the top of the upheld segment and local buckling failure at the bottom. When the top of the downthrown pipe segment was locally corroded, the main failure mode remained buckling failure, but the pipeline experienced buckling failure at a smaller fault dislocation. Different corrosion locations significantly affected the stress distribution of the corroded pipeline. Corrosion at the top of the downthrown pipe segment had a greater impact on the degradation of the pipeline's seismic performance compared to corrosion at the top of the upheld pipe segment, which in turn influenced the changes in the failure mode of the upheld pipe segment. As corrosion deepened, the strain caused by local corrosion at the top of the upheld pipe segment followed a nearly linear growth trend, while the strain caused by corrosion at the bottom of the downthrown pipe segment followed a nonlinear growth trend.