# Stochastic Mechanical Response and Failure Mode Transition of Corroded Buried Pipelines Subjected to Reverse Faulting

## TL;DR

This study explores how corrosion and pressure affect the failure of buried pipelines during geological faults, revealing new insights into failure modes and reliability.

## Contribution

A probabilistic framework integrating random field theory and a generative model to assess corroded pipelines under faulting is introduced.

## Key findings

- Internal pressure induces geometric stiffening, shifting failure modes from tensile rupture to ductile buckling.
- Spatial dispersion of pitting, not just average wall thinning, governs premature pipeline failure.
- High internal pressure increases tensile strain localization at corrosion pits, raising rupture risk under minor faults.

## Abstract

Buried oil and gas pipelines, the critical arteries of global energy infrastructure, are increasingly vulnerable to severe geological hazards such as reverse faulting, yet their structural integrity is often pre-compromised by stochastic corrosion damage accumulated during service. However, quantifying the coupled impact of spatial corrosion heterogeneity and large ground deformation remains a formidable challenge due to the complex nonlinearities involved in soil–structure interactions and wall thinning. This study establishes a probabilistic assessment framework integrating random field theory, nonlinear finite element analysis, and a generative conditional diffusion model to characterize realistic 2D non-Gaussian corrosion morphologies. The numerical results reveal a significant geometric stiffening effect induced by internal pressure, where moderate operating levels effectively suppress cross-sectional distortion by counteracting the Brazier effect. Consequently, this mechanism facilitates a fundamental transition in failure modes from localized tensile rupture to ductile buckling, significantly extending the critical fault displacement threshold. Furthermore, probabilistic fragility analysis demonstrates that the spatial dispersion of pitting, rather than just average wall thinning, governs the initiation of premature failure. Mechanistic analysis indicates that high internal pressure, while providing pneumatic support, exacerbates tensile strain localization at corrosion pits, leading to a heightened probability of premature rupture under minor fault deformations, a critical hazard that traditional deterministic models significantly underestimate. These findings provide a quantitative theoretical foundation for the reliability-based design and maintenance of energy lifelines traversing active tectonic zones.