Laboratory-Based Fatigue Investigation of Buried Natural Gas Pipelines under Train-Induced Vibrations

Abstract

This study investigated the fatigue susceptibility of buried gas pipelines under train-induced vibrations, excluding joint behavior and corrosion effects. It assessed material fatigue response and casing mitigation efficacy. Owing to restricted field access, a scaled pipeline network was instrumented and excited with a plate compactor reproducing train vibrations with dominant frequencies of 30–40 Hz. Pipeline ovalization induced by passing trains—the primary stress source—was derived from double-integrated accelerations. Fatigue life was estimated using rainflow counting and Miner’s rule, and yielded peak equivalent stresses of 0.9–1.8 MPa and negligible fatigue damage fractions. Casings accelerated fatigue damage via vibration transmission at contact points. Numerical analyses indicated that stiffer, compacted backfill reduces susceptibility, whereas saturated soils and shallower burial depths increase it. Future work should address joint fatigue and explore alternative protection strategies for pipelines beneath railways or roads in fatigue-prone, high-traffic locations.