• Large-scale rockfall impact experiments on buried pipelines were conducted considering varying impact eccentricities. • The influence of different factors on pipe strain attenuation with impact eccentricity was explored using finite element modeling. • An equation describing the attenuation of pipe strain as a function of impact eccentricity was developed. For rockfall protection measures pertaining to buried oil and gas pipelines, such as embankments, flexible barriers, and cushions, a key issue is determining their reasonable protection range in a cost-effective manner. In other words, what is the threshold of impact eccentricity (the distance from the expected impact point to the pipeline) that necessitates the implementation of these protection measures? To address this question, we conducted a series of rockfall impact tests on a buried steel pipeline with varying eccentricities, revealing a clear power-law attenuation relationship between pipe crown strain and impact eccentricity. Several finite element models were established and verified to further investigate the correlation between the strain attenuation and several potential influencing factors. Then, a novel quantitative calculation method for the attenuation of pipe strain with impact eccentricity was proposed. The accuracy of this method was verified through field tests, laboratory tests, and numerical simulations. Through the relationship demonstrated by the pipe strain and the impact eccentricity, it is recommended that rockfall protection measures should focus on either preventing impacts within 2 meters of the pipeline or installing a cushioning layer (such as a sand cushion) in this area.
Yang et al. (Sun,) studied this question.