DYNAMIC RESPONSES AND SAFETY EVALUATION OF SUSPENDED PIPELINES IMPACTED BY SUBMARINE LANDSLIDES

Submarine landslides are a common type of marine geo-disasters and can cause huge threat to the safety of oil and gas pipelines. Due to scour effect of seabed currents, submarine pipelines are usually suspended above the seabed surface, leading to poor pipeline stability. When the suspended pipeline is impacted by the submarine landslide, prediction of pipeline dynamic responses and safety evaluation become especially important. In this study, a finite element model of submarine landslide-pipeline interaction is developed through dividing the pipeline into the suspended and burial sections. The model is capable of capturing dynamic responses of oil and gas pipelines subjected to submarine landslides considering different pipeline spanning lengths and heights. Numerical analyses show that the influence of spanning length and height on the plastic strain of the pipeline is conspicuous. The pipeline strain induced by submarine landslides increases with the increase of spanning length and height. Finally, combing the effect of spanning length and height, a safety evaluation method of suspended pipelines under the impact of submarine landslides is proposed. The results can be directly used for dynamic evaluation of oil and gas pipeline safety under the impact of submarine landslides.