Analytical models of high-temperature pipeline deformation under submarine landslides

Abstract

Subsea pipelines may traverse areas prone to submarine landslides due to their long-distance transportation characteristics. As a common marine geohazard, submarine landslides pose a significant threat to the safety of pipelines. Pipelines can undergo lateral deformation over a certain length due to landslide impact, with the deformation constrained by axial and lateral pipe-soil resistances. This study constructs an analytical solution for the deformation of high-temperature subsea pipelines under landslide impact based on the Euler-Bernoulli beam theory, considering the nonlinear characteristics of axial soil resistance. The analytical solution is verified first. Then, the difference in various pipeline parameters between models considering ideal rigid-plastic and bi-linear axial resistance is compared. A parametric analysis is conducted by focusing on landslide impact force, landslide impact width, and seabed inclination angle. The results indicate that considering bi-linear axial resistance increases pipeline deformation. Larger landslide impact force, landslide impact width, and inclination angle result in greater pipeline deformation. At lower temperatures, both the bending moment and bending stress at the midpoint increase with landslide impact force and inclination angle, but they first increase and then decrease with landslide impact width. At higher temperatures, they decrease with the increase of landslide impact force, landslide impact width, and inclination angle. However, the tensile stress in the pipeline, induced by the axial force, continuously increases linearly with the increase in landslide impact force and landslide impact width.