关键词: 海底管线, 水平向整体屈曲, 土体阻力模型, ABAQUS二次开发, 子程序VFRIC

Abstract: High temperature and high pressure can lead to a lateral global buckling of unburied or shallowly buried submarine pipelines. Because soil resistance determines the deformation and stress distribution of post-buckling pipelines, it is important to characterize the soil resistance in the pipeline global buckling analysis. A series of model tests based on the sand sampled from Bohai Gulf is conducted. The soil resistance to pipelines with different buried depths are measured. A dynamical soil resistance model varying with the buried depth of pipeline is developed, and the influence of buried depth on peak soil resistance and final soil resistance is analyzed. As the built-in penalty interaction model in ABAQUS software cannot simulate the dynamical friction in pipe-soil interaction, a user-defined subroutine VFRIC is developed to implement the established soil resistance model and used to simulate the variation of soil resistance with pipeline displacement for accurate pipeline global buckling analysis. The study shows that the soil resistance model can significantly affect the results of post-buckling pipeline. Because the dynamical soil resistance model has a peak value and an attenuation process, the critical buckling force of post-buckling pipelines with dynamical soil resistance model is larger than pipeline with constant soil resistance, the deformation of post-buckling pipelines with dynamical soil resistance model is more concentrated, and the maximum bending moment and strain are larger.

Key words: submarine pipeline, lateral global buckling, soil resistance model, the secondary development of ABAQUS software, user subroutine VFRIC