考虑管土作用悬跨管道纯顺流向涡激振动研究

摘要

To reveal the dynamic features of a free⁃spanning pipeline undergoing pure in⁃line ( IL) vortex⁃induced vibrations ( VIVs) on the seabed, in this paper, we consider the pipeline⁃soil interaction at the shoulders. In com⁃bination with the Euler⁃Bernoulli beam theory and the Van der Pol equation, we propose a pure IL VIV prediction model for a free⁃spanning pipeline on the seabed. We studied the influences of the undrained shear strength at the mudline, the strength gradient, the pipeline embedding depth in the soil at the shoulders, and the plasticity index in pure IL VIVs in a spanning pipeline. We found that pure IL VIVs are more easily excited in the presence of wea⁃ker undrained shear strength at the mudline, a smaller strength gradient, shallower pipeline embedment, and a lar⁃ger plasticity index.%为了揭示海底自由悬跨管道纯顺流向涡激振动特征，本文考虑跨肩处管－土耦合作用，结合Euler⁃Bernoulli梁理论和Van der pol方程，构建了海底自由悬跨管道纯顺流向涡激振动的预报模型，分析了海底泥面土体不排水抗剪强度、土体强度梯度、跨肩处管道嵌入土体深度和土体塑性指数等对纯顺流向涡激振动的影响规律。研究结果表明：泥面土体不排水抗剪强度越弱、土体强度梯度越小、管道嵌入土体越浅、塑性指数越大，纯顺流向涡激振动越容易发生。