内压与海床联合作用下海底管道撞击数值研究

Numerical Study of Impact on Submarine Pipeline under the Joint Action of Seabed and Internal Pressure

为了研究海床和管道内压对坠物撞击管道的影响,采用ABAQUS有限元软件建立了坠物撞击海底管道的有限元模型,分析了撞击过程中海底管道的动态响应。采用摩尔库伦模型模拟海床的非线性特性,并引入罚函数处理坠物、管道和海床三者的接触关系。分析结果表明:海床和管道内压对坠物撞击管道起到了保护作用。黏土海床对管道撞击的保护作用比砂土海床大,砂土海床对管道撞击的保护作用比刚性海床大;随着内压的增大,管道变形最大凹陷值减小;同时考虑内压和海床作用时管道受坠物撞击后的最大凹陷值比2个因素均不考虑时小,相差最大处达到了9.6%。所得结果对海底管道抗坠物撞击设计和管道的安全服役具有指导意义。

In order to study the influence of seabed and internal pressure on the impact of falling object on the pipeline, a finite element model of the impact of falling object on the submarine pipeline is set u p by A B A Q U S soft -ware to analyze the dynamic response of submarine pipeline during impact. The Mohr-Coulomb model is used to simulate the nonlinear characteristics of the seabed. The penalty function is introduced to deal with the contact rela-tionship between the falling object, the pipeline and the seabed. The analysis results show that the seabed and the pipeline inner pressure play a protective role against the impact of falling object on the pipeline. The protective per-formance of clay seabed on pipeline impact is greater than that of sand seabed, which is larger than that of rigid seabed. With the increase of internal pressure, the m a x i m u m sag magnitude of pipeline decreases. The m a x i m u m sag magnitude of pipeline is smaller compared with that neglecting the effect of pipeline inner pressure and the sea-bed ,and the difference reaches 9. 6% at the m a x i m u m. The results could provide guidance for anti-impact design of submarine pipeline and pipeline safe service.