考虑海床变形的裸露悬跨海底管道静力分析

Static analysis of unburied spanning submarine pipeline on linear elastic seabed

针对裸露悬跨海底管道,考虑线弹性海床刚度,利用梁的小挠度理论,研究管道在自重作用下的变形和内力,推导给出了未脱离海床的管道段和悬跨管道段的变形和内力公式。在跨度较大的悬跨情况下,悬跨管道段较大的向下弯曲变形可能引起海床上管道脱离海床而翘起。建立管道翘起的判定准则,对于翘起情况推导相应的计算公式,通过算例给出翘起情况下管道的变形和内力。通过计算分析发现:工程上多数悬跨是翘起情况,没有翘起的计算公式只适应于跨度较小的悬跨管道。同时翘起情况下不同海床刚度对悬跨管道无量纲内力影响不大。

With small deflection beam theory,the deformation and internal forces of the unburied spanning submarine pipe on linear elastic seabed under self-weight load are studied,and deformation and internal forces formulae of the un-separated section and spanning section are reduced.The touched section on seabed may leave seabed and rise upward while the spanning section bends down for large spanning pipelines.Determination criterion and its corresponding formula for the rise-upward case are built,and examples are given to illustrate the deformation and internal forces calculation.Calculation examples show that most of the spanning in engineering is the rise upward one,and the formula for the touched case is only valid for small spanning pipelines.Meanwhile,different stiffness of seabed has little effects on non-dimensional internal forces of the spanning pipe in the rise upward case.