非线性波浪荷载作用下裸置管道波浪力计算

Calculation of wave forces acting on unburied pipeline under nonlinear waves

为保证海底管道长期运行的稳定性,管道设计过程中需要充分考虑由非线性波浪荷载引起的波浪力。考虑海床土和孔隙水的压缩变形,基于非线性波浪理论,采用Biot固结方程,推导了非线性波浪荷载作用下裸置管道单位长度上的竖向作用力解析解,并结合埕岛油田不同海区50年一遇的波浪条件,计算不同尺寸的管道在各海区的波浪力极值。计算结果表明,在波浪条件相同的情况下,由于不同区域海床土的性质不同,所得到的极限波浪力有差别,因此在研究中不能忽视孔隙水的压缩和土骨架的变形。并将计算结果与采用有限元法计算该油田不同海区管道所受波浪力的情况进行对比,显示两种计算方法得到的结果相近,趋势相同。此成果在冀东滩海海底管道稳定性分析中得到了初步应用,实践表明给出的解析公式有一定的工程应用价值。

In order to ensure long-term operation stability of pipelines, the wave forces induced by nonlinear waves should be fully taken into account during the design process of pipelines. Considering the compressive deformation of seabed soil and pore water, the analytic solution of vertical force per unit length acting on unburied pipeline under nonlinear waves is deduced by using the Blot＇s consolidation equation based on the theory of nonlinear waves. Combined with 50 year return wave condition in different areas of Chengdao Oilfield, the maximum wave forces on pipelines with different size are cal- culated and the results are different due to the different seabed soil properties, so the effect of pore water compression and soil frame compression cannot be neglected in the study. The result is also compared with that from finite element analysis and shows that under the same wave condition there is little difference between them and they exhibit the same trend. The proposed analytic equation is valuble in engineering practice.