斜向波作用下海底管线周围床沙组成变化

海底管线周围的不平衡输沙影响着海底管线的局部冲刷，进而影响海底管线的安全运营。基于波浪港池实验，考虑规则波的作用，采用中值粒径为0.219 mm的原型沙铺设与波浪传播方向成45°夹角的斜坡，斜坡坡度为1∶15，研究管线局部冲刷坑床沙组成变化情况。实验结果表明:与冲刷深度随时间的发展类似，冲刷宽度随时间的发展也分为初级阶段和次级阶段；管线周围床沙粗化程度最高的地方并不在管线的正下方，而在管线的后下方；周期增加，冲刷坑床沙粗化程度增大；与原始床沙相比，周期较小时，冲刷坑下方床沙细化，周期较大时则粗化，而波高对床沙扰动的影响具有不稳定性。

Sorting of sand grains around submarine pipelines under the oblique wave

Non-equilibrium sediments transport near the submarine pipeline results in local scour, thus endangering the operation of the pipeline. To investigate the sorting of sand grains in local scour hole under regular wave action, an experimental study is performed in the wave basin. The 1:15 slope with prototype sand, the median diameter of which is 0.219 mm, is tested against waves coming at 45 degree. The experimental results indicate that the evolution of the scour width, as well as the scour depth, can be divided into two stages: the primary stage and the secondary stage. The highest degree of bed coarsening is found to occur behind the pipeline rather than under the pipeline; bed coarsening grows with the increase of wave period, that is, the sand in the scour hole, compared with initial sand bed, will be refined under action of the short-period wave and coarsened by the long-period wave. However, the relationship between the wave height and the perturbation of bed sediment is not significant.