海洋立管的局部冲刷实验

Physical model test for local scour around marine riser

海洋平台立管底部的局部冲刷容易造成海底管道的暴露悬空,在波浪和水流作用下产生疲劳破坏,以往的研究多偏重于海底管道水平段局部冲刷,而对立管底部开始的局部冲刷研究较少.针对这些问题,通过实验室物理模型实验,利用波流水槽对波-流共存以及纯波浪条件下海洋平台立管-桩系统基础周围的局部冲刷进行了研究.通过实验观测立管系统周围海底地形的冲淤变化过程,得到冲刷稳定后的地形形态、各冲深监测点的冲深历时曲线及最大冲刷深度.通过对实测数据的分析,探讨了水深、波高、恒定来流流速、立管-桩系统倾斜角度以及床面泥沙粒径等参数对冲刷形态和最大冲刷深度的影响.

The local scour at the bottom of marine riser is easy to result in the exposure and suspension of seabed pipeline, and thus the fatigue damage of the pipeline occurs due to the action of wave and flow. The previous researches concerning the local scour problem of seabed pipeline mainly focus on the scour around a horizontal span rather than that at riser bottom. Thus, the physical model tests utilizing wave-flow flume were conducted to investigate the local scour around a riser-pile system in both coexistng wave-flow and pure wave conditions. The change process in the sea bottom terrain around the riser system was observed. The scoured terrain of the sea bottom as well as the scour depth-time curve and maximum scour depth at different inspection points were recorded. Based on the meassured data, the influnce of such parameters as water depth, wave height, flow velocity, incline angle of riser-pile system and particle size of sediment on the scour pattern and maximum scour depth were discussed.