Draper Scott, An Hongwei, Cheng Liang, White David J, Griffiths Terry
Centre for Offshore Foundation Systems, 35 Stirling Hwy, Crawley, Perth, WA 6009, Australia School of Civil, Environmental and Mining Engineering, 35 Stirling Hwy, Crawley, Perth, WA 6009, Australia
School of Civil, Environmental and Mining Engineering, 35 Stirling Hwy, Crawley, Perth, WA 6009, Australia.
Philos Trans A Math Phys Eng Sci. 2015 Jan 28;373(2033). doi: 10.1098/rsta.2014.0106.
On-bottom stability design of subsea pipelines transporting hydrocarbons is important to ensure safety and reliability but is challenging to achieve in the onerous metocean (meteorological and oceanographic) conditions typical of large storms (such as tropical cyclones, hurricanes or typhoons). This challenge is increased by the fact that industry design guidelines presently give no guidance on how to incorporate the potential benefits of seabed mobility, which can lead to lowering and self-burial of the pipeline on a sandy seabed. In this paper, we demonstrate recent advances in experimental modelling of pipeline scour and present results investigating how pipeline stability can change in a large storm. An emphasis is placed on the initial development of the storm, where scour is inevitable on an erodible bed as the storm velocities build up to peak conditions. During this initial development, we compare the rate at which peak near-bed velocities increase in a large storm (typically less than 10(-3) m s(-2)) to the rate at which a pipeline scours and subsequently lowers (which is dependent not only on the storm velocities, but also on the mechanism of lowering and the pipeline properties). We show that the relative magnitude of these rates influences pipeline embedment during a storm and the stability of the pipeline.
输送碳氢化合物的海底管道的海底稳定性设计对于确保安全和可靠性至关重要，但在大型风暴（如热带气旋、飓风或台风）典型的恶劣海洋气象（气象和海洋学）条件下实现这一目标具有挑战性。目前行业设计指南未就如何纳入海底可移动性的潜在益处提供指导，这一事实加剧了这一挑战，海底可移动性可能导致管道在沙质海床上下沉并自行掩埋。在本文中，我们展示了管道冲刷实验建模的最新进展，并给出了研究大型风暴中管道稳定性如何变化的结果。重点在于风暴的初始发展阶段，在此阶段，随着风暴速度增至峰值条件，在易侵蚀的海床上冲刷是不可避免的。在这个初始发展阶段，我们将大型风暴中近床峰值速度增加的速率（通常小于10(-3) 米每秒）与管道冲刷并随后下沉的速率（这不仅取决于风暴速度，还取决于下沉机制和管道特性）进行比较。我们表明，这些速率的相对大小会影响风暴期间管道的埋深以及管道的稳定性。
