Abstract With the increasing development and utilization of offshore oil and gas resources, seabed instability around pipelines subjected to combined ocean wave and current loadings and protection of the pipelines are becoming increasingly important. As a general practice, it is recommended to use trenching in shallow water region for the protection of submarine pipelines from the danger caused by storm waves and ocean currents changing level of the seabed. For a better understanding of the physical process involved in wave–current–seabed–pipeline interactions (WCSPI), a workable Finite Volume Model (FVM) is proposed to simulate wave–current induced soil responses around offshore pipelines. Based on the established FVM model, this study investigates the momentary soil liquefaction induced by various environmental loadings in ocean environments. In the present model, data exchange is taken place on the seabed surface to couple the flow and seabed sub-models. Unlike most previous studies, ocean currents are included in the present model, in which the Volume-Averaged Reynolds-Averaged Navier–Stokes (VARANS) equation is employed to govern non-linear fluid motions, while Biot’s consolidation equation is used to link solid-pore fluid interactions in porous mediums. Numerical examples demonstrate the significant influence of ocean currents, trench geometry, and self-weight of the pipe on the wave-induced pore pressures and on the resultant seabed liquefaction around the pipeline.

中文翻译：

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联合波流诱导埋地管道周围的海床液化：沟槽层的设计

摘要 随着海洋油气资源开发利用的不断增加，海浪和海流联合作用下管道周围海床失稳及管道保护变得越来越重要。作为一般做法，建议在浅水区使用挖沟，以保护海底管道免受风暴浪和海流改变海床水位带来的危险。为了更好地理解波浪-流-海床-管道相互作用（WCSPI）中涉及的物理过程，提出了一种可行的有限体积模型（FVM）来模拟海上管道周围的波浪-流引起的土壤响应。本研究基于已建立的 FVM 模型，研究了海洋环境中各种环境载荷引起的瞬时土壤液化。在本模型中，数据交换发生在海床表面以耦合流动和海床子模型。与以前的大多数研究不同，本模型中包含洋流，其中体积平均雷诺数平均纳维 - 斯托克斯 (VARANS) 方程用于控制非线性流体运动，而 Biot 固结方程用于连接固体-多孔介质中的孔隙流体相互作用。数值例子证明了洋流、海沟几何形状和管道自重对波浪引起的孔隙压力和管道周围由此产生的海床液化的显着影响。其中体积平均雷诺数平均纳维-斯托克斯 (VARANS) 方程用于控制非线性流体运动，而 Biot 固结方程用于连接多孔介质中的固-孔流体相互作用。数值例子证明了洋流、海沟几何形状和管道自重对波浪引起的孔隙压力和管道周围由此产生的海床液化的显着影响。其中体积平均雷诺数平均纳维-斯托克斯 (VARANS) 方程用于控制非线性流体运动，而 Biot 固结方程用于连接多孔介质中的固-孔流体相互作用。数值例子证明了洋流、海沟几何形状和管道自重对波浪引起的孔隙压力和管道周围由此产生的海床液化的显着影响。