Realistic modelling of transverse (i.e. vertical and lateral) pipe–soil interaction plays an important role in predicting the behaviour of untrenched offshore pipelines that are designed to undergo controlled lateral buckling. The large plastic soil deformations and surface geometry changes that occur during this process mean that numerical analyses using the continuum-based finite-element method are difficult and computationally expensive. Furthermore, most previous research in this area has focused on undrained deformation of soft clay seabed soils. This paper uses the three-dimensional distinct-element method (DEM) to investigate the behaviour of a pipe segment that is partially embedded in sand. The simulation approach is validated against experimental results for a monotonic vertical penetration test, a monotonic sideswipe test, and a cyclic lateral loading test performed under constant vertical load. Other DEM analyses are performed to illustrate the growth, deposition and collection of soil berms, and to investigate the effect of varying the initial vertical overloading ratio and the pipe weight. The DEM simulations provide quantitative predictions of the vertical and horizontal forces acting on the pipe segment, and of the pipe displacement trajectory. Valuable qualitative insights into soil failure mechanisms occurring at a grain level are also obtained.

中文翻译：

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砂土上横向管-土相互作用的DEM模拟

横向（即垂直和横向）管-土相互作用的逼真建模在预测设计用于受控的横向屈曲的未开挖海上管道的行为时，扮演着重要角色。在此过程中发生的大塑性土变形和表面几何形状变化意味着，使用基于连续谱的有限元方法进行数值分析非常困难，而且计算量很大。此外，该领域以前的大多数研究都集中在软粘土海底土壤的不排水变形上。本文使用三维离散元方法（DEM）来研究部分埋在沙子中的管段的行为。针对单调垂直渗透测试，单调侧擦测试，以及在恒定垂直载荷下进行的循环横向载荷测试。进行了其他DEM分析，以说明土壤护堤的生长，沉积和收集，并研究改变初始垂直超载比和管道重量的影响。DEM仿真提供了作用在管段上的垂直和水平力以及管位移轨迹的定量预测。还获得了对发生在谷物水平的土壤破坏机理的宝贵定性见解。DEM仿真提供了作用在管段上的垂直和水平力以及管位移轨迹的定量预测。还获得了对发生在谷物水平的土壤破坏机理的宝贵定性见解。DEM仿真提供了作用在管段上的垂直和水平力以及管位移轨迹的定量预测。还获得了对发生在谷物水平的土壤破坏机理的宝贵定性见解。