Modelling the embedment process during offshore pipe-laying on fine-grained soils
Modelling the embedment process during offshore pipe-laying on fine-grained soils
复制标题
DOI：
10.1139/cgj-2012-0185
复制
发表时间：
2013
影响因子：
3.6
通讯作者：
Z. Westgate;D. White;M. Randolph
中科院分区：
文献类型：
--
作者：
Z. Westgate;D. White;M. Randolph
随着油气勘探逐渐进入远离海岸的深水环境，海底管道正成为海上油气开发中越来越重要的组成部分。在铺设过程中，受海况和铺设船运动的影响，管道受到小幅度的垂直和水平振荡的影响。离心机模型试验已用于模拟这些小振幅铺层效应，相对于实际铺层过程具有不同程度的理想化。在深水软土中，管道埋置可以超过直径或更大，从而显著影响管土横向相互作用、轴向阻力和保温性能。本文利用离心模型试验的结果对海底管道动态埋置计算模型进行了校正。该模型使用可塑性理论的元素来捕捉垂直和水平组合加载的影响，并结合周围土壤的软化，因为它是由于管道情绪重塑。在计算过程中考虑了铺设速率、铺设几何形状和海况的影响。将该模型与在三个不同海上站点的现场调查中观察到的铺设管道嵌入数据进行了比较。使用现场测试获得的特定场地土壤参数和理想管道载荷和运动来分别表示海上管道铺设过程中的载荷和位移模式，该模型可以很好地捕获现场调查中测量的最终铺设嵌入。
Subsea pipelines are becoming an increasingly significant element of offshore hydrocarbon developments as exploration moves into deep-water environments further from shore. During the lay process, pipelines are subject to small amplitude vertical and horizontal oscillations, driven by the sea state and lay vessel motions. Centrifuge model tests have been used to simulate these small-amplitude lay effects, with varying degrees of idealization relative to the real lay process. In the soft soils found in deep water, pipe embedment can exceed a diameter or more, thus significantly affecting the lateral pipe–soil interaction, axial resistance, and thermal insulation. In this paper, results from centrifuge model tests are used to calibrate a model for calculating the dynamic embedment of a subsea pipeline. The model uses elements of plasticity theory to capture the effects of combined vertical and horizontal loading, and incorporates the softening of the surrounding soil as it is remoulded due to the pipelinemotions. Influences from the lay rate, lay geometry, and sea state are included in the calculation process. The model is compared with observed as-laid pipeline embedment data fromfield surveys at three different offshore sites. Using site-specific soil parameters obtained from in situ testing and idealized pipe loads and motions to represent the load and displacement patterns during offshore pipe-laying, respectively, the model is shown to capture well the final as-laid embedment measured in the field surveys.