船锚在软土中的运动形式研究

Study on Behavior of Drag Anchor in Soft Soils

船锚在软土中由于风浪的作用会随着船舶而移动,这可能会造成海底预埋电缆被损坏。堆石保护是当前普遍采用的对海底电缆进行保护的方法,但是对这种保护措施至今还没有成熟的施工规范。为了完善海底电缆堆石保护的各项设计参数,研究船锚在软土中的运动规律是非常必要的。在锚爪二维非线性有限元分析的基础上,建立了船锚运动轨迹与其屈服荷载之间的本构关系,结合锚链在软土中的研究成果,提出一种新的船锚运动轨迹预测计算方式。最后,根据荷兰Deltares科研所计划实施离心机试验的计算参数,对试验结果作出模拟预测。

Soft soils usually do not make a good anchorage for vessels, and in the presence of a strong current, vessels are likely to drift, dragging their anchors across pipelines. One solution is to bury the pipeline into the seabed by rocks. Although this solution is now commonly used, there are no formal rules or guidelines to assist in the design. It is necessary to provide an insight into interaction mechanism between anchor, anchor chain and the soil. In this thesis, a plastic yield locus in terms of loads parallel and perpendicular to the anchor fluke and moment load is set up in 2D finite element analysis. Furthermore, a constitutive model is set-up to describe the relationship between the yield loads and anchor fluke＇s behavior. Combined the fluke constitutive model with anchor chain equilibrium equations, a new analytical design procedure is introduced for the prediction of drag anchor behavior in soft clay. At last, a prediction is made for drag anchor centrifuge test in Dehares.