摘要
拖曳锚在海床土中的嵌入行为和运动轨迹不只是一个复杂的工程问题，同时也是一个包含许多科学内涵的研究专题。现有研究中，几乎所有的轨迹预测方法都需要进行数值增量计算。本文通过提出拖曳锚的运动模型并进行一系列数学推导，建立了可以预测拖曳锚嵌入运动轨迹的理论分析方法。文中提出并进行详细描述的许多概念不仅物理意义明确、在理论框架中不可或缺，更对我们深入理解拖曳嵌入这一工程问题具有重要的意义。
拖曳安装缆绳尤其是嵌入土体部分的嵌入缆对拖曳锚的嵌入行为和运动轨迹具有重要影响，正确理解和描述嵌入缆的反悬链特性对改善锚的嵌入行为、精确预测锚的轨迹以及解决其在工程应用中的安装定位问题均有着重要意义。对反悬链问题的调研表明，嵌入缆绳的反悬链形态几乎都需要通过数值增量方法进行求解。在本文中，基于嵌入缆绳的力学模型，通过建立缆绳张力与几何形态间的关系以及锚与缆绳的作用方程，获得了适用于均质土和线性土的反悬链方程以及用于计算嵌入缆绳长度的表达式，嵌入点位置也可通过推导出的反悬链方程进行求解。
开展了模型水槽实验以研究拖曳缆绳在海床土中的反悬链特性。通过探索并运用可实时测量嵌入缆的反悬链形态以及捕捉嵌入点运动规律等特性的实验技术，对推导出的反悬链方程和有效缆长方程等进行了考察和验证。实验结果也证明了所发展的运动模型和轨迹预测方法的有效性和分析精度。本文提出的运动模型和嵌入运动轨迹的理论分析方法，从一个全新的视角诠释了锚在海床土中的运动行为，对确定性、理论性地分析拖曳锚的一系列相关研究具有重要价值。
The penetration behavior and trajectory of drag anchors in seabed soils is notonly a complicated engineering problem, but also an research topic with lots ofscientific meanings. Nearly all the present methods that are capable of predicting thetrajectory of drag anchors need a numerical incremental computation. Based on akinematic model and a series of mathematical derivations, a theoretical frameworkfor predicting the trajectory of drag anchors is established. The concepts put forwardand described in detail in the paper are not only necessary for the theoreticalframework but also meaningful to further understanding of the engineering problemdue to clear physical background.
The penetration behavior and trajectory of the drag anchor in seabed soils iscontrolled by the installation line especially the segment embedded in the soil.Correctly understanding and describing reverse catenary properties of the embeddedline is crucial for improving the drag embedment performance, precisely predictingthe anchor trajectory, and solving the positioning problem in offshore applications.The investigation on reverse catenary problems demonstrates that, the reversecatenary shape of the embedded line has to be solved almost through numericalincremental methods. In the present study, based on the mechanical model for theembedded line, the relationship between the tension and geometry of the embeddedline, and the interactional equation between the anchor and embedded line are derived.The reverse catenary equation and the expression for calculating the length of theembedded line are obtained both for soils with a uniform strength and with a linearstrength, and the position of the embedment point can be successfully solved through the derived reverse catenary equation.
The model flume experiments are carried out to research the revese catenarycharacteristics of drag line in seabed soils. An experiment technique for real-timemeasuring the reverse catenary shape and capturing the embedment point is alsodeveloped. The accuracy of the developed reverse catenary equation and effectivelength equation is verified by model experiments. Experimental studies have provedthe effectiveness and veracity of the kinematic model and theoretical framework forpredicting the trajectory. The proposed kinematic model and the theoretical predictionmethoed of the kinematic trajectory may provide a new angle of view to understandthe anchor kinematic behaviors in soils, and be valuable for deterministic andtheoretical analysis of drag anchors.
引文
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