CEL方法在抛锚贯入深度中的应用研究

    Research on the application of the CEL method in anchor penetration depth

    • 摘要: 船舶的应急抛锚作业会对海底管道的安全构成严重威胁。现有经验公式和理论模型在复杂地质条件下往往适应性不足,尤其难以刻画土体强度在高速贯入过程中的非线性演化。针对上述问题,以商船广泛使用的霍尔锚为对象,采用耦合欧拉-拉格朗日(CEL)方法在静态条件下研究船舶应急抛锚的贯入行为,模型中引入摩尔-库仑本构和Einav应变率软化关系,以反映土体强度的动态衰减;通过罚函数处理锚-土接触界面,并经网格收敛性测试确定58.6万单元的欧拉域划分。以某海上风电场工程水域的淤泥质黏土为背景,计算了2万GT LPG船和5万吨级油船应急抛锚的最大贯入深度,分别得到2.908 m和3.033 m。与DNV能量法和Young公式相比,本方法能更好地反映土体非均质性和大变形特征,将模拟结果与试验数据对比,贯入深度最大误差13.1%,触底速度最大误差16.1%,在工程可接受范围内。结果表明,该方法具有较高的可靠性,符合工程实际,可以为海底管线设计、路径规划及抛锚风险控制提供理论与技术支撑。

       

      Abstract: Emergency anchoring operations pose a serious threat to the safety of subsea pipelines. Existing empirical formulas and theoretical models often show limited adaptability under complex geological conditions, particularly in characterizing the nonlinear evolution of soil strength during high-velocity penetration. To address this problem,this study takes the Hall anchor,which is widely used on merchant ships,as the research object and investigates the penetration behavior of ship emergency anchoring under static conditions using the Coupled Eulerian-Lagrangian(CEL) method. The Mohr-Coulomb constitutive model and the Einav strain-rate softening relationship are introduced to describe the dynamic degradation of soil strength. The anchor-soil contact interface is treated using the penalty function method,and an Eulerian domain with 586 000 elements is determined through a mesh convergence test. Taking the muddy clay in the waters of an offshore wind farm as the engineering background,the maximum penetration depths of emergency anchoring for a 20 000 GT LPG carrier and a 50 000 DWT oil tanker are calculated to be 2.908 m and 3.033 m,respectively. Compared with the DNV energy method and Young's formula,the proposed method can better reflect soil heterogeneity and large-deformation characteristics. The simulation results are further compared with experimental data,showing maximum errors of 13.1% in penetration depth and 16.1% in bottom-impact velocity,both of which are within the acceptable range for engineering applications. The results indicate that the proposed method has high reliability and is consistent with engineering practice,providing theoretical and technical support for subsea pipeline design,route planning,and anchoring risk control.

       

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