鱼雷锚在钙质砂床中的贯入深度研究

鱼雷锚安装简单、快速，是一种在海洋工程中具有良好应用前景的锚固结构，其在钙质砂床的贯入深度关乎其系泊结构物的稳定性和抗风浪能力。基于耦合的SPH (光滑粒子流体动力学法)和FEM (有限元法)算法，针对Richardson(2008)研究的鱼雷锚建立了有限元模型，在Abaqus平台上，数值模拟了该鱼雷锚在钙质砂床中的贯入深度，并模拟了不同的贯入速度、锚重量和锚-土界面间的摩擦系数等对鱼雷锚贯入深度的影响。通过对比数值模拟结果与Richardson(2008)提供的实验结果可知，耦合的SPH-FEM算法可以快速准确地模拟鱼雷锚在钙质砂床中的贯入深度。此外，由参数化研究可知，鱼雷锚的锚重、贯入速度和锚-土间摩擦系数对鱼雷锚的贯入深度影响显著。特别地，当贯入速度大于某一临界值时，贯入深度基本上与贯入速度成正比。最后，基于Richardson实验数据和本次数值模拟获得的65组数据，从能量法的角度提出了鱼雷锚在钙质砂床中贯入深度的预测公式，为动力锚的设计和应用提供理论支撑。此外，经初步验证，该公式也可用于预测DPAⅢ动力贯入锚在钙质砂床中的贯入深度。

The study on penetration depth of a torpedo anchor in calcareous sandy bed

Torpedo anchor is a kind of anchorage structure with good application prospects due to its simple, fast and economical installation in ocean engineering. The penetration depth of the torpedo anchor in calcareous sandy bed is crucial to obtain its sufficient holding force for its moored structure. In this study, the torpedo anchor studied by RICHARDSON (2008) is used. Then, based on the coupled SPH (smooth particle hydrodynamics) and FEM (finite element method), the penetration depth of the torpedo anchor in calcareous sandy bed is simulated on Abaqus platform. In the numerical simulation, the influences of the impact velocity, anchor weight and friction coefficient between anchor and soil interface on the penetration depth are studied comprehensively. By comparing the numerical simulation results with the experimental results obtained by RICHARDSON (2008),we show that the coupled SPH-FEM algorithm is able to quickly and accurately simulate the penetration depth of torpedo anchor in sandy seabed. Besides, according to parametric study, the weight and impact velocity of torpedo anchor and the friction coefficient between anchor and soil would have significant influence on the penetration depths. Specifically, when the impact velocity is larger than a critical value, the penetration depth would vary approximately linearly along with the impact velocity. Finally, based on Richardson’s experimental data and 65 sets of numerical data obtained herein, an energy method is proposed to predict the penetration depth of torpedo anchor in calcareous sandy bed, which can be used for the design of dynamic anchor. Furthermore, this method is also applicable to the prediction of the penetration depth of DPA III dynamically installed anchor in calcareous sandy bed.