Numerical Simulation On The Penetration Process Of The OMNI-Max Anchor With A Booster In Clay

The OMNI-Max anchor is a mooring foundation that relies on its own gravitational energy and free fall in the water to gain kinetic energy into the seabed.Due to the advantages of cost-effective and time-efficient,it has been applied in the Gulf of Mexico and West Africa.However,compared with other types of anchors,the OMNI-Max anchor has a lighter weight,a larger surface area and a relatively complex shape.These features result in a shallower depth of penetration in seabed with a large strength gradient,while a shallower penetration depth results in a lower bearing capacity,and the anchor has the risk of being pulled out.In order to solve this problem,the research team proposed the concept of booster adding at the tail of the anchor.It is expected to increase the penetration depth of the anchor by increasing the gravitational and kinetic energies.The research team carried out a model test on the hydrodynamic characteristics of the booster and the hybrid anchor(an OMNI-Max anchor with a booster)and the penetration process in the clay,and verified the effectiveness of the booster.However,the effects of strain-rate and strain-softening of seabed soil on the penetration depth of hybrid anchor is still unclear,so the first part of this article used the finite element software ABAQUS 6.14 to simulate the penetration process of the OMNI-Max anchor with a booster in normally consolidated clay by the coupled Eulerian–Lagrangian(CEL)approach.The effects of impact velocity,booster weight,strain-rate parameter,reference shear strain-rate,strain-softening parameters and soil shear strength on the penetration depth of the anchor were investigated.The results showed that the soil strength has the greatest influence on the penetration depth,the impact velocity and the booster weight also have a great influence and the effects of strain-rate and strain-softening on the penetration depth were relatively small.The second part of this article proposed prediction models of penetration depth based on total energy of the anchor and differential equation of motion.The energy prediction model can quickly predict the penetration depth by establishing the relationship between penetration depth and total energy of the anchor,and the prediction model based on the differential equation of motion can determine the change process of all components acting on the anchor,and can also obtain the velocity-penetration depth curve of the penetration process of the anchor,so as to predict the penetration depth more accurately,which provide theoretical support for the installation and design of dynamically installed anchors in practical projects.