Abstract Helical piles have emerged as an attractive foundation system for offshore applications with renewed interest from the offshore community. Significant research gap currently exists in transferring this technology offshore and this paper discusses how existing and emerging knowledge can be successfully used to bridge some of the gaps. We focus on the Coupled Eulerian Lagrangian (CEL) large deformation finite element (LDFE) modelling technique that is commercially available and can be used to model the three-dimensional installation process with consideration of strain rate and softening effects in soft offshore clays. A helical pile of L = 7.5 m long is modelled with one or two large-diameter helices (D = 2 m) attached to a central shaft of d = 0.5 m in diameter.The net effect of strain rate and softening is to increase the installation torque. The measured torque is within the range of 200–400 kN.m for the offshore clay and the pile geometry studied. Additional helices increase the uplift force but to a lesser degree than that of the measured torque. Remoulding induced strength reduction is found to be within the range of 25–33% of the intact clay strength. Issues of extracting and reusing offshore helical pile foundations are discussed.

中文翻译：

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讨论：作为潜在的海上基础系统的螺旋桩行为的回顾

摘要 螺旋桩已成为海上应用的有吸引力的基础系统，重新引起了海上社区的兴趣。目前在将该技术转移到海外方面存在重大研究差距，本文讨论了如何成功地利用现有和新兴知识来弥合一些差距。我们专注于商业上可用的耦合欧拉拉格朗日 (CEL) 大变形有限元 (LDFE) 建模技术，可用于在考虑应变率和软质海上粘土软化效应的情况下对三维安装过程进行建模。一个 L = 7.5 m 长的螺旋桩被建模为一个或两个大直径螺旋 (D = 2 m) 连接到一个直径为 d = 0.5 m 的中心轴。应变率和软化的净效应是增加安装扭矩。对于海上粘土和所研究的桩几何形状，测得的扭矩在 200-400 kN.m 的范围内。额外的螺旋会增加提升力，但程度低于测量扭矩。发现重塑引起的强度降低在完整粘土强度的 25-33% 范围内。讨论了海上螺旋桩基础的提取和再利用问题。