Discussion: A review on the behaviour of helical piles as a potential offshore foundation system
Discussion: A review on the behaviour of helical piles as a potential offshore foundation system
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DOI：
10.1080/1064119x.2020.1793040
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发表时间：
2020-07
影响因子：
2.2
通讯作者：
S. Ullah;Yuxia Hu
中科院分区：
文献类型：
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作者：
S. Ullah;Yuxia Hu
摘要螺旋桩作为一种有吸引力的基础系统，在海上工程中得到了越来越多的重视。目前在将这一技术转移到海外方面存在着重大的研究差距，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。我们专注于耦合欧拉-拉格朗日（CEL）大变形有限元（LDFE）建模技术，该技术是商用的，可用于模拟三维安装过程，考虑应变率和软化效应在软近海粘土。以L = 7.5 m长的螺旋桩为模型，在直径d = 0.5 m的中心轴上连接一根或两根大直径螺旋（D = 2 m），应变率和软化的净效应是增加安装扭矩。对于所研究的海上粘土和桩几何形状，测得的扭矩在200-400 kN.m的范围内。额外的螺旋增加了上举力，但增加的程度小于测量的扭矩。重塑引起的强度降低被认为是在25-33%的范围内的完整粘土强度。探讨了海上螺旋桩基础的提取和再利用问题。
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.