Offshore wind developments are moving towards deep-water regions where energy is abundant, visual impact is minimised and the larger turbine sizes can make the energy production more cost-effective. One of the key challenges facing the industry is the development of reliable substructures. While fixed foundation systems are widely used for shallow-water (<60 m) developments, permanent anchors are seen as one of the most viable mooring solutions for floating structures in deep water. In the current study, the pull-out behaviour of square plate anchors in clay was investigated using large-displacement finite-element analysis. The anchor capacity and failure mechanism were considered for a range of embedment ratios and undrained shear strengths. Three distinct modes of anchor failure identified in previous studies were examined through the analysis of four descriptors including: the pull-out capacity of the anchor, the pull-out displacement required to mobilise this capacity, the energy absorbed by the anchor during pull-out and the variation of the pull-out capacity with respect to a normalised overburden pressure. The findings of the study are presented in the form of a series of charts that can aid design through understanding of the factors controlling the development of anchor failure modes, in addition to identifying the transition point between different failure mechanisms.

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The Cone Penetration Test (CPT) has been extensively used in geotechnical engineering, to evaluate the properties of wide range of soils. Numerical simulations of CPT involves large deformations in the soil domain which causes numerical difficulties in traditional finite element analysis. Early numerical studies used simplifying assumptions such as wished-in-place condition and in-situ stress distribution as the initial stress state of the soil domain. Recent developments in finite element analysis allow large deformation analyses to be performed. This paper presents the results of the continuous penetration of cone in single-layer and double-layer clay using the Coupled Eulerian Lagrangian (CEL) method. Performance of the CEL technique was in modelling the cone penetration test was validated against the existing studies. Then, a parametric study was performed to develop a correlation between the cone bearing factor and rigidity index of the clay. The proposed correlation showed a very good agreement with the existing experimental and numerical correlations. The cone penetration test in double-layer clay was simulated. The results suggested that CEL analysis is a reliable technique in modelling large deformation problem of cone penetration test.@en

Offshore wind developments are moving towards deep water where the energy is abundant and visual and sound interference is minimised. However, construction in deep water poses several challenges to developers, among which are the high cost of operation and material transport. The current study addresses the behaviour of a novel foundation system (pending US patent) that aims at minimising the cost of deployment for emerging offshore wind facilities. To this end, the preliminary results of an offshore field test on the small scale dynamically installed anchor are presented and the testing methodologies are briefly outlined. The results provide insights into the behaviour of the anchor as it is released into the water column, impacts with the seabed, and finally, achieves it maximum penetration depth. This is enabled through a detailed study of the data obtained from an accelerometer built into the anchor, which tracks the anchor motion over the course of its deployment. Overall, the findings in this research contribute to an enhanced understanding of the behaviour of dynamically installed anchors as perceived through field tests.@en