Numerical study on pull-out capacity of torpedo anchors in clay

Abstract

This paper reports the results from dynamic finite-element analyses undertaken to provide insight into the behaviour of torpedo anchors during pullout in non-homogeneous clay. The results were validated against field data prior to undertaking a parametric study, exploring the relevant range of parameters in terms of installation effect, impact velocity, anchor geometry, padeye position, pullout angle. Installation method (e.g. quasi-static and dynamic installation) has shown significant influence on the vertical pullout capacity, but that influence reduced to marginal for lateral pullout. The inclined pullout capacity was dictated by the anchor weight and fully mobilised anchor-soil contact surface area and consequently the capacity increased with increasing the number of fins. Due to the lower weight and total surface area, the 45° (at the padeye) pullout capacity of the finless anchor was 29% of that of the considered four-fin anchor. The results showed that this percentage can be increased to 83% by shifting the padeye location of the finless anchor to 0·56 times the anchor shaft length from the top. Anchor capacity under inclined pullout loading was presented as failure envelopes expressed in terms of dimensionless vertical and horizontal components, which lied between the envelops developed for piles and embedded foundations.

Numerical investigation of novel dynamic installed fish anchors in clay and calcareous silt

“…Generally, the deeper embedment depths of DIAs guarantee higher pullout capacity due to the increase in shear strength (Richardson et al, 2009;O'Loughlin et al, 2009O'Loughlin et al, , 2013Kim and Hossain, 2016). In addition, several studies have demonstrated that the lowered padeye position may allow the anchor to embed further (through diving) during pullout (Tian et al, 2014;Liu et al, 2016b;Zhao et al, 2016;Kim and Hossain, 2017).…”

Global jack-up rig behaviour next to a footprint

“…3D LDFE analyses were carried out using the coupled Eulerian-Lagrangian (CEL) approach in the commercial Finite Element (FE) package ABAQUS/Explicit (Version 6.12) [26] [27][28][29][30][31][32][33][34][35] have investigated various geotechnical problems using the CEL approach and provided evidence that it is applicable to solve problems involving large deformations. Extensive background information about CEL, spudcan installation and footprint modelling can be found in Jun et al, Zheng et al and Hu et al [23,24,35,36]; this information is not repeated here.…”

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“…The simulation was fully integrated taking into account the disturbed soil conditions through installation of the anchor for the loading stage [19]. An inclined loading, instead of an inclined displacement, was applied at the anchor padeye ( a ) to obtain apparent anchor trajectory.…”