Effect of Strain Rate and Strain Softening on the Penetration Resistance of Spudcan Foundations on Clay

Hossain, Muhammad Shazzad; Randolph, Mark

doi:10.1061/(asce)1532-3641(2009)9:3(122)

Cited by 120 publications

(54 citation statements)

References 30 publications

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“…The flow patterns revealed at different stages of spudcan penetration are also entirely consistent with the centrifuge observations (see Fig. 7 of Hossain & Randolph, 2009a). From the start of penetration the soil deformation is directed predominantly vertically downwards to the lower layer, with no upwards movement (see Fig.…”

Section: Behaviour Of Spudcan Foundations Comparison Between Ldfe Ressupporting

confidence: 86%

“…The corresponding load-penetration responses (from the corresponding fullspudcan centrifuge test) are also consistent, as shown in Fig. 4, particularly after minor adjustment to allow for effects of partial remoulding of the soil as the spudcan penetrates (Hossain & Randolph, 2009a). The good agreement with the model test provides confidence in the accuracy of the LDFE results.…”

Section: Behaviour Of Spudcan Foundations Comparison Between Ldfe Ressupporting

confidence: 66%

“…3, also Fig. 4 of Hossain & Randolph, 2009a). The shape was chosen to mimic the centrifuge spudcan model, which was fabricated based on the spudcans used in practice with the jack-up rig 'Marathon LeTourneau Design, Class 82-SDC', as illustrated by Menzies & Roper (2008).…”

Section: Numerical Analysis Geometry and Parametersmentioning

confidence: 99%

“…Practical ranges of soil properties, as reported in the literature, are summarised by Hossain & Randolph (2009a). The maximum top layer undrained strength of practical interest is taken as s ut ¼ 200 kPa, with minimum bottom layer strength of s ubs ¼ 10 kPa, and lower layer strength gradient k typically varying between 0 and 2 kPa/m.…”

Section: Numerical Analysis Geometry and Parametersmentioning

confidence: 99%

“…A comparison is presented here between one of the model tests (test E1UU-III-T 7, Table 3; Hossain & Randolph, 2009a) and an LDFE simulation. The test modelled a spudcan of prototype diameter 6 m penetrating a (nominally) uniform strength top layer, with t/D ¼ 1, overlying a uniform strength bottom layer.…”

Section: Behaviour Of Spudcan Foundations Comparison Between Ldfe Resmentioning

confidence: 99%

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Deep-penetrating spudcan foundations on layered clays: numerical analysis

Hossain¹,

Randolph²

2010

Géotechnique

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This paper presents results of large deformation finite element (LDFE) analyses that investigate the penetration response of deep-penetrating spudcan foundations in stratified soil comprising a strong clay layer overlying weaker clay. Such strength profiles give rise to potential punchthrough failure, with a local maximum penetration resistance followed by some reduction. The paper is a companion paper to one that presents results from centrifuge model tests of the same problem, with the overall aim being to investigate the potential for punch-through failure and its severity, as a basis for improving design methods for evaluating spudcan penetration. The LDFE analyses have simulated continuous penetration of smooth and rough spudcan foundations from the sea-bed surface. A detailed parametric study has been undertaken, exploring the relevant range of layer thickness (relative to the spudcan diameter), strength ratios and spudcan base roughness. The results have been validated against previously published results and the centrifuge test data presented in a companion paper. Excellent agreement was obtained between the results from LDFE analyses and centrifuge tests. As the ratio of the shear strength of the bottom layer to that of the top layer decreased, upwards soil flow around the spudcan shoulder became less pronounced and the failure mechanism was dominated by a steep-sided plug of soil from the top layer being forced deep into the lower layer. The potential for severe punch-through was demonstrated by a significant reduction in the resistance profile as the spudcan approached the interface between the two layers. A preliminary design chart is proposed to estimate the cavity depth above the penetrating spudcan, which was significantly greater than that for a single layer clay. The penetration responses have been presented in terms of profiles of normalised net bearing pressure for a range of layer geometries and soil properties. Potential punchthrough occurred for all cases where the strength ratio was less than or equal to 0 . 6, with the reduction in resistance being greater the lower the strength ratio of the underlying layer to the upper layer, and the thicker the upper layer, but reducing as the strength gradient in the lower layer increased. The current approach suggested in offshore design guidelines is shown to underestimate the penetration resistance significantly, in most cases, and give poor estimates of the likelihood and severity of spudcan punch-through.KEYWORDS: bearing capacity; clays; failure; footings/foundations; numerical modelling; offshore engineering La présente communication présente les résultats d'analyses de larges déformations en éléments finis (LDEF) examinant la réaction à la pénétration de fondations à forte pénétration dans des sols stratifiés, comportant une couche d'argile résistante recouvrant une couche d'argile plus faible. Ces profils de résistance donnent lieu à un risque de rupture à « punch-through », dans le cadre de laquelle une résistance maximale locale à la pénétr...

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Section: Behaviour Of Spudcan Foundations Comparison Between Ldfe Ressupporting

confidence: 86%

Section: Behaviour Of Spudcan Foundations Comparison Between Ldfe Ressupporting

confidence: 66%

Section: Numerical Analysis Geometry and Parametersmentioning

confidence: 99%

Section: Numerical Analysis Geometry and Parametersmentioning

confidence: 99%

Section: Behaviour Of Spudcan Foundations Comparison Between Ldfe Resmentioning

confidence: 99%

See 3 more Smart Citations

Deep-penetrating spudcan foundations on layered clays: numerical analysis

Hossain¹,

Randolph²

2010

Géotechnique

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Encyclopedia of Maritime and Offshore Engineering

Talas¹,

Menachof

Harris³

2017

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Spudcan–Seabed Interaction

Bienen

Hossain

2018

Encyclopedia of Maritime and Offshore Engineering

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Most offshore drilling in shallow to moderate water depths is performed from self‐elevating jack‐up rigs due to their proven flexibility, mobility, and cost‐effectiveness. Today's jack‐ups typically consist of a buoyant triangular platform supported by three independent truss legs, each attached to a large 10–20 m diameter spudcan, which are jacked into the seabed. These transfer the loads from the platform to the seabed soil. This article provides an overview of the state of practice of geotechnical design considerations for spudcan–seabed interaction, covering the full life cycle including (i) installation, (ii) operation, and (iii) demobilization.

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Effect of Strain Rate and Strain Softening on the Penetration Resistance of Spudcan Foundations on Clay

Cited by 120 publications

References 30 publications

Deep-penetrating spudcan foundations on layered clays: numerical analysis

Deep-penetrating spudcan foundations on layered clays: numerical analysis

Encyclopedia of Maritime and Offshore Engineering

Spudcan–Seabed Interaction

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