Generalized failure envelope for caisson foundations in cohesive soil: Static and dynamic loading

Gerolymos, Nikos; Zafeirakos, Athanasios; Karapiperis, Konstantinos

doi:10.1016/j.soildyn.2015.07.012

Cited by 49 publications

(25 citation statements)

References 43 publications

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“…They are function of the dimensionless parameter

χ = V / V_{0}^{+}

and can be computed from the following equations:

H_{u} = α_{H} L {((), L / D)}^{β_{H}} {(() 1 + L / D)}^{γ_{H}} {([] 1 + ε_{H} χ - (ε_{H} + 1) χ^{2})}^{ζ_{H}} S_{u} D,

M_{u} = α_{M} L D {((), L / D)}^{β_{M}} {(() 1 + L / D)}^{γ_{M}} {([] 1 + ε_{M} χ - (ε_{M} + 1) χ^{2})}^{ζ_{M}} S_{u} D,

with

α_{H}, β_{H}, γ_{H}, ε_{H}, ζ_{H}, α_{M}, β_{M}, γ_{M}, ε_{M}, ζ_{M}

being parameters function of the soil/pile adhesion factor

α

(

. 1

for smooth case, 1 for rough case), the soil cohesion, and the pile geometry. The failure surface proposed by Gerolymos 2 for caisson foundations with

L / D \leq 4

is quite similar to the proposed equation and fits the data quite well. It is still relevant for geometrical ratios within the range 4‐10.…”

Section: Resultssupporting

confidence: 71%

“…Perfect fit is observed for small to moderate values of

M

and

H

, while a slight discrepancy is apparent close to high curvature point

P_{5}

, corresponding to the maximum moment load. Gerolymos 2 investigated through a series of three‐dimensional nonlinear finite element computations the response of caisson foundations of

1 \leq L / D \leq 3

under a combined planar loading considering the interaction between the vertical and lateral loads. The study provides the following closed‐form expression of the failure surface for caisson foundations, assuming nonlinear interface conditions (

α = . 1

for the smooth case and

α = 1

for the rough case).…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

3D failure envelope of a rigid pile embedded in a cohesive soil using finite element limit analysis

Graine

Krabbenhøft

2020

Num Anal Meth Geomechanics

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In this paper, numerical limit analysis is applied to evaluate the bearing capacity of a single rigid pile embedded in a ponderable homogeneous cohesivefrictionless soil subjected to vertical, horizontal, and moment (VHM) loading combinations. All loads act in the same plane. Accurate lower and upper bounds are calculated using finite element limit analysis code OPTUM G3. As the gap between the bounds hardly exceeds 5%, the average limit load provides a good estimate of the exact ultimate load and can be used with confidence for design purposes. By adopting typical values for the dimensionless pile length-todiameter ratio, most cases of practical interest are treated. The numerical results are compared against failure surfaces predicted by theories from the literature. Comparison shows that previously developed methods can be conservative or slightly overestimates the limit loads. New design charts are provided. The safe loads domain is constructed in the VHM space using the average limit load. Closed-form expressions are proposed to describe the native and the normalized VMH failure envelope as a function of the pile length-to-diameter ratio. In the VH plane, the failure surface is described by an eccentric superellipse, whereas in the MH plane, the limit curve is an inclined ellipse.

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“…They are function of the dimensionless parameter

χ = V / V_{0}^{+}

and can be computed from the following equations:

H_{u} = α_{H} L {((), L / D)}^{β_{H}} {(() 1 + L / D)}^{γ_{H}} {([] 1 + ε_{H} χ - (ε_{H} + 1) χ^{2})}^{ζ_{H}} S_{u} D,

M_{u} = α_{M} L D {((), L / D)}^{β_{M}} {(() 1 + L / D)}^{γ_{M}} {([] 1 + ε_{M} χ - (ε_{M} + 1) χ^{2})}^{ζ_{M}} S_{u} D,

with

α_{H}, β_{H}, γ_{H}, ε_{H}, ζ_{H}, α_{M}, β_{M}, γ_{M}, ε_{M}, ζ_{M}

being parameters function of the soil/pile adhesion factor

α

(

. 1

for smooth case, 1 for rough case), the soil cohesion, and the pile geometry. The failure surface proposed by Gerolymos 2 for caisson foundations with

L / D \leq 4

is quite similar to the proposed equation and fits the data quite well. It is still relevant for geometrical ratios within the range 4‐10.…”

Section: Resultssupporting

confidence: 71%

“…Perfect fit is observed for small to moderate values of

M

and

H

, while a slight discrepancy is apparent close to high curvature point

P_{5}

, corresponding to the maximum moment load. Gerolymos 2 investigated through a series of three‐dimensional nonlinear finite element computations the response of caisson foundations of

1 \leq L / D \leq 3

α = . 1

for the smooth case and

α = 1

for the rough case).…”

Section: Resultsmentioning

confidence: 99%

3D failure envelope of a rigid pile embedded in a cohesive soil using finite element limit analysis

Graine

Krabbenhøft

2020

Num Anal Meth Geomechanics

View full text Add to dashboard Cite

show abstract

“…For an optimum caisson foundation design in the offshore field it is necessary to consider the couplings between the vertical force (V), the horizontal force (H) and the bending moment (M). Previous research studies on the bearing capacity of caisson foundations in sand mainly focused in in-situ tests (Hogervorst, 1980;Houlsby et al, 2006;Tjelta, 1995), model test (Byrne and Houlsby, 2001;Cassidy et al, 2002;Foglia et al, 2015;Gottardi et al, 1999;Ibsen et al, 2013Ibsen et al, , 2014 or finite element method simulations (Gerolymos et al, 2015;Liu et al, 2014;Zafeirakos and Gerolymos, 2016;Jin et al, 2018b). The above experimental or numerical results can be used to construct simplified numerical strategies for design purposes, e.g.…”

Section: Introductionmentioning

confidence: 99%

Advanced numerical modelling of caisson foundations in sand to investigate the failure envelope in the H-M-V space

et al. 2019

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This paper focuses on the identification of the failure envelope of a caisson foundation in sand using an advanced critical state-based sand model (SIMSAND) and the Combined Lagrangian Smoothed Particle Hydrodynamics Method (CLSPH). The parameters of the SIMSAND constitutive model are first calibrated using triaxial tests on Baskarp sand. In order to validate the combined CLSPH-SIMSAND approach, a cone penetration test, model tests and a field test on a reduced scale caisson foundation are simulated. After full numerical validations with different scales from laboratory to in-situ conditions, a numerical parametrical study is then introduced considering different sand properties (density, friction angle, deformability, crushability) and caisson dimensions (soil-structure contact surface area, diameter-depth ratio) and complex combined loading paths to identify the failure envelope in the horizontal force (H), bending moment (M), vertical force (V) space. The influence of the caisson foundation contact surface area, aspect ratio and soil parameters are considered and quantified. Finally, an analytical formula is proposed for the 3D failure envelope in the H-M-V space.

show abstract

“…The finite element method is widely adopted to analyse the nonlinear behaviour of caisson foundations [6][7][8][9][10]. Nevertheless, nonlinear finite element analyses are time-consuming and require considerable skill.…”

Section: Introductionmentioning

confidence: 99%

A hypoplastic macroelement model for a caisson foundation in sand under monotonic and cyclic loadings

et al. 2019

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Nowadays, the numerical analysis of caisson foundations of offshore structures is a big challenge in engineering design. A simple, fast and accurate numerical tool is proposed in this article based on the macroelement concept. The novel macroelement is within the framework of hypoplasticity and can consider static monotonic and cyclic combined (multidirectional) loads for a caisson foundation in sand. The incremental nonlinear constitutive formulas are defined in terms of generalised forces and displacements and an enhanced function of failure surface is introduced. A series of well-documented laboratorial reduced-scale 1g model tests are adopted to validate the novel numerical tool. Results demonstrate a satisfied predictive performance of the proposed macroelement that can be used in caisson foundation design and constitutes an alternative to the traditional finite element analysis.

show abstract

Generalized failure envelope for caisson foundations in cohesive soil: Static and dynamic loading

Cited by 49 publications

References 43 publications

3D failure envelope of a rigid pile embedded in a cohesive soil using finite element limit analysis

3D failure envelope of a rigid pile embedded in a cohesive soil using finite element limit analysis

Advanced numerical modelling of caisson foundations in sand to investigate the failure envelope in the H-M-V space

A hypoplastic macroelement model for a caisson foundation in sand under monotonic and cyclic loadings

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