Characteristics of the London Clay from the Terminal 5 site at Heathrow Airport

Hight, D. W.; Gasparre, A.; NISHIMURA, S.; Jardine, R. J.; Coop, M. R.; MINH, N. A.

doi:10.1680/ssc.41080.0016

Cited by 13 publications

(19 citation statements)

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“…The secant bulk stiffness data for the London Clay are reproduced in Figure 2 from Hight et al (2007). These data are also obtained from recent experiments on samples of London Clay from Heathrow Terminal 5.…”

Section: Available Stiffness Datamentioning

confidence: 81%

“…5 mm. The isotropic shear stiffness curve calibrated from the new data of Hight et al (2007) results in a wider and shallower settlement trough, with the maximum settlement of about 8 mm.…”

Section: Results -Short Termmentioning

confidence: 97%

“…Owing to the large scatter in the Hight et al (2007) data in Figure 2, in particular for volumetric strains smaller than 0 . 01%, no new calibration of these data has been performed.…”

Section: Calibration Of Isotropic Stiffnessmentioning

confidence: 99%

“…The shear stiffness data for the London Clay used for calibration are reproduced in Figure 1 from Hight et al (2007). This figure shows the normalised secant undrained Young's modulus, E u /p9, plotted against axial strain, å a , from recent undrained triaxial compression tests on samples of London Clay from the Heathrow Terminal 5 site, from a range of depths and lithological units (Gasparre, 2005).…”

Section: Available Stiffness Datamentioning

confidence: 99%

“…The isotropic secant shear stiffness calibrated from the new data of Hight et al (2007) is shown as a dot-dashed line in Figure 1, whereas the corresponding parameters for the non-linear stiffness model are summarised in Table 1. This curve plots approximately as an average of experimental data, with the elastic plateau chosen at E u /p9 ¼ 500.…”

Section: Calibration Of Isotropic Stiffnessmentioning

confidence: 99%

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Predicting ground movements in London Clay

Jurečič¹,

Zdravković

Jovičić

2013

Proceedings of the Institution of Civil Engineers - Geotechnica

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The necessity of accounting for small-strain behaviour of soils in numerical analyses of the serviceability limit states of geotechnical structures is well established both nationally and internationally. This has led to further development of appropriate soil constitutive models, as well as to further advances in accurate laboratory measurements of smallstrain stiffness. The current paper considers recent laboratory research into the behaviour of London Clay, performed at Imperial College in conjunction with the major ground works for Heathrow Terminal 5 in London, UK. This research has shown the small-strain response of London Clay to be different to that assumed previously and in particular to that determined from good-quality commercial experiments. Both sets of small-strain stiffness data are applied in this paper in finite-element analyses of a deep excavation and a tunnel construction in London Clay, with the objective of investigating their effect on predicted ground movements.

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Section: Available Stiffness Datamentioning

confidence: 81%

“…5 mm. The isotropic shear stiffness curve calibrated from the new data of Hight et al (2007) results in a wider and shallower settlement trough, with the maximum settlement of about 8 mm.…”

Section: Results -Short Termmentioning

confidence: 97%

“…Owing to the large scatter in the Hight et al (2007) data in Figure 2, in particular for volumetric strains smaller than 0 . 01%, no new calibration of these data has been performed.…”

Section: Calibration Of Isotropic Stiffnessmentioning

confidence: 99%

Section: Available Stiffness Datamentioning

confidence: 99%

Section: Calibration Of Isotropic Stiffnessmentioning

confidence: 99%

See 3 more Smart Citations

Predicting ground movements in London Clay

Jurečič¹,

Zdravković

Jovičić

2013

Proceedings of the Institution of Civil Engineers - Geotechnica

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Comparison of displacement field predicted by 2D and 3D finite element modelling of shallow NATM tunnels in clays

Svoboda

Maš́ın

2011

Geotechnik

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The 2D load-reduction method for simulating NATM tunnels using plane strain finite elements is evaluated in the paper by comparison with fully 3D simulations. Three real shallow tunnels in urban environment in different stiff clays were simulated. The soil behaviour was described by an advanced non-linear soil constitutive model based on the hypoplasticity theory. Time-dependent behaviour of shotcrete lining was considered in 3D simulations, whereas constant final stiffness was used in the plane strain analyses. The 2D analyses were thus controlled by a single parameter that accounts for 3D effects. It is shown that for an optimum value of this parameter, the displacement field predicted by the 2D method agrees well with the 3D simulations. In some cases only, a discrepancy was observed in the close vicinity of the tunnel. The controlling parameter was, however, found to be dependent on the problem simulated (for the same material) and also on the material properties (for the same tunnelling problem). Considering the material properties, the shear modulus at very small strain was found to be more influential than the shear modulus at large strain. The initial K 0 stress state did not influence the controlling parameter substantially. Vergleich der Prognose des Verschiebungsfeldes durch 2D-und 3D-FE-Modellierungen von seichten Tunneln im TonDie mit finiten Elementen mit ebenem Spannungszustand arbeitende 2D-Lastreduktionsmethode zur Simulierung von NÖT-Tunneln wird im vorliegenden Aufsatz im Vergleich zu vollen 3D-Simulationen bewertet. Es wurden drei existierende oberflächen-nahe Stadttunnel in verschieden festen Tonböden simuliert. Das Bodenverhalten wurde durch ein komplexes, nicht-lineares Bodenmodell auf Basis der Hypoplastizitätstheorie beschrieben. In den 3D-Simulationen wurde das zeitabhängige Verhalten der Spritzbetonauskleidung untersucht, wohingegen in den Analysen der ebenen Spannungszustände die konstante, endgültige Festigkeit des Betons verwendet wurde. Die 2D-Analysen wurden auf diese Weise durch einen einzelnen Parameter bestimmt, der den 3D-Wirkungen Rechnung trägt. Die Untersuchung zeigt, dass für einen Optimalwert dieses Parameters das mittels der 2D-Methode prognostizierte Verschiebungsfeld weitestgehend mit den 3D-Simulationen übereinstimmt. Nur in einigen Fällen war in unmittelbarer Nähe zum Tunnel eine Diskrepanz zu beobachten. Es wurde jedoch festgestellt, dass der bestimmende Parameter von der Art des simulierten Problems abhängt (für dasselbe Material) und auch von den Materialeigenschaften (für dasselbe Tunnelbauproblem). Für die Materialeigenschaften wurde festgestellt, dass der Schubmodul bei sehr kleinen Spannungen eine größere Rolle spielt als bei großen Spannungen. Der anfängliche K 0 -Lastzustand hatte keinen wesentlichen Einfluss auf den bestimmenden Parameter. Introduction3D numerical analysis is becoming an increasingly affordable tool for predicting deformation and stress redistribution induced by tunnelling. As tunnel excavation is clearly a three dimensional problem, conside...

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Vertical stress distributions around batter piles driven in cross‐anisotropic media

Wang

Lee

Chen

2008

Num Anal Meth Geomechanics

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SUMMARYThis work presents analytical solutions to compute the vertical stresses for a cross-anisotropic half-space due to various loading types by batter piles. The loading types are an embedded point load for an end-bearing pile, uniform skin friction, and linear variation of skin friction for a friction pile. The crossanisotropic planes are parallel to the horizontal ground surface. The proposed solutions can be obtained by utilizing Wang and Liao's solutions for a horizontal and vertical point load acting in the interior of a cross-anisotropic medium. The derived cross-anisotropic solutions using a limiting approach are in perfect agreement with the isotropic solutions of Ramiah and Chickanagappa with the consideration of pile inclination. Additionally, the present solutions are identical to the cross-anisotropic solutions by Wang for the batter angle equals to 0. The influential factors in yielded solutions include the type and degree of geomaterial anisotropy, pile inclination, and distinct loading types. An example is illustrated to clarify the effect of aforementioned factors on the vertical stresses. The parametric results reveal that the stresses considering the geomaterial anisotropy and pile batter differ from those of previous isotropic and cross-anisotropic solutions. Hence, it is imperative to take the pile inclination into account when piles are required to transmit both the axial and lateral loads in the cross-anisotropic media.

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Characteristics of the London Clay from the Terminal 5 site at Heathrow Airport

Cited by 13 publications

References 0 publications

Predicting ground movements in London Clay

Predicting ground movements in London Clay

Comparison of displacement field predicted by 2D and 3D finite element modelling of shallow NATM tunnels in clays

Vertical stress distributions around batter piles driven in cross‐anisotropic media

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