337 results found
Aldridge TR, Carrington TM, Jardine RJ, et al., 2011, BP Clair Phase 1 - Pile driveability and capacity in extremely hard till, Pages: 477-482
Evans et al. (2010) describe how the foundation engineering for BP's Clair Phase 1 Drilling and Production Platform, West of Shetland, UK, had to consider tills with unprecedentedly high undrained shear strengths and unit weights. Boulders were also present. This paper describes the technical approach taken by BP's foundation assurance team in addressing these challenging conditions, focusing principally on driveability and axial capacity. Advanced field and laboratory investigations were conducted to allow a range of analyses that explicitly considered the effects of cyclic loading, group action, strain softening and possible pilot hole drilling. Instrumented advance driving trials were conducted, while the main jacket installation was also instrumented and back-up drilling options mobilised in case of harder-than-expected driving. © 2011 Taylor & Francis Group, London.
Shen CH, O'Sullivan C, Jardine RJ, 2011, A micromechanical investigation of drained simple shear tests Deformation Characteristics of Geomaterials, Seoul, Korea, 5th International Symposium on Deformation Characteristics of Geomaterials, Publisher: Hanrimwon, Pages: 314-321
Jardine RJ, Aldridge T, Evans TG, 2011, Offshore foundation engineering in extremely dense glacial tills West of the Shetland Islands., 15th European Conference on Soil Mechanics and Geotechnical Engineering (ECSMGE), Publisher: Millpress, Pages: 879-884
Wilkinson S, Brosse A, Coop MR, et al., 2011, An Integrated Geotechnical Study of UK Mudrocks, 15th European Conference on Soil Mechanics and Geotechnical Engineering (ECSMGE), Publisher: Millpress, Pages: 305-310
Brosse A, Hosseini Kamal R, Jardine RJ, et al., 2011, Measuring the static and dynamic small strain stiffness of UK mudrocks, 15th European Conference on Soil Mechanics and Geotechnical Engineering (ECSMGE), Publisher: Millpress, Pages: 137-142
Altuhafi F, Jardine RJ, 2011, Effect of particle breakage and strain path reversal on the properties of sands located near to driven piles, Seoul, Korea, 5th International Symposium on Deformation Characteristics of Geomaterials, Publisher: Hanrimwon, Pages: 386-395
Anh-Minh N, Nishimura S, Takahashi A, et al., 2011, On the control systems and instrumentation required to investigate the anisotropy of stiff clays and mudrocks through Hollow Cylinder Tests, Seoul, Korea, 5th International Symposium on Deformation Characteristics of Geomaterials, Publisher: Hanrimwon, Pages: 287-294
Rimoy SP, Jardine RJ, 2011, Strain accumulation in a silica sand due to creep after normal compression, and during sustained low-level cyclic loading, Seoul, Korea, 5th International Symposium on Deformation Characteristics of Geomaterials, Publisher: Hanrimwon, Pages: 463-470
Nishimura S, Minh NA, Jardine RJ, 2011, Shear strength anisotropy of natural London Clay, Pages: 97-110
The paper reports the shear strength anisotropy of the natural, highly overconsolidated, London Clay from Heathrow Terminal 5 as established by comprehensive hollow cylinder apparatus (HCA) testing. Multiple high-quality block samples from 5.2 m and 10.5 m below ground level provided samples for suites of undrained stress-path shear tests performed after consolidation to effective stress states similar to those estimated in situ. The direction of the major principal stress axis, α (or of the principal stress increment, αdσ), and relative magnitude of the intermediate principal stress, b = (σ2 - σ3)/ (σ1 - σ3), were chosen as the controlled stress-related variables and their influence on the peak shear strength was investigated. Strong shear strength anisotropy was proven, and a potential effect of the parameter b was also detected. With b = 0.5, for example, a minimum was noted in peak q/p′ at around α = 45 67°, and the maximum value, which was larger by some 40%, developed at α = 0°. A limited set of data obtained with larger test specimens suggested a possibility that loading with α = 90° could also lead to relatively low shear strength. The pre-failure pore water pressure development reflected anisotropy of the deformation characteristics at smaller strains and contributed to the total-stress undrained shear strength anisotropy. Regarding the influence of b, the Mohr Coulomb failure line passing through the data for b = 0 or 1 provided a lower bound of all the data for a given value of α. The investigation of anisotropy was extended to deeper horizons of the stratum through profiling tests involving triaxial extension and simple shear conditions. Although the results confirmed the general patterns of anisotropy observed at 5.2 and 10.5 m below ground level, the degree of anisotropy appeared to become stronger with depth.
Gasparre A, Nishimura S, Minh NA, et al., 2011, The stiffness of natural London Clay, Pages: 81-95, ISBN: 9780727741080
An investigation of natural London Clay is reported involving advanced triaxial, hollow cylinder apparatus (HCA) and dynamic testing techniques. Significant anisotropy was revealed at all scales of deformation, and the framework of cross-anisotropic elasticity was found to apply broadly to the initial elastic behaviour. The stiffness parameters obtained by independent techniques generally exhibited good agreement, with the greatest deviation being seen in the Poisson's ratios, which fell far from the values usually assumed in conventional foundation analysis. Probing tests established the limits to the elastic domain over a range of depths, showing that these scaled in proportion to the mean effective stress level, as did those of a second kinematic surface that surrounded the elastic demain. Once engaged, this second surface signified a new pattern of strain increment directions, faster elastic-plastic stiffness decay with strain, and also a greater dependence of behaviour on recent stress history. However, the two kinematic surfaces cover a relatively small proportion of the admissible stress space, and behaviour at larger strains is both anisotropic and strongly non-linear, features that affect profoundly the soil displacements induced by geotechnical construction in this deposit.
Gasparre A, Nishimura S, Coop MR, et al., 2011, The influence of structure on the behaviour of London Clay, Pages: 67-79, ISBN: 9780727741080
An intensive investigation is described into the London Clay units from Heathrow Terminal 5. Intrinsic properties and composition were established, and relating the behaviour of intact and reconstituted samples allowed the effects of the clay's natural structure to be identified at all depths. Structure varied between units, but some general features emerged that have not been seen in other stiff clays. In particular, intact samples follow paths under isotropic or K0 compression that fail to provide well-defined gross yield points, or converge with the unit's intrinsic compression lines. Structure contributes to the enhanced shear strength of intact unfissured clay and affects the initial stiffness relationships. Some identifiable features of the intact units' fabric correlated directly with their behaviour. Natural fissures within the clay, the most important mesofabric feature, had an important impact on shear strength and led to an unusual pattern of directional dependence, and particle orientation trends identified by scanning electron microscopy governed the strong elastic stiffness anisotropy. The potential for destructuration through swelling to low effective stresses was also studied and found significant for subsequent volumetric compression behaviour, but not for shearing. Hight et al. synthesise the data from this and companion papers presented by the authors, and discuss the practical consequences of the results obtained.
Hight DW, Gasparre A, Nishimura S, et al., 2011, Characteristics of the London Clay from the terminal 5 site at Heathrow Airport, Pages: 167-182
The innovative engineering approach adopted for the new Terminal 5 at Heathrow Airport called for an advanced investigation of the London Clay strata, including detailed in situ profiling and stress path laboratory testing on high-quality rotary-cored samples. Although the scope of the investigations exceeded that normally specified for conventional design, questions relating to the structure and anisotropy of stiffness and strength of the clay remained that could not be answered. Further research was required, and the deep excavations at the site provided the opportunity for a team from Imperial College to take multiple block samples from three depths, supplemented by two additional dedicated rotary-cored boreholes. Intensive research was performed at Imperial College on these samples, as described in three companion papers by Gasparre et al. and Nishimura et al. This overview paper integrates the findings from the recent research with those from the commercial investigation and with earlier studies to extend our understanding of the geology and key characteristics of this stiff clay, and their variation with depth. The influence of lithology, structure and destructuring is examined, and the practical implications of the work are discussed.
Ho TYK, Jardine RJ, Anh-Minh N, 2011, Large-displacement interface shear between steel and granular media, GEOTECHNIQUE, Vol: 61, Pages: 221-234, ISSN: 0016-8505
Altuhafi F, Jardine RJ, 2011, Effect of particle breakage and strain path reversal on the properties of sands located near to driven piles, 5th International Symposium on Deformation Characteristics of Geomaterials (IS), Publisher: IOS PRESS, Pages: 388-395
Shen C-K, O'Sullivan C, Jardine RJ, 2011, A Micromechanical Investigation of Drained Simple Shear Tests, 5th International Symposium on Deformation Characteristics of Geomaterials (IS), Publisher: IOS PRESS, Pages: 314-321
Rimoy SP, Jardine RJ, 2011, On strain accumulation in a silica sand under creep and low level cyclic loading, 5th International Symposium on Deformation Characteristics of Geomaterials (IS), Publisher: IOS PRESS, Pages: 463-470
Jardine RJ, 2011, Characterization of mudrocks: a practical application of advanced laboratory testing, JOURNAL OF ZHEJIANG UNIVERSITY-SCIENCE A, Vol: 12, Pages: 1-14, ISSN: 1673-565X
Foray P, Tsuha C, Silva M, et al., 2011, Soil-pile interaction on an instrumented pile under cyclic axial loads in sand, 5th International Conference on Earthquake Geotechnical Engineering
hu M, O'Sullivan C, Jardine RR, et al., 2010, Stress-induced anisotropy in sand under cyclic loading, International Symposium on Geomechanics and Geotechnics - From Micro to Macro, Publisher: SPRINGER, Pages: 469-476, ISSN: 1434-5021
Hu M, O'Sullivan C, Jardine RR, et al., 2010, Study on the deformation of loose sand under cyclic loading by DEM simulation, Pages: 212-219, ISSN: 0895-0563
The extensive use of granular materials as roadbeds accelerates the study of sand behavior under cyclic loading. While several studies have been done on sand deformation under cyclic loading, little information is available on the explanations for this behavior. By discrete element method (DEM) simulation, this paper offered a preliminary insight into particles interaction of loose sand which controls the material's stress-strain behavior. A 2-D 'sample' of 896 'quartz' disks, with diameters of 0.20, 0.25 and 0.30mm, was produced by self-gravity sediment. Then it was K0 loaded to t' = 127 kPa, at which point, the sample started to be cyclically loaded for 5000 cycles when t' kept constant. Cyclic amplitudes varied from 0.02 to0.04 t'. Increasing strain accumulation with increased number of cycles was observed. For smaller cyclic amplitude, strain accumulation increased smoothly, but for larger one, strain accumulation increased erratically after a large number of cycles. The coordination number variation during cycling load was considered to be responsible for this phenomenon. Induced anisotropy was observed, and it could be explained by deviatoric fabric analysis. © 2010 ASCE.
Hu M, O'Sullivan C, Jardine RJ, et al., 2010, Stress induced anisotropy in sand under cyclic loading, Granular Matter, Pages: 469-476
Aldridge TR, Carrington TM, Jardine RJ, et al., 2010, Driven pile design in extremely hard till for BP’s Clair 1 platform, 2nd International Symposium on Frontiers in Offshore Geotechnics, Publisher: CRC Press (UK), Pages: 477-482
Foray PY, Tsuha CHC, Silva M, et al., 2010, Stress paths measured around a cyclically loaded pile in a calibration chamber, London, International Conference on Physical Modelling in Geotechnics, Publisher: CRC Press (UK), Pages: 933-939
Evans TG, Finnie I, Little R, et al., 2010, BP Clair Phase 1 - Design and assurance of driven piled foundations in extremely hard till, 2nd International Symposium on Frontiers in Offshore Geotechnics, Publisher: CRC Press (UK), Pages: 495-500
Yang ZX, Jardine RJ, Zhu BT, et al., 2010, Sand grain crushing and interface shearing during displacement pile installation in sand, GEOTECHNIQUE, Vol: 60, Pages: 469-482, ISSN: 0016-8505
Jardine RJ, 2010, EXPERIMENTAL ARRANGEMENTS FOR INVESTIGATION OF SOIL STRESSES DEVELOPED AROUND A DISPLACEMENT PILE THE USE OF MINIATURE SOIL STRESS MEASURING CELLS IN LABORATORY APPLICATIONS INVOLVING STRESS REVERSALS, SOILS AND FOUNDATIONS, Vol: 50, Pages: 448-449, ISSN: 0038-0806
Jardine RJ, Zhu B, Foray P, et al., 2010, Experimental arrangements for investigation of soil stresses developed around a displacement pile, Soils and Foundations, Vol: 50, Pages: 447-448, ISSN: 0038-0806
Foray PY, Tsuha CHC, Silva M, et al., 2010, Stress paths measured around a cyclically loaded pile in a calibration chamber, 7th International Conference on Physical Modelling in Geotechnics (ICPMG), Publisher: CRC PRESS-TAYLOR & FRANCIS GROUP, Pages: 931-937
Nishimura S, Gens A, Olivella S, et al., 2009, An elastoplastic model for the thm analysis of freezing soils
By employing a combination of ice pressure, liquid pressure and total stress as state variables, a new thermoplastic constitutive model has been developed that encompasses frozen and unfrozen behaviour within a unified effective-stress-based framework. It has been incorporated into a fully coupled thermo-hydro-mechanical (THM) finite element formulation that considers freezing and thawing in water-saturated soils and applied to a large-scale pipeline frost heave test. © CIMNE.
Zhu B, Jardine RJ, Foray P, 2009, THE USE OF MINIATURE SOIL STRESS MEASURING CELLS IN LABORATORY APPLICATIONS INVOLVING STRESS REVERSALS, SOILS AND FOUNDATIONS, Vol: 49, Pages: 675-688, ISSN: 0038-0806
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