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  • Journal article
    Burberry CM, Jackson CA-L, Cosgrove JC, 2011,

    Late Cretaceous to Recent deformation related to inherited structures and subsequent compression within the Persian Gulf: a 2D seismic case study

    , Journal of the Geological Society, Vol: 168, Pages: 485-498

    The Persian Gulf is part of an asymmetric foreland basin related to the Zagros Orogen. Few published studies of this basin and associated onshore areas include seismic reflection data. We present a seismic-stratigraphic interpretation based on marine 2D seismic data, which reveals the presence of two types of compressional structures within the basin: (1) faulted domes related to salt movement and the offshore trace of a NNE–SSW-trending dextral basement fault (the Kazerun Fault); (2) long-wavelength (16 km), low-amplitude (60 ms two-way travel time) folds relating to the advancing deformation front associated with the orogen. Thinning of age-constrained stratal units across structures related to the offshore trace of the Kazerun Fault implies a distinct pulse of uplift on this fault during the Maastrichtian. The geometry of growth strata across other intra-basin structures suggests a second, later stage of deformation, which began in the Middle Miocene. Thickening and folding of post-Middle Miocene stratal units towards the NE (i.e. towards the Zagros Orogen) is interpreted to reflect rapid loading, subsidence and compression related to southwestwards advance of the orogen. The results of this study have implications for the interaction between pre-existing structures and later compressional events both within the Persian Gulf and elsewhere.
  • Journal article
    Whittaker AC, Duller RA, Springett J, Smithells RA, Whitchurch AL, Allen PAet al., 2011,

    Decoding downstream trends in stratigraphic grain size as a function of tectonic subsidence and sediment supply

    , GEOLOGICAL SOCIETY OF AMERICA BULLETIN, Vol: 123, Pages: 1363-1382, ISSN: 0016-7606
  • Journal article
    Young NE, Briner JP, Stewart HAM, Axford Y, Csatho B, Rood DH, Finkel RCet al., 2011,

    Response of Jakobshavn Isbræ, Greenland, to Holocene climate change

    , Geology, Vol: 39, Pages: 131-134, ISSN: 0091-7613

    Rapid fluctuations in the velocity of Greenland Ice Sheet (GIS) outlet glaciers over the past decade have made it difficult to extrapolate ice-sheet change into the future. This significant short-term variability highlights the need for geologic records of preinstrumental GIS margin fluctuations in order to better predict future GIS response to climate change. Using 10Be surface exposure ages and radiocarbon-dated lake sediments, we constructed a detailed chronology of ice-margin fluctuations over the past 10 k.y. for Jakobshavn Isbræ, Greenland's largest outlet glacier. In addition, we present new estimates of corresponding local temperature changes using a continuous record of insect (Chironomidae) remains preserved in lake sediments. We find that following an early Holocene advance just prior to 8 ka, Jakobshavn Isbræ retreated rapidly at a rate of ~100 m yr-1, likely in response to increasing regional and local temperatures. Ice remained behind its present margin for ~7 k.y. during a warm period in the middle Holocene with sustained temperatures ~2 °C warmer than today, then the land-based margin advanced at least 2-4 km between A.D. 1500-1640 and A.D. 1850. The ice margin near Jakobshavn thus underwent large and rapid adjustments in response to relatively modest centennial-scale Holocene temperature changes, which may foreshadow GIS response to future warming. © 2011 Geological Society of America.
  • Journal article
    Rood DH, Burbank DW, Finkel RC, 2011,

    Spatiotemporal patterns of fault slip rates across the Central Sierra Nevada frontal fault zone

    , Earth and Planetary Science Letters, Vol: 301, Pages: 457-468, ISSN: 0012-821X

    Patterns in fault slip rates through time and space are examined across the transition from the Sierra Nevada to the Eastern California Shear Zone-Walker Lane belt. At each of four sites along the eastern Sierra Nevada frontal fault zone between 38 and 39° N latitude, geomorphic markers, such as glacial moraines and outwash terraces, are displaced by a suite of range-front normal faults. Using geomorphic mapping, surveying, and 10Be surface exposure dating, mean fault slip rates are defined, and by utilizing markers of different ages (generally, ~20ka and ~150ka), rates through time and interactions among multiple faults are examined over 104-105year timescales. At each site for which data are available for the last ~150ky, mean slip rates across the Sierra Nevada frontal fault zone have probably not varied by more than a factor of two over time spans equal to half of the total time interval (~20ky and ~150ky timescales): 0.3±0.1mm year-1 (mode and 95% CI) at both Buckeye Creek in the Bridgeport basin and Sonora Junction; and 0.4 +0.3/-0.1mm year-1 along the West Fork of the Carson River at Woodfords. Data permit rates that are relatively constant over the time scales examined. In contrast, slip rates are highly variable in space over the last ~20ky. Slip rates decrease by a factor of 3-5 northward over a distance of ~20km between the northern Mono Basin (1.3 +0.6/-0.3mm year-1 at Lundy Canyon site) to the Bridgeport Basin (0.3±0.1mm year-1). The 3-fold decrease in the slip rate on the Sierra Nevada frontal fault zone northward from Mono Basin is indicative of a change in the character of faulting north of the Mina Deflection as extension is transferred eastward onto normal faults between the Sierra Nevada and Walker Lane belt. A compilation of regional deformation rates reveals that the spatial pattern of extension rates changes along strike of the Eastern California Shear Zone-Walker Lane belt. South of the Mina Deflection, extension is accommoda
  • Journal article
    Turner SA, Liu JG, Cosgrove JW, 2011,

    Structural evolution of the Piqiang Fault Zone, NW Tarim Basin, China

    , JOURNAL OF ASIAN EARTH SCIENCES, Vol: 40, Pages: 394-402, ISSN: 1367-9120
  • Book chapter
    Gasparre A, Nishimura S, Minh NA, Coop MR, Jardine RJet al., 2011,

    The stiffness of natural London Clay

    , Pages: 81-95

    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.
  • Conference paper
    Zdravkovic L, Potts DM, St John HD, 2011,

    Modelling of a 3D excavation in finite element analysis

    , Pages: 319-335

    This paper investigates a number of issues related to the modelling of a retaining structure used to support an excavation in 3D finite element analyses. In particular, the effects of wall stiffness in different coordinate directions and the rotational fixity in the corner of the excavation are examined. Both square and rectangular excavations are analysed and compared with the equivalent axisymmetric and plane strain analyses, normally used as approximations for modelling purposes. The chosen geometry, construction sequence and soil conditions are based on a proposed deep excavation at Moorgate in London (next to the Moor House development), which will form part of an underground station for the Crossrail project. The objective of the study is to provide a detailed assessment of wall and ground movements and structural forces in the wall in the light of different modelling assumptions. The study has wider application to a variety of projects that include the development of infrastructure, the construction of deep basement car parks and buried structures, and the effect that these have on the surrounding areas.
  • Conference paper
    Nelson R, Piggott M, Wilson C, Kramer Set al., 2011,

    Compressible Flows on Adaptive and Unstructured Meshes with FLUIDITY

    , 6th International Conference on Fluid Mechanics, Publisher: AMER INST PHYSICS, ISSN: 0094-243X
  • Book chapter
    Gasparre A, Nishimura S, Coop MR, Jardine RJet al., 2011,

    The influence of structure on the behaviour of London Clay

    , Pages: 67-79

    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.
  • Conference paper
    Foray P, Tsuha C, Silva M, Jardine RJ, Yang ZX, Rimoy Set al., 2011,

    Soil-pile interaction on an instrumented pile under cyclic axial loads in sand

    , 5th International Conference on Earthquake Geotechnical Engineering
  • Journal article
    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
  • Conference paper
    Avgerinos V, Kontoe S, 2011,

    Modelling the ovalisation of circular tunnels due to seismic loading using different approaches

    , 5th International Conference on Earthquake Geotechnical Engineering
  • Conference paper
    Tripe R, Kontoe S, 2011,

    A numerical investigation into the interaction between topographic and soil layer amplification of earthquake motion

    , 5th International Conference on Earthquake Geotechnical Engineering, (5ICEGE)
  • Journal article
    Goes S, Capitanio FA, Morra G, Seton M, Giardini Det al., 2011,

    Signatures of downgoing plate-buoyancy driven subduction in Cenozoic plate motions

    , PHYSICS OF THE EARTH AND PLANETARY INTERIORS, Vol: 184, Pages: 1-13, ISSN: 0031-9201
  • Journal article
    Fang F, Pain CC, Navon IM, Gorman GJ, Piggott MD, Allison PAet al., 2011,

    The independent set perturbation adjoint method: A new method of differentiating mesh-based fluids models

    , International Journal for Numerical Methods in Fluids, Vol: In review
  • Journal article
    Sookhak Lari K, van Reeuwijk M, Maksimovic C, 2011,

    Combined bulk and wall reactions in turbulent pipe flow: decay coefficients and concentration profiles

    , J HYDROINF, Vol: 13, Pages: 324-333
  • Journal article
    Kumar M, Castro JM, Stafford PJ, Elghazouli AYet al., 2011,

    Influence of mean period ofground motion on the dynamic response of single and multi degree of freedom systems

    , Earthquake Engineering & Structural Dynamics, Vol: 3, Pages: 237-276
  • Journal article
    Mitchell AJ, Allison PA, Gorman GJ, Piggott MD, Pain CCet al., 2011,

    Tidal circulation in an ancient epicontinental sea: The Early Jurassic Laurasian Seaway

    , Geology, Vol: 39, Pages: 207-210, ISSN: 0091-7613
  • Journal article
    Kontoe S, Zdravkovic L, Potts DM, Menkiti COet al., 2011,

    On the relative merits of simple and advanced constitutive models in dynamic analysis of tunnels

    , Geotechnique, Vol: 61, Pages: 815-829, ISSN: 0016-8505

    This paper compares simple constitutive models that are widely used in engineering practice with more sophisticated methods in the context of a case study. In particular, four constitutive modelling approaches have been considered: a simple elasto-plastic constitutive model (modified Cam-clay), with and without Rayleigh damping; the same model coupled with a cyclic non-linear model that can simulate pre-yield hysteresis; and finally an advanced kinematic hardening model, which is an improved version of the Al-Tabbaa & Wood two-surface model. These four approaches are used to analyse the seismic response of a section of the Bolu tunnels during the 1999 Duzce earthquake. To shed light on the performance of the constitutive models, simple site response finite-element analyses were first undertaken for the studied site, paying particular attention to the calibration of the Rayleigh damping parameters. The results of these analyses, in terms of maximum shear strain, were then used as input to an analytical elastic method (extended Hoeg method) for calculating the thrust and bending moment acting in the tunnel lining. Finally the results of dynamic time domain plane-strain analyses, employing the four adopted constitutive modelling approaches, are compared against field observations and results obtained by the extended Hoeg method, to investigate the ability of the models, of ranging complexity, to mimic soil response under seismic excitation.
  • Journal article
    Haselwimmer CE, Riley TR, Liu JG, 2011,

    Lithologic mapping in the Oscar II Coast area, Graham Land, Antarctic Peninsula using ASTER data

    , INTERNATIONAL JOURNAL OF REMOTE SENSING, Vol: 32, Pages: 2013-2035, ISSN: 0143-1161

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