3867 resultaten

  • Nonlinear terms in storm surge predictions : effect of tide and shelf geometry with case study from hurricane Rita

    Auteurs: Lima Rego, J.R.; Li, C. (2010)
    Gepubliceerd in: Journal of geophysical research, C : oceans, volume 115 (2010), pagina 1019

    This study applied the finite volume coastal ocean model (FVCOM) to the storm surge induced by Hurricane Rita along the Louisiana - Texas coast. Peak water levels were shown to be lower than expected for a landfall at high tide. For low and high tide landfalls, nonlinear effects due to tide?surge coupling were constructive and destructive to total storm tide, respectively.

  • Lateral loading of pile foundations due to embankment construction

    Auteurs: Feddema, A.; Breedeveld, J.; Tol, A.F. van (2010)

    The objective of this research work was to gain a better understanding of the interaction between loads applied on the surface of soils, and the behaviour of adjacent long, vertical piles, embedded at depth in a stiff substratum. The influence of lateral thrust on the piles in an upper soft clay layer, due to simulated embankment construction, was examined and soil-pile interaction mechanisms were identified both for behaviour at working load and at the ultimate lateral capacity. The performance of a row of free headed piles and of a pile group were investigated experimentally in the geotechnical centrifuge (Deltares) for different pile and foundation geometries. Pile response, in terms of bending moment, deflection and lateral pressure, was determined for surcharge loads applied to the centrifuge model. This experimental database was used to calibrate a three dimensional finite element analysis of the same, simplified, model. These investigations led to the development of an approximate formula for lateral loading, based on the differential movement between the piles and the surrounding soil, which accounted for pile spacing. relative pile-soil stiffness and the degree of soil strength mobilisation. This loading function was incorporated in a computer program, SIMPLE, which calculated the pile bending moment and deflection profiles for flexible piles and pile groups. The algorithm was checked against the centrifuge model test results and the numerical analyses, and design charts were produced for free headed piles only_ Finally a design procedure was recommended for piled full-height bridge abutments and other facilities which feature passive lateral loading of piles by a nearby surcharge.

  • Influence of sand characteristics and scale on the piping process - experiments and multivariate analysis

    Auteurs: Beek, V.M. van; Knoeff, J.G.; Rietdijk, J.; Sellmeijer, J.B.; Lopez de la Cruz, J. (2009)

    The internal erosion of a sandy aquifer below a riverdike, a process called piping, is a dominant failuremechanism in the Netherlands.

  • On the dynamic elastoplastic material point method

    Auteurs: Vermeer, P.A.; Jassim, I.K. (2011)

    A dynamic Material Point Method for use in Geomechanics is presented.

  • Analytical and numerical analysis of tides and salinities in estuaries (part II) : salinity distributions in prismatic and convergent tidal channels

    Auteurs: Kuijper, C.; Rijn, L.C. van (2011)
    Gepubliceerd in: Ocean Dynamics, volume 61 (2011) nummer 11, pagina 1743-1765

    The analytical model described in this paper computes the maximum salinity distribution using the dispersion coefficient in the mouth as the only model parameter. The model has been calibrated using observational data in a large number of estuaries and experimental data in a tidal flume. The dispersion coefficient was succesfully related to geometric and hydrodynamic parameters resulting in an expression that can be used for convergent estuaries as well as prismatic channels.

  • Anisotropic creep model for soft soils : discussion

    Auteur: Haan, E.J. den (2010)
    Gepubliceerd in: Géotechnique, volume 60 (2010) nummer 12, pagina 963-966

  • Piled embankments, influence of installation and type of loading

    Auteurs: Bezuijen, A.; Eekelen, S.J.M. van; Duijnen, P.G. van (2010)

  • Characterization of a heterogeneous DNAPL source zone in the Borden aquifer using partitioning and interfacial tracers : residual morphologies and background sorption

    Auteur: Hartog, N. (2010)
    Gepubliceerd in: Journal of contaminant hydrology, volume 115 (2010) nummer 1-4, pagina 79-89

    Accurate assessment of the mass and spatial distribution of dense non-aqueous phase liquids (DNAPLs) in the subsurface is a prerequisite for efficient, cost-effective remediation of these persistent sources of groundwater contamination. A partitioning interwell tracer test (PITT) was performed in the Borden sand aquifer to characterize an aged heterogeneous DNAPL source zone. This zone evolved during 5 years of natural groundwater flow following the infiltration of 50 L chlorinated solvents DNAPL. To assess the lateral variability of remaining DNAPLmass andmorphology, four sweepzoneswere analyzed.

  • Estimating the depth of fresh and brackish groundwater in a predominantly saline region using geophysical and hydrological methods, Zeeland, the Netherlands

    Auteurs: Goes, B.J.M.; Oude Essink, G.H.P.; Vernes, R.W. (2009)

    In dit artikel worden meerdere geofysische methoden samengevoegd om de initiële zoet-zout verdeling in de Provincie zeeland te bepalen.

  • Modelling hyperconcentrated flow in the Yellow River

    Auteurs: Maren, D.S. van; Winterwerp, J.C. (2009)
    Gepubliceerd in: Earth surface processes and landforms : the journal of the British Geomorphological Research Group, volume 34 (2009) nummer 4, pagina 596-612

    A large amount of the total sediment load in the Chinese Yellow River is transported during hyperconcentrated floods. These floods are characterized by very high suspended sediment concentrations and rapid morphological changes withalternating sedimentation and erosion in the main channel, and persistent sedimentation on the floodplain. However, the physical mechanisms driving these hyperconcentrated floods are still poorly understood.

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