References of "Charlier, Robert"
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See detailTransversal action " Models " Phase 3 : Underground structure modelling
Pardoen, Benoît ULg; Collin, Frédéric ULg; Levasseur, Séverine ULg et al

Scientific conference (2014, April 09)

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See detailGas injection test in the Callovo-Oxfordian claystone: data analysis and numerical modelling
De la Vaissière, Rémi; Gerard, Pierre; Radu, Jean-Pol ULg et al

in Geological Society, London, Special Publications Online First (2014)

This paper describes a field-scale experiment on gas transport mechanisms performed at Andra’s Underground Research Laboratory (URL) in a clay rock. The experimental layout consists of two parallel ... [more ▼]

This paper describes a field-scale experiment on gas transport mechanisms performed at Andra’s Underground Research Laboratory (URL) in a clay rock. The experimental layout consists of two parallel boreholes that are equipped with multiple packer completions isolating three intervals each, which have been continuously monitoring the pore pressure evolution of the clay rock. Nitrogen gas was injected in the middle test interval of one of the boreholes at increasing rates. The entire gas test comprised six periods of controlled gas injections, each fol-lowed by a shut-in pressure recovery phase. The experimental data are presented along with their interpretation by means of numerical modelling of two-phase flow of gas and water using different numerical codes and different geometrical approaches that include axisymmetric, half-space and full 3D models. An iterative modelling process was used to show step-by-step how an accu-rate description of each component of the experiment system produced a satisfactory reproduc-tion of the experimental data and an improved understanding of the relevant phenomena. For instance, the initial volume of remaining water in the test interval, and the presence of a damaged zone around the boreholes, was important for the models to obtain good agreement with the field data. [less ▲]

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See detailHollow Cylinder Tests on Boom Clay: Modelling of Strain Localization in the Anisotropic Excavation Damaged Zone
François, B; Labiouse, V; Dizier, A et al

in Rock Mechanic and Rock Engineering (2014), 47(1), 71-86

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See detailExperimental arguments concerning a hydraulic connection layer during limestone convective drying
Prime, Noémie ULg; Housni, Z.; Fraikin, Laurent ULg et al

in Proceedings of the 6th International Conference on Unsaturated Soils, UNSAT 2014 (2014)

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See detailHydration kinetics of compacted low-density bentonite
Dieudonné, Anne-Catherine ULg; Romero, Enrique; Charlier, Robert ULg

in Khalili, Nasser; Russel, Adrian; Khoshghalb (Eds.) Unsaturated Soils: Research and Applications (2014)

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See detailInfluence of microfabric evolution on the retention behaviour of compacted clayey soils
Dieudonné, Anne-Catherine ULg; Della Vecchia, Gabriele; Charlier, Robert ULg et al

in Khalili, Nasser; Russel, Adrian; Khoshghalb, Arman (Eds.) Unsaturated Soils: Research and Applications (2014)

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See detailVertical transient loading of a suction caisson in dense sand
Cerfontaine, Benjamin ULg; Collin, Frédéric ULg; Charlier, Robert ULg

in Cerfontaine, Benjamin; Collin, Frédéric; Charlier, Robert (Eds.) 14th International Conference of the International Association for Computer Methods and Avances in Geomechanics (2014)

Suction caissons are hollow cylinders open towards the bottom currently used as anchors for deep water offshore facilities. They recently turned out to be advantageously exploited as foundation for ... [more ▼]

Suction caissons are hollow cylinders open towards the bottom currently used as anchors for deep water offshore facilities. They recently turned out to be advantageously exploited as foundation for offshore wind turbines in shallow water (Senders 2009). The Prevost model for cohesionless soils (Prevost 1985) is adapted for the modelling of their cyclic behaviour. It is able to reproduce plastic deformation in both loading and unloading, contractancy of the soil and pore pressure build up as well. In this paper, a fully-coupled transient axisymmetric analysis of a suction caisson is carried out. The monotonic partially drained behaviour of the caisson is firstly highlighted. Afterwards, pseudo-random and sinusoidal-equivalent storm signals are compared. Permanent displacements accumulated at the end of the storm show a good agreement between them but are slightly divergent, which indicates that the position of the extreme event might be a relevant issue. [less ▲]

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See detailAxisymmetric transient modelling of a suction caisson in dense sand
Cerfontaine, Benjamin ULg; Levasseur, Séverine ULg; Collin, Frédéric ULg et al

in Hicks, Michael A.; Brinkgreve, Ronald, B.J.; Rohe, Alexander (Eds.) Numerical Methods in Geotechnical Engineering (2014)

Suction caisson are hollow cylinders open towards the bottom that are currently used as anchors for deep water offshore facilities. They recently turned out to be advantageously exploited as foundation ... [more ▼]

Suction caisson are hollow cylinders open towards the bottom that are currently used as anchors for deep water offshore facilities. They recently turned out to be advantageously exploited as foundation for offshore wind turbines in shallow water (Senders 2009). The Prevost model for cohesionless soils (Prevost 1985) is currently used for the modelling of their cyclic behaviour. It’s able to reproduce plastic deformation in both loading and unloading, contractancy of the soil and pore pressure build up as well. In this paper, a fully- coupled transient axisymmetric analysis of a suction caisson is carried out. A vertical pseudo-random loading is transformed into equivalent ones. Comparison of the permanent displacement accumulated shows a good agreement between them. The influence of the interface conditions is also addressed. For low tension amplitude applied to the caisson, it can be modelled as “stuck” to the inner soil. However higher amplitude might lead to a total unplugging. [less ▲]

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See detailImplicit implementation of the Prevost model
Cerfontaine, Benjamin ULg; Charlier, Robert ULg

in Hicks, Michael A.; Brinkgreve, Ronald, R.J; Rohe, Alexander (Eds.) Numerical Methods in Geotechnical Engineering (2014)

The Prevost model for cohesionless soils (Prevost 1985) is currently used for the modelling of their cyclic behaviour, especially in earthquake engineering (Zerfa and Loret 2003) and (Yang and Elgamal ... [more ▼]

The Prevost model for cohesionless soils (Prevost 1985) is currently used for the modelling of their cyclic behaviour, especially in earthquake engineering (Zerfa and Loret 2003) and (Yang and Elgamal 2008). It’s made of conical yield surfaces that allow for plastic deformations in both loading and unloading. Its non-associated volumetric flow rule can roughly take into account pore pressure build-up and cyclic mobility. The method of implementation of a constitutive law is a crucial issue (Montáns and Caminero 2007) and (Mira et al. 2009). On one hand the accuracy of the solution must be ensured, especially when a large number of cycles are considered. But on the other hand, the cost of the computation must be minimized which implies step size as large as possible. In this paper, an implicit implementation of the Prevost model is proposed. The plastic flow rule is computed through a trapezoidal rule, at the time step n + 1/2, in order to increase the accuracy.An iterative process has to be solved, due to the implicit formulation.The Jacobian matrix of the internal Newton-Raphson process is computed analytically to enhance efficiency. The algorithm is implemented in the finite element code LAGAMINE that carries out fully-coupled analysis. Simulations of triaxial tests are compared with “exact” solution. [less ▲]

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See detailEvolution of clay fabric and water retention properties along hydromechanical stress paths
Dieudonné, Anne-Catherine ULg; Charlier, Robert ULg; Levasseur, Séverine ULg et al

in Numerical Methods in Geotechnical Engineering (2014)

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See detailModelling of localised gas preferential pathways in claystone
Gerard, Pierre; Harrington, Jon; Charlier, Robert ULg et al

in International Journal of Rock Mechanics & Mining Sciences (2014), 67

A long-term injection gas test on initially saturated claystone samples under isotropic confining pressure is modelled in a 2D hydro-mechanical framework, which includes the hydraulic anisotropy ... [more ▼]

A long-term injection gas test on initially saturated claystone samples under isotropic confining pressure is modelled in a 2D hydro-mechanical framework, which includes the hydraulic anisotropy. Evidences of localised pathways through the sample have been observed experimentally, which are difficult to reconcile with standard two-phaseflow models. The presence of an embedded pre-existing fracture is included in a continuum finite element model. A hydro-mechanical coupling between the fracture aperture, permeability and the retention properties along the fracture is included in the model. Due to the increase in permeability and the decrease of the air entry pressure induced by the rise in fluid pressure at constant mean total stress, the model provides good agreement with the experimental observations. The discussion offers additional insight into thefluidflow mechanisms into the sample and the processes involved in the development of localised gas pathways. This study allows conclusions to be drawn regarding the performance of the model and its practical limitations. [less ▲]

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See detailAn unsaturated hydro-mechanical modelling of two in-situ experiments in Callovo-Oxfordian argillite
Charlier, Robert ULg; Collin, Frédéric ULg; Pardoen, Benoît ULg et al

in Engineering Geology (2013), 165

The unsaturated behaviour of Callovo-Oxfordian argillite is investigated through the modelling of 2 in-situ experiments. The first test studies the influence of ventilation in a gallery on the hydro ... [more ▼]

The unsaturated behaviour of Callovo-Oxfordian argillite is investigated through the modelling of 2 in-situ experiments. The first test studies the influence of ventilation in a gallery on the hydro-mechanical behaviour of the rock mass. The second test consists in a gas injection in the rock mass from an experimental borehole. A hydro-mechanical model is described and used in the modelling of the experiments. A review of the main hydro-mechanical parameters of argillite is presented. The numerical results highlight the need of a flow boundary condition reproducing the fluid transfers between the surroundings and the rock mass. The influence of dissolved gas on the compressibility of the liquid phase is also emphasised. [less ▲]

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See detailDifferent phases of water transfer during rock drying
Prime, Noémie ULg; Housni, Zakarya; Fraikin, Laurent ULg et al

Conference (2013, September 10)

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See detailHeat and mass transfer coefficient analysis during rock convective drying
Prime, Noémie ULg; Housni, Zakarya; Fraikin, Laurent ULg et al

Conference (2013, August)

This paper presents some experimental investigations about convective drying of rocks. Cylindrical samples made of limestone are dried from one their bases submitted to an air flow, while the other ... [more ▼]

This paper presents some experimental investigations about convective drying of rocks. Cylindrical samples made of limestone are dried from one their bases submitted to an air flow, while the other surfaces are hermetically covered. All other factors being equal, the influence of two parameters is looked after: the cylinder height, equivalent to the volume/surface ratio of the samples, and the direction of the air flow. The tests are interpreted both from the drying curves and from the values of water and heat transfer coefficients. Results first highlight that air flow incidence on the dried surface changes the kinetics and the transfer coefficient values. It can thus be supposed that the air flow direction would modify the thickness of the transfer limit layer at the surface and/or would make invalid the hypothesis of such a limit layer model for some flow configurations. Besides, the volume/surface ratio is shown to be correlated to the evaporation flux on the constant drying phase, and thus to the transfer coefficients. Nonetheless, this link tends to disappear from sufficiently high values of the volume/surface ratio since, in this case, the transfer coefficients reach constant values. This effect, in addition to other observations made on the drying curves, well fits with the hypothesis of a hydraulically connected layer below the drying surface, which would maintain during the constant drying rate phase. In the present case, this layer would have a thickness of around 20 to 30 mm. [less ▲]

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See detailHydromechanical coupling theory in unsaturated geomaterials and its numerical integration
Charlier, Robert ULg; Radu, Jean-Pol ULg; Gerard, Pierre ULg et al

in Laloui, Lyesse (Ed.) Mechanics of Unsaturated Geomaterials (2013)

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