References of "Levasseur, Séverine"
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See detailDrying induced shrinkage of Boom Clay: an experimental investigation
Prime, Noémie; Levasseur, Séverine ULg; Miny, Laurent et al

in Canadian Geotechnical Journal (2016), 53(3), 396-409

Drying induced shrinkage of geomaterials may have a strong effect on geostructure stability and deformation. Settlement of foundations, fracture opening on slopes, roads, tunnel walls may be due to drying ... [more ▼]

Drying induced shrinkage of geomaterials may have a strong effect on geostructure stability and deformation. Settlement of foundations, fracture opening on slopes, roads, tunnel walls may be due to drying shrinkage. However, there is still a lack of knowledge concerning shrinkage evolution in time and shrinkage propagation within the material. In this study, the shrinkage of a specific clayey rock, Boom Clay, under drying conditions is experimentally investigated. This rock is a deep geological formation which is under study for high-level and long-life radioactive waste storage in Belgium. Two experimental campaigns are here presented. The first one, based on vapour equilibrium drying technique and completed by sample size manual measurement, aims to characterize the material shrinkage in balanced states. The second one, based on convective drying technique completed by shape monitoring using X-ray tomography, aims to analyse how shrinkage develops before reaching a steady state. Both approaches put in evidence the shrinkage anisotropy of this structurally bedded rock, with a ratio around 2 between the direction of maximum strains and the direction of minimum strains. However, the two drying techniques also provide complementary results, as the relation between the amount of shrinkage and the retention curve (for the uniform drying imposed with saline solutions) and the kinetics of shrinkage propagation inside the material (for the non-uniform drying imposed with air convection). [less ▲]

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See detailUsing shear strain localisation to model the fracturing around gallery in unsaturated Callovo-Oxfordian claystone
Pardoen, Benoît ULg; Levasseur, Séverine ULg; Collin, Frédéric ULg

in Chau, Kam Tim; Zhao, Jidong (Eds.) Bifurcation and Degradation of Geomaterials in the New Millennium (2015, January 28)

Galleries drilling leads to damage propagation, fracturing and properties modifications in the surrounding medium. The prediction of the damaged zone behaviour is an important matter and needs to be ... [more ▼]

Galleries drilling leads to damage propagation, fracturing and properties modifications in the surrounding medium. The prediction of the damaged zone behaviour is an important matter and needs to be properly assessed. To do so the fractures can be modelled using shear strain localisation. The coupled local second gradient model is used under unsaturated conditions to correctly model the strain localisation behaviour. The permeability evolution and the rock desaturation due to air ventilation in galleries are considered. Finally, a hydro-mechanical modelling of a gallery excavation in Callovo-Oxfordian claystone is performed leading to a fairly good representation of the damaged zone. [less ▲]

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See detailOn Water Transfer and Hydraulic Connection Layer During the Convective Drying of Rigid Porous Material
Prime, Noémie; Housni, Z; Fraikin, Laurent ULg et al

in Transport in Porous Media (2015), 106(1), 47-72

The convective drying of a natural porous material, limestone, is investigated in this study, with both experimental and numerical approaches. The first experimental campaign, which focuses on the ... [more ▼]

The convective drying of a natural porous material, limestone, is investigated in this study, with both experimental and numerical approaches. The first experimental campaign, which focuses on the influence of samples’ slenderness, suggests the presence of a hydraulic connection layer between the porous water and the external environment, in spite of the very fine pore structure of the material. This hydraulic transfer enables the fast water evaporation at the beginning of the drying test, when external conditions drive the kinetics. Furthermore, the results show that this layer does not exceed 30 mm deep from the external surface, given the drying conditions of the test. A second experimental campaign aims to analyse, by mean of an X-ray tomography tool, the internal water content during the drying. It confirms that water transfer takes place within the limestone in two distinct stages. The first stage being faster than the second one with a homogeneous desaturation along the sample, it is consistent with the hypothesis of the hydraulic connection layer. Finally, the finite element modelling makes possible to identify the main mechanisms of water transfer, namely liquid convection and vapour diffusion. © 2014, Springer Science+Business Media Dordrecht [less ▲]

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See detailExperimental Investigation of Hydromechanical Coupling During Clay Drying
Prime, Noémie; Fraikin, Laurent ULg; Léonard, Angélique ULg et al

in Drying Technology (2015), 33(15-16), 1821-1829

Boom clay is studied as a potential host rock for underground nuclear waste storage. This experimental work analyzes its response under the convective drying conditions that may be applied in case of ... [more ▼]

Boom clay is studied as a potential host rock for underground nuclear waste storage. This experimental work analyzes its response under the convective drying conditions that may be applied in case of contact with the ambient atmosphere (during disposal drilling, for instance) or with gallery ventilation (because of damage in gallery lining). The drying kinetics is first established. In a second phase, the cracking and shrinkage onset and development are focused on, thanks to an X-ray microtomography device. The results show a phase of ideal shrinkage and a phase of shrinkage with desaturation, which are closely related to the kinetics. Cracking and shrinkage progressively develop from the drying surface, up to values representing about 3 and 12% of the cross section area, respectively. [less ▲]

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See detailUsing local second gradient model and shear strain localisation to model the excavation damaged zone in unsaturated claystone
Pardoen, Benoît ULg; Levasseur, Séverine ULg; Collin, Frédéric ULg

in Rock Mechanics & Rock Engineering (2015), 48(2), 691-714

The drilling of galleries induces damage propagation in the surrounding medium and creates, around them, the excavation damaged zone (EDZ). The prediction of the extension and fracture structure of this ... [more ▼]

The drilling of galleries induces damage propagation in the surrounding medium and creates, around them, the excavation damaged zone (EDZ). The prediction of the extension and fracture structure of this zone remains a major issue, especially in the context of underground nuclear waste storage. Experimental studies on geomaterials indicate that localised deformation in shear band mode usually appears prior to fractures. Thus, the excavation damaged zone can be modelled by considering the development of shear strain localisation bands. In the classical finite element framework, strain localisation suffers a mesh-dependency problem. Therefore, an enhanced model with a regularisation method is required to correctly model the strain localisation behaviour. Among the existing methods, we choose the coupled local second gradient model. We extend it to unsaturated conditions and we include the solid grain compressibility. Furthermore, air ventilation inside underground galleries engenders a rock– atmosphere interaction that could influence the damaged zone. This interaction has to be investigated in order to predict the damaged zone behaviour. Finally, a hydromechanical modelling of a gallery excavation in claystone is presented and leads to a fairly good representation of the EDZ. The main objectives of this study are to model the fractures by considering shear strain localisation bands, and to investigate if an isotropic model accurately reproduces the in situ measurements. The numerical results provide information about the damaged zone extension, structure and behaviour that are in very good agreement with in situ measurements and observations. For instance, the strain localisation bands that develop in chevron pattern during the excavation and rock desaturation, due to air ventilation, are observed close to the gallery. [less ▲]

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See detailExcavation damaged zone modelling including hydraulic permeability evolution in unsaturated argilaceous rock
Pardoen, Benoît ULg; Levasseur, Séverine ULg; Collin, Frédéric ULg

in Khalili, Nasser; Russell, Adrian R.; Khoshghalb, Arman (Eds.) Unsaturated Soils: Research & Applications (2014, July)

The drilling of galleries induces damage propagation in the surrounding medium and creates the Excavation Damaged Zone (EDZ) in which the material properties are modified. The prediction of the fracture ... [more ▼]

The drilling of galleries induces damage propagation in the surrounding medium and creates the Excavation Damaged Zone (EDZ) in which the material properties are modified. The prediction of the fracture structure and flow properties evolution within this zone are major issues especially in the context of underground nuclear waste storage. Since experimental results indicate that shear strain localisation appears prior to fractures, we model the EDZ with strain localisation in shear band mode using the coupled local second gradient model. The evolution of the intrinsic hydraulic permeability inside the fractures is taken into consideration as well as the influence of gallery ventilation on the rock desaturation. The numerical results provide information about the damaged zone extension, structure and behaviour with good correspondence to in situ measurements and observations. [less ▲]

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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 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 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 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 detailNumerical modelling of the excavated damaged zone in Boom Clay
Salehnia, Fatemeh ULg; Charlier, Robert ULg; Levasseur, Séverine ULg

in International Workshop on Geomechanics and Energy 2013 (2013, November 26)

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See detailBack Analysis and optimisation method with Lagamine
Levasseur, Séverine ULg; Bouffioux, Chantal ULg

Speech/Talk (2013)

Comparison of Back Analysis and Optimization Methods to characterize materials with LAGAMINE

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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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