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See detailHydraulic studies for the Taoussa project, Mali
Erpicum, Sébastien ULg; Dewals, Benjamin ULg; Archambeau, Pierre ULg et al

in Proceedings of Africa 2013 conference (CD-Rom) (2013)

The Taoussa Project is a component of a large development scheme of the Niger River in the north-eastern part of Mali aiming at reducing desertification and improving socio-economic activity. It is mainly ... [more ▼]

The Taoussa Project is a component of a large development scheme of the Niger River in the north-eastern part of Mali aiming at reducing desertification and improving socio-economic activity. It is mainly made of a rockfill dam with central core around 18 m high and 1,000 m long across the valley of the Niger River, 130 km upstream of the town of Gao in the eastern part of Mali. The dam is equipped with a 25 MW hydroelectric power plant, a lock, a dock and a spillway. The spillway is made of a gated ogee crested weir divided into 10 bays and a downstream stilling basin, with a maximum discharge capacity of 3,100 m³/s. 210 km of high tension overhead cables and a 130 km long road complete the Project. The multipurpose Taoussa dam will enable the sustainable development of the Project area by securing water resources, increasing low-water level discharges downstream, creating a link between road and fluvial transports (dock) and producing electricity. The Ministère de l’Energie, des Mines et de l’Eau du Mali - Autorité pour l’Aménagement de Taoussa -commissioned Coyne et Bellier – Tractebel Engineering in 2006 to perform the detailed studies for the Project. In this framework, the hydraulic studies have been performed by the Laboratory of Engineering Hydraulics (HECE) of the University of Liege. These hydraulic studies, depicted in details in the paper, have been carried out successively by two complementary approaches: a first step realized on the basis of numerical modelling to study the flows at the scale of the reservoir and the river, and a second experimental investigation, using a scale model, to analyse in details the spillway operation conditions. They consider varied problems from large scale flow conditions in the reservoir during the spillway operation and hydrodynamic interactions between the dam, the lock and the hydroelectric power plant to validation and optimization of the hydraulic design and dimensions of the gated spillway and the stilling basin or release conditions downstream of the project structures, including the temporary derivation stage. [less ▲]

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See detailHydraulique Appliquée
Pirotton, Michel ULg; Archambeau, Pierre ULg; Erpicum, Sébastien ULg et al

Learning material (2007)

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See detailHydraulique Urbaine
Pirotton, Michel ULg; Archambeau, Pierre ULg; Erpicum, Sébastien ULg et al

Learning material (2008)

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See detailHydrea versus greffe de moelle osseuse
DRESSE, Marie-Françoise ULg

Conference (2003)

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See detailHydrichthys cyclothonis (Nov. Sp.), Hydroïde parasite du poisson Cyclothone signata (Garman)
Damas, Hubert ULg

in Bulletin du Musée royal d'histoire naturelle de Belgique = Mededelingen van het Koninklijk natuurhistorisch museum van België (1934), 10(7), 1-10

La croisière effectuée dans l'Atlantique, en 1922, par l'"Armauer Hansen", a procuré un lot important de poissons bathypélagiques. Cette collection comprend, entre autres, plus de 2000 exemplaires de ... [more ▼]

La croisière effectuée dans l'Atlantique, en 1922, par l'"Armauer Hansen", a procuré un lot important de poissons bathypélagiques. Cette collection comprend, entre autres, plus de 2000 exemplaires de Cyclothone signata (Garman). Quelques-uns de ces individus portent un hydroïde attaché à une des nageoires. Nous pensons que cette forme est nouvelle, bien qu'étroitement apparentée à d'autres hydroïdes (Hydrichthys mirus et boycei, Ichthyocodium sarcotretis) qui vivent également associés à des poissons. L'étude plus approfondie de nos spécimens nous a conduit à admettre que cet hydroïde est un véritable parasite et que sa sole basale digère les tissus de l'hôte. Ces faits nouveaux nous paraissent justifier cette courte note. [less ▲]

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See detailHydro and Hydro-Mechanical Modelling of Ventilation Test in Clayey Rocks
Pardoen, Benoît ULg; Talandier, Jean; Charlier, Robert ULg et al

in Mancuso, Claudio; Jommi, Cristina; D'Onza, Francesca (Eds.) Unsaturated Soils: Research and Applications (2012)

Hydro and hydro-mechanical numerical modellings are performed in order to acquire a better understanding of clayey rock behaviour and transfers occurring during an in situ ventilation test. The test is ... [more ▼]

Hydro and hydro-mechanical numerical modellings are performed in order to acquire a better understanding of clayey rock behaviour and transfers occurring during an in situ ventilation test. The test is performed in an experimental gallery that is part of an underground research laboratory. A biphasic flow model for unsaturated soil and an elasto-plastic constitutive law are used for the host formation. The models include exchange condition of fluid mass, anisotropy and the excavation damaged zone around the gallery. Finally, the ventilation test is reproduced and the model is calibrated based on the matching between numerical results and experimental measurements. [less ▲]

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See detailHydro and hydro-mechanical modelling of ventilation test in clayey rocks
Pardoen, Benoît ULg; Charlier, Robert ULg; Collin, Frédéric ULg et al

Poster (2011, October 03)

Long-term repository of radioactive waste in deep argillaceous geological media needs a good understanding of the host formation behaviour. Considering the safety function of the formation and the need of ... [more ▼]

Long-term repository of radioactive waste in deep argillaceous geological media needs a good understanding of the host formation behaviour. Considering the safety function of the formation and the need of low permeability, the behaviour of the excavation damaged zone (EDZ) is a major issue. Because drainage may modify the structure and the size of this zone, a ventilation test (SDZ) is realised by the French national radioactive waste management agency (ANDRA) in an experimental gallery of the Meuse/Haute-Marne underground research laboratory located in Callovo-Oxfordian claystone. The aim is to characterise the effect of the desaturation and possible resaturation of the damaged zone due to controlled ventilation. Numerical modellings are performed to reproduce the ventilation test. A biphasic flow model in unsaturated soil and an elasto-plastic constitutive law are used for the host formation. A nonclassical boundary condition has been developed in order to model the exchanges between the cavity and the rock. Numerical results show that it is possible to calibrate the models to obtain a satisfactory reproduction of the in situ experimental measurements and a better understanding of the fluid transfer around the gallery during the ventilation test. [less ▲]

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See detailHydro-mechanical analysis of the fracturing induced by the excavation of nuclear waste repository galleries using shear banding
Pardoen, Benoît ULg

Doctoral thesis (2015)

The long-term management of high-level nuclear wastes is envisaged by deep geological repository. Due to the safety function of the host formation, the behaviour of the Excavation Damaged Zone (EDZ) that ... [more ▼]

The long-term management of high-level nuclear wastes is envisaged by deep geological repository. Due to the safety function of the host formation, the behaviour of the Excavation Damaged Zone (EDZ) that develops around underground galleries during their drilling is of paramount importance. The EDZ is dominated by fracturing process which engenders irreversible modifications of the hydro-mechanical properties of the porous rock. In this zone, a significant hydraulic permeability increase of several orders of magnitude is observed. It may alter the safety function of the host formation by creating preferential flow paths for the migration of radionuclides towards the biosphere. Consequently, the understanding and the prediction of the EDZ hydro-mechanical behaviour are crucial issues for the long-term management of nuclear wastes. Among the different low-permeability media that are envisaged for the deep repository, the Callovo-Oxfordian claystone is studied. The fracturing behaviour, the water transfers, and the coupled processes that occur around the underground galleries are most particularly addressed, especially in the EDZ. The fractures induced by the excavation process are reproduced with strain localisation in shear bands. An appropriate model allowing to properly reproduce the strain localisation in geomaterials with finite element methods is used. It is an enhanced model for microstructure media called the coupled local second gradient model and which involves a regularisation method. Its application is extended to unsaturated anisotropic rocks with compressible solid grains. The numerical modelling of the fractured zone with shear banding provides information about its shape, extent, fracturing structure, and behaviour that are in good agreement with in situ measurements. In particular, the shape of the EDZ in the Callovo-Oxfordian claystone is governed by its anisotropy and the gallery convergence strongly depends on the appearance of the shear bands. The fluid transfers and the coupled processes are investigated in the EDZ. The impact of the rock fracturing on its hydraulic properties is addressed by taking into account strain localisation effects at macroscale. The evolution of the intrinsic water permeability is expressed by a strain-dependent relation which engenders a more pronounced increase of the permeability inside the shear bands. In agreement with experimental measurements, an important increase is reproduced in the excavation damaged zone. After gallery excavation, the hydraulic transfers in the rock surrounding the galleries are investigated by considering the interaction between the rock and the gallery air. These transfers are studied at large-scale during the reproduction of gallery air ventilation. Depending on the air hygrometry, the gallery ventilation implies drainage and desaturation of the surrounding rock which affect the shear banding development. The hydraulic transfers in the rock which depend on the water exchanges at gallery wall are also studied. The proposed approach aims to highlight the important hydro-mechanical aspects to take into account for the reproduction of the EDZ behaviour in unsaturated biphasic media with shear banding. The focus is resolutely on the large-scale numerical modelling of the EDZ as well as on the reproduction of the mechanical and hydraulic experimental measurements performed around galleries. [less ▲]

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See detailHydro-mechanical behavior of Boom clay host-rock in interaction with a deep excavated gallerys' lining
Salehnia, Fatemeh ULg; Li, Xiangling; Charlier, Robert ULg

in Alert workshop 2015-Booklet of abstracts (poster session) (2015)

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See detailHydro-mechanical behavior of fractures: 2D, F.E.M. modeling
Guiducci, Chiara; Pellegrino, Antonio; Radu, Jean-Pol ULg et al

in Auriault, J. L.; Geindreau, C.; Royer, P. (Eds.) Poromechanics II (2002)

A numerical approach for modeling the coupled hydro-mechanical fracture behavior is proposed. The movement of fluids through rock fractures and consequently the evolution of their hydraulic conductivity ... [more ▼]

A numerical approach for modeling the coupled hydro-mechanical fracture behavior is proposed. The movement of fluids through rock fractures and consequently the evolution of their hydraulic conductivity is an important subject in many petroleum related activities, mainly concerning the change of well productivity during the reservoir life. It is well known that the flow in the fractures is strongly controlled by the fracture apertures. Recent investigations on the distribution of the apertures in natural fractures suggest that the cubic law can, better than the Darcy law, predict the fluid flux through rough walled fractures as long as the appropriate average fracture aperture is used. A finite element code is developed to predict the influence that the stresses variation in the fracture has on the distributed hydraulic conductivity field. The proposed model combines the stochastic cubic law with a non-linear deformation function (hyperbolic) that is suggested to describe the stress-closure/opening curves of the joints and that allows to couple together the hydraulic and the mechanic fracture behavior. The relationships used and the validity of the present model are tested by means of the comparison between experimental data and numerical predictions (Bart 2000) in various bound-ary and loading conditions. Comparisons between the proposed new model and a no coupled one have also been performed. They show that the proposed coupled model allows for a more realistic description of the fracture behavior. [less ▲]

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See detailHYDRO-MECHANICAL COUPLING IN A FE 2 METHOD
van den Eijnden, Abraham Pieter ULg; Plua, Carlos; Bésuelle, Pierre et al

Scientific conference (2014, October 01)

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See detailHydro-mechanical modeling of damage due to underground excavation in hardened clay
Levasseur, Séverine ULg; Collin, Frédéric ULg; Frieg, Bernd et al

in Pietruszczak, Stan; Pande, Gyan; Tamagnini, Claudio (Eds.) et al Computational Geomechanics (2009)

A zone with significant irreversible processes and significant changes in flow and transport properties is expected to be formed after underground excavations. The perturbation of the excavation could ... [more ▼]

A zone with significant irreversible processes and significant changes in flow and transport properties is expected to be formed after underground excavations. The perturbation of the excavation could lead to a significant increase of the permeability, related to diffuse and/or localized crack proliferation in the material. The main objective of the study is to model these processes at large scale in order to assess their impacts on the performance of radioactive waste geological repositories. This paper concerns more particularly the hydro-mechanical modeling of a long term dilatometer experiment performed in Mont Terri Rock Laboratory in Switzerland. The proposed model defines the permeability as a function of the aperture of the cracks that are generated during the excavation. With this model, the permeability tensor becomes anisotropic. These developments are validated with the results of the experiment. [less ▲]

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See detailHydro-mechanical modelling of a coalbed methane production well via a dual-porosity approach
Bertrand, François ULg; Buzzi, Olivier; Collin, Frédéric ULg

in Book of Abstracts: 6th International Conference on Coupled THMC Processes in Geosystems (2017, July)

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See detailHydro-mechanical modelling of coalbed methane recovery
Bertrand, François ULg; Buzzi, Olivier; Cerfontaine, Benjamin ULg et al

Diverse speeche and writing (2017)

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See detailHydro-mechanical modelling of the development of preferential gas pathways in claystone
Gerard, Pierre ULg; Harrington, Jon; Charlier, Robert ULg et al

in Mancuso, Claudio; Jommmi, Cristina; D'Onza, Francesca (Eds.) Unsaturated Soils: Research and Applications (volume 2) (2012)

During long-term repository of radioactive waste in argillaceous formation, the gas migration in the host formation and in the engineered barriers is a crucial issue, because it could affect the safety ... [more ▼]

During long-term repository of radioactive waste in argillaceous formation, the gas migration in the host formation and in the engineered barriers is a crucial issue, because it could affect the safety function of the clay barriers. Gas migration tests on Callovo-Oxfordian argillite have been performed by the British Geological Survey. The observations show that gas migration is often accompa-nied by the development of preferential pathways, which propagate through the sample. Hydro-mechanical numerical modelling of these tests is performed. It ap-pears that a continuum approach to the movement of gas is not sufficient to repro-duce the experimental observations. A coupling between deformation of the me-dium, permeability and air entry pressure is proposed. The numerical results show that such coupling play an important role in a successful simulation of such gas flows. [less ▲]

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See detailHydro-mechanical modelling of the Excavation Damaged Zone around an underground excavation at Mont Terri Rock Laboratory
Levasseur, Séverine ULg; Charlier, Robert ULg; Frieg, Bernd et al

in International Journal of Rock Mechanics & Mining Sciences (2010), 47(3), 414-425

A zone with significant irreversible deformations and significant changes in flow and transport properties is expected to be formed in indurated clay around underground excavations. The stress ... [more ▼]

A zone with significant irreversible deformations and significant changes in flow and transport properties is expected to be formed in indurated clay around underground excavations. The stress perturbation around the excavation could lead to a significant increase of the permeability, related to diffuse and/or localized crack propagation in the material. The main objective of the study is to model these processes at large scale in order to assess their impacts on the performance of radioactive waste geological repositories. This paper concerns more particularly the hydro-mechanical modelling of a long term dilatometer experiment performed in Mont Terri Rock Laboratory in Switzerland within the Selfrac Project. The proposed model defines the permeability as a function of the aperture of the cracks that are generated during the excavation. With this model, the permeability tensor becomes anisotropic. Advantages and drawbacks of this approach are described thanks to the results of the Selfrac long term dilatometer experiment. [less ▲]

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See detailHydro-mechanical numerical modelling of geotechnical problems using local second gradient models
Chambon, René; Collin, Frédéric ULg

in Vermeer, Peter; Ehlers, W.; Herrmann, H. J. (Eds.) Modelling of cohesive-Frictional Materials (2004)

The paper presents some applications of a local second gradient theory used to describe the mechanical behavior of a continua. This theory has been developed in order to avoid some well known drawbacks of ... [more ▼]

The paper presents some applications of a local second gradient theory used to describe the mechanical behavior of a continua. This theory has been developed in order to avoid some well known drawbacks of classical theories, when softening and/or localization occur in a computation. This theory is extended and then applied in a hydromechanical coupled problem, in the case of fully saturated geomaterials. The corresponding finite element method taking into account the geometrical non linearities is detailed. Preliminary results using the finite element code developed in this context are then discussed and allow to study post localization behavior. [less ▲]

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See detailHydro-mechanical simulation in a deep excavation in Boom Clay
Hong, P.Y.; Cui, Y.J.; Pereira, J.M. et al

Poster (2015, March)

Detailed reference viewed: 29 (1 ULg)