References of "Collin, Frédéric"
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See detailHydro-mechanical behaviour of a pellets based bentonite seal: Numerical modelling of lab scale experiments
Gramegna, Liliana ULiege; Charlier, Robert ULiege; Collin, Frédéric ULiege

in Conference book (2020, October 19)

In most of the concept designs for nuclear waste disposals, bentonite-based materials are used to seal underground galleries and shafts. In order to assess the safety of such engineered barriers and to ... [more ▼]

In most of the concept designs for nuclear waste disposals, bentonite-based materials are used to seal underground galleries and shafts. In order to assess the safety of such engineered barriers and to provide a good prediction for the material behaviour, a number of experimental campaigns and constitutive models have been developed mainly focusing on bentonite compacted blocks. On the other hand, in recent years, the use of high density bentonite pellets combined with powdered bentonite has also been considered as an interesting alternative. The bentonite pellets mixtures present a prominent initial heterogeneity level as a result of the inter-pellets porosity, which evolves strongly during hydration. This paper aims to present the numerical modelling strategy adopted for a swelling pressure test on pellets mixture carried by CEA (France). Taking advantage of the finite element code LAGAMINE, the Barcelona Basic model is considered for the bentonite mechanical behaviour and the double porosity model proposed by [1] is used for the water retention behaviour and permeability evolution. Given the already-known complexity of the multiphysical and multiscale coupled processes taking place during bentonite-hydration, the obtained numerical results are in good agreement with experimental measurements. Especially, the non-monotonic evolution of the swelling pressure during the hydration phase is well captured by this model, which is always a challenge for this type of problem. [less ▲]

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See detailImprovement of lifetime of compressed earth blocks by adding limestone, sandstone and porphyry aggregates
Mango-Itulamya, Lavie Arsène ULiege; Collin, Frédéric ULiege; Fagel, Nathalie ULiege

in Journal of Building Engineering (2020), 29

This article studies the performance improvement of four properties, i.e. drying shrinkage, compressive strength, water absorption and abrasion resistance of Compressed Earth Blocks (CEB) by the addition ... [more ▼]

This article studies the performance improvement of four properties, i.e. drying shrinkage, compressive strength, water absorption and abrasion resistance of Compressed Earth Blocks (CEB) by the addition of 3 different types of aggregates (limestone, sandstone and porphyry). Five soils selected from Belgian active quarries were used. For each soil, the fabrication of CEB was done according to 5 formulations including 0%, 20%, 33%, 43% and 50% of aggregate addition (by volume). The addition of any aggregate decreases the drying shrinkage and water absorption of CEB. The different lithology of each aggregate did not influence the results. © 2019 [less ▲]

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See detailHydro-mechanical modelling of multiphase flow in naturally fractured coalbed using a multiscale approach
Bertrand, François ULiege; Buzzi, Olivier; Bésuelle, Pierre et al

in Journal of Natural Gas Science and Engineering (2020)

This paper presents a multiscale model developed for the modelling of multiphase flow in fractured reservoirs, particularly in coal seams during coalbed methane recovery (or carbon dioxide storage). The ... [more ▼]

This paper presents a multiscale model developed for the modelling of multiphase flow in fractured reservoirs, particularly in coal seams during coalbed methane recovery (or carbon dioxide storage). The variation of gas content in the matrix induces a shrinkage/swelling of the material which is likely to affect the fractures and thus the permeability of the rock. In addition, the permeability is also sensitive to the effective stress evolution. In order to simulate the reservoir production taking into account the cleat-scale phenomena on their specific length, a cleat-scale model is used for the modelling of the Representative Elementary Volume (REV at microscale). This cleat-scale model is integrated in a multiscale approach using the finite element square method. It consists to localize the macroscale deformation to the microscale by applying appropriate boundaries, then resolve the boundary value problem on the microscale with finite elements, then homogenize the microscale stresses with appropriate averages to compute macroscopic quantities, and finally resolve the boundary value problem on the macroscale with finite elements. This approach has the advantage that it does not require to write some constitutive laws at the macroscale but only at the REV-scale. The model is developed and implemented in a finite element code and then used for reservoir modelling. A synthetic case is first considered to demonstrate the ability of the model to obtain some bell-shape production curves as expected for unconventional reservoirs. Finally, a history matching exercise is carried out. [less ▲]

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See detailThe FE2 method: Multiscale hydro-mechanical modelling in the Lagamine code
Bertrand, François ULiege; Collin, Frédéric ULiege

Diverse speeche and writing (2019)

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See detailNumerical modelling of the E4 and E5 gas injection experiments
Corman, Gilles ULiege; Collin, Frédéric ULiege

Report (2019)

Nowadays, the deep geological disposal based on the multi-barriers confinement concept, is considered as one of the most promising solutions for the safe storage of radioactive wastes. Many Thermo-Hydro ... [more ▼]

Nowadays, the deep geological disposal based on the multi-barriers confinement concept, is considered as one of the most promising solutions for the safe storage of radioactive wastes. Many Thermo-Hydro-Mechanical (THM) phenomena are likely to occur during the construction and the lifetime of the repository, which could alter the confining function of the different constituent layers. Among these, the underground excavation process tends to create a so-called Excavation Damaged Zone (EDZ) in the surrounding of the storage galleries, where the mechanical and hydraulic properties are affected. For instance, the hydraulic permeability is increased compared to the sound rock formation. Moreover, during the exploitation of the system, a certain amount of gases, such as hydrogen could actually be generated in the nearfield of the repository due to the anoxic corrosion of the metal components, and lead to the alteration of the host rock behaviour. In light of this, the present work aims at developing a numerical tool within the finite element code LAGAMINE1, able to reproduce simultaneously the development of strain localisation bands due to excavation, the multiphysical couplings associated with gas generation and migrations, as well as their possible close interactions. This model includes on the one hand a THM part to describe triphasic porous media under unsaturated and non-isothermal conditions. On the other hand, since the problem involving strain localisation is not well posed when modelled using classical mechanics, the local second gradient approach is also integrated to the model. It helps avoiding the pathological mesh dependency by considering an enrichment of the continuum with microstructure effects through a regularizing internal length. This model is subsequently put into practise for the case of Boom Clay Formation, investigated by the Belgian National Radioactive Waste Management Agency (ONDRAF) to host a deep geological disposal. More particularly, two in situ gas injection tests conducted in two distinct directions in the Underground Research Laboratory (URL) in Mol, are simulated in 2D plane stain state. The modelling finally provides information about the fracture structure and permeability evolution due to the excavation, and about the stress state during a second phase of pore pressures stabilization, and a last phase of gas migrations. [less ▲]

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See detailStudy of the Behavior of Offshore Wind Turbine Monopiles under Monotonic and Cyclic Lateral Loading
Ahayan, Sanae ULiege; KOTRONIS, Panagiotis; YIN, Zhen-Yu et al

in Risk Evaluation and Climate Change Adaptation of Civil Engineering Infrastructures and Buildings (2019)

This chapter presents a study on the behavior of monopiles for offshore wind turbines under lateral loading, with a special focus on monopiles grounded in clayey soils. The behavior of the monopile is ... [more ▼]

This chapter presents a study on the behavior of monopiles for offshore wind turbines under lateral loading, with a special focus on monopiles grounded in clayey soils. The behavior of the monopile is studied in terms of soil reaction curve. The analysis focuses on three main points: under monotonic loading, we have analyzed the effect of the loading velocity on the response of the foundation. Simulations have clearly shown the influence of loading velocity on the behavior at the soil-pile interface. Then, based on an anisotropic constitutive law, the influence of both types of anisotropy (initial and induced by loading) has been studied. Finally, we have considered a nonalternating cyclic loading, in order to analyze the effect of cyclical accumulation on force-displacement curves of monopiles. [less ▲]

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See detailÉtude du comportement des monopieux des éoliennes offshore sous chargement latéral monotone et cyclique
Ahayan, Sanae ULiege; KOTRONIS, Panagiotis; YIN, Zhen-Yu et al

in Évaluation des risques et adaptation climatique d’ouvrages en génie civil et bâtiments est entré en productio (2019)

Ce chapitre présente une étude sur le comportement des monopieux des éoliennes offshore sous chargement latéral, avec un intérêt particulier pour les monopieux fondés dans les sols argileux. Le ... [more ▼]

Ce chapitre présente une étude sur le comportement des monopieux des éoliennes offshore sous chargement latéral, avec un intérêt particulier pour les monopieux fondés dans les sols argileux. Le comportement du monopieu est étudié en terme de courbe de réaction du sol. L’analyse se focalise sur trois points principaux: sous chargement monotone, nous avons analys´e l’effet de la vitesse de chargement sur la r´eponse de la fondation. Les simulations ont clairement montr´e l’influence de la vitesse de chargement sur le comportement `a l’interface sol-pieu. Ensuite, `a l’aide d’une loi de comportement anisotrope, l’influence des deux types d’anisotropie (initiale et induite par le chargement) a été étudiée. Enfin, nous avons considéré un chargement cyclique non alterné, afin d’analyser l’effet de l’accumulation cyclique sur les courbes force- déplacement des monopieux. [less ▲]

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See detailA 2nd gradient Thermo-Hydro-Mechanical model to investigate gas transfer processes in low-permeable media
Corman, Gilles ULiege; Collin, Frédéric ULiege

Poster (2019, September 30)

Nowadays, the deep geological disposal based on the multi-barriers confinement concept, is considered as one of the most promising solutions for the safe storage of radioactive wastes. Many Thermo-Hydro ... [more ▼]

Nowadays, the deep geological disposal based on the multi-barriers confinement concept, is considered as one of the most promising solutions for the safe storage of radioactive wastes. Many Thermo-Hydro-Mechanical (THM) phenomena are likely to occur during the construction and the lifetime of the repository, which could alter the confining function of the different constituent layers. Among these, the underground excavation process tends to create a so-called Excavation Damaged Zone (EDZ) in the surrounding of the storage galleries, where the mechanical and hydraulic properties are affected [1]. For instance, the hydraulic permeability is increased compared to the sound rock formation. Moreover, during the exploitation of the system, a certain amount of gases, such as hydrogen could actually be generated in the nearfield of the repository due to the anoxic corrosion of the metal components, and could potentially lead to the alteration of the host rock behaviour. In light of this, the present work aims at developing a numerical tool within the finite element code LAGAMINE, able to reproduce simultaneously the development of strain localisation bands due to excavation and the multiphysical couplings associated with gas generation and migrations. This model includes on the one hand a THM part [2] to describe triphasic porous media under unsaturated and non-isothermal conditions. On the other hand, since the problem involving strain localisation is not well posed when modelled using classical medium, the local second gradient approach [3] is also integrated to the model. It helps avoiding the pathological mesh dependency by considering an enrichment of the continuum with microstructure effects through a regularizing internal length [4]. This model is subsequently used for reproducing two in situ gas injection tests (Experiments E4 and E5 performed in the framework of the MEGAS European project in the Underground Research Laboratory (URL) in Mol [5]) conducted in two distinct directions in the Boom Clay Formation, which is investigated by the Belgian National Radioactive Waste Management Agency (ONDRAF) as potential host rock for a deep geological disposal. The 2D plain strain simulations provide information about the fracture structure and permeability evolution due to the excavation, and about the stress state during a phase of pore pressures stabilization, and during a last phase of gas migrations. [less ▲]

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See detailA numerical approach for the hydro-mechanical behaviour of bentonite seals in the context underground radioactive waste disposals
Gramegna, Liliana ULiege; Charlier, Robert ULiege; Collin, Frédéric ULiege

Poster (2019, June 04)

Deep geological disposals have been considered as a reasonable solution for the final management of high and medium-activity-level nuclear waste. The waste confinement is ensured by the host rock and/or ... [more ▼]

Deep geological disposals have been considered as a reasonable solution for the final management of high and medium-activity-level nuclear waste. The waste confinement is ensured by the host rock and/or engineered barrier. Bentonite is the main component of this barrier due to its very low permeability in saturated conditions and its swelling potential, namely swelling strain and swelling pressure development upon water saturation (respectively in unconstrained and constant volume conditions). In order to assess the long-term evolution of a geological repository, a good prediction of the hydromechanical response of bentonite subjected to various boundary conditions is needed. This is the main aim of BEACON project, which, among many other relevant objectives, promotes the development of an efficient European network between the most important agencies and universities involved in the nuclear waste disposals research. The objective of this work is to propose a new constitutive model able to reproduce the bentonite hydro-mechanical response. Based on advanced numerical methods, this model is implemented in the finite element code LAGAMINE. In this work, the Barcelona Basic Model is considered for the bentonite mechanical behaviour. Pressure dependence is taken into account for some mechanical parameters, as well as the dry density dependence that has also to be considered given the experimental evidences which link the final swelling strain (or stress) to the initial compaction state of the material. In parallel, the permeability evolution is analysed. Permeability is linked to pore structure of bentonite, in which it can be distinguished the volume inside the grains (microporosity), between the grains of clay (macroporosity) and, in the case of pellet-mixtures, between the pellets (megaporosity). The evolution during saturation of these porosities leads to the variation of the permeability. The developed model has been used for the numerical modelling of experimental tests proposed in the context of the BEACON project. The numerical results obtained are in good agreement with experimental measurements. Especially, the non-monotonic evolution of the swelling pressure during the hydration phase is well captured by this model, which is always a challenge for this type of problem. [less ▲]

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See detailEvaluation of Belgian clays for manufacturing compressed earth blocks
Mango-Itulamya, Lavie Arsène ULiege; Collin, Frédéric ULiege; Pilate, Pascal et al

in Geologica Belgica (2019), 22(3-4),

This study aims to characterize Belgian clays in order to evaluate their use for manufacture of compressed earth blocks (CEBs).

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See detailCleat-scale modelling of the coal permeability evolution due to sorption-induced strain
Bertrand, François ULiege; Buzzi, Olivier; Collin, Frédéric ULiege

in International Journal of Coal Geology (2019)

A model is developed at the scale of the fractures to take into account the hydromechanical couplings observed experimentally. It is implemented in the finite element code Lagamine. This numerical model ... [more ▼]

A model is developed at the scale of the fractures to take into account the hydromechanical couplings observed experimentally. It is implemented in the finite element code Lagamine. This numerical model is developed at the scale of the fractures and the matrix blocks. Fractures are modelled with interface elements specially adapted to manage sorption/desorption by taking into account the Langmuir’s isotherm. [less ▲]

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See detailRESORCINOL FORMALDEHYDE HYDROGEL DRYING BEHAVIOR: DESICCATION CRACKING MODELING
Hubert, Julien ULiege; Léonard, Angélique ULiege; Plougonven, Erwan ULiege et al

in Baressi, Antonello (Ed.) Proceedings of the 7th European Drying Conference (2019)

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See detailModelling of short-term interactions between concrete support and the excavated damage zone around galleries drilled in Callovo-Oxfordian claystone
Argilaga, Albert ULiege; Collin, Frédéric ULiege; Lacarrière, Laurie et al

in International Journal of Civil Engineering (2019)

Production of energy from nuclear power plants generates high-level radioactive nuclear waste, harmful during dozens of thousand years. Deep geological disposal of nuclear waste represents the most ... [more ▼]

Production of energy from nuclear power plants generates high-level radioactive nuclear waste, harmful during dozens of thousand years. Deep geological disposal of nuclear waste represents the most reliable solutions for its safe isolation. Confinement of radioactive wastes relies on the multi-barrier concept in which isolation is provided by a series of engineered (canister, backfill) and natural (host rock) barriers. Few underground research laboratories have been built all over the world to test and validate storage solutions. The underground drilling process of disposal drifts may generate cracks, fractures/strain localisation in shear bands within the rock surrounding the gallery especially in argillaceous rocks. These degradations affect the hydro-mechanical properties of the material, such as permeability, e.g. creating a preferential flow path for radionuclide migration. Hydraulic conductivity increase within this zone must remain limited to preserve the natural barrier. In addition galleries are currently reinforced by different types of concrete supports such as shotcrete and/or prefab elements. Their purpose is twofold: avoiding partial collapse of the tunnel during drilling operations and limiting convergence of the surrounding rock. Properties of both concrete and rock mass are time dependent, due to shotcrete hydration and hydromechanical couplings within the host rock. By the use of a hydro-mechanical coupled Finite Element Code with a Second Gradient regularization, this paper aims at investigating and predicting support and rock interactions (convergence, stress field). The effect of shotcrete hydration evolution, spraying time and use of compressible wedges is studied in order to determine their relative influence. [less ▲]

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See detailUsing a penalty term to deal with spurious oscillations in second gradient finite elements
Soufflet, Marc; Jouan, Gwendal; Kotronis, Panagiotis et al

in International Journal of Damage Mechanics (2019)

It is well known that it is necessary to introduce a length scale parameter in a continuum damage mechanics model to correctly simulate strain localization. The second gradient model, a special case of ... [more ▼]

It is well known that it is necessary to introduce a length scale parameter in a continuum damage mechanics model to correctly simulate strain localization. The second gradient model, a special case of kinematically enriched continua, considers an internal length parameter by taking into account the second order derivatives of the displacements in the virtual power principle. In this paper, we show that the original second gradient finite element of Chambon and co-workers can present spurious oscillations, especially for mode I crack propagation problems. After providing the plane stress second gradient constitutive law, we propose to add a penalty term in the original formulation in order to improve numerical convergence and to avoid spurious oscillations in the local variables distributions. Two numerical examples using classical damage mechanics laws, a three points reinforced concrete beam and a trapezoidal notched specimen are used to test the performance of the formulation. Parametrical studies are also shown on the influence of the penalty parameter. The problem of unrealistic damage spreading for damage values close to one, occurring often in mode I crack propagation problems, is finally discussed. [less ▲]

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See detailValorisation of soils from Kinshasa and Kongo Central regions (Democratic Republic of Congo) for raw earth bricks
Mango-Itulamya, Lavie Arsène ULiege; Pilate, Palcal; Collin, Frédéric ULiege et al

Conference (2018, December 07)

Soil is a building material widely used in Kinshasa and Kongo Central regions. Its exploitation is generally artisanal. Soils extracted are largely used for the manufacture of wood-fired bricks, with ... [more ▼]

Soil is a building material widely used in Kinshasa and Kongo Central regions. Its exploitation is generally artisanal. Soils extracted are largely used for the manufacture of wood-fired bricks, with consequent deforestation problems (Mango-Itulamya, 2015). In order to limit the production energy cost and to produce a sustainable building material, the use of raw earth bricks seems to be a solution. Six areas containing important soil deposits have been selected: Kinshasa, Mbanza Ngungu, Kasangulu, Nkamba, Kwilu Ngongo, and Lukala. Soils of these 6 zones were sampled and used to make raw earth bricks. [less ▲]

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