References of "Collin, Frédéric"
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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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See detailBelgian clay geo-resources and their use for making compressed earth bricks
Mango-Itulamya, Lavie Arsène ULiege; Collin, Frédéric ULiege; Fagel, Nathalie ULiege

Conference (2018, September 14)

This study has two objectives: contribute to the knowledge of Belgian clays and evaluate their use for manufacture of compressed earth block (CEBs). Nineteen Belgian clays formations were sampled in 56 ... [more ▼]

This study has two objectives: contribute to the knowledge of Belgian clays and evaluate their use for manufacture of compressed earth block (CEBs). Nineteen Belgian clays formations were sampled in 56 sites and 135 samples were collected and analyzed. The analyzes focused on the determination of particle size, plasticity, nature and mineralogy, the main characteristics for assessing the suitability of the soil to make CEBs. These analyzes allow to classify the sampled formations in three categories: clays that can be used unchanged to make CEBs (2 formulations), clays that are suitable for the manufacture of CEBs but require modification (13 formulations) and clays that are unsuitable to the manufacture of CEBs (4 formulations). [less ▲]

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See detailBehavior of Laterally Loaded Piles: Effects of Soil and Interface Behaviors on P-Y Curves
Ahayan, Sanae ULiege; Panagiotis, Kotronis; Benjamin, Cerfontaine et al

Scientific conference (2018, June 27)

Monopiles have been by far the most common support structure for offshore turbines. They have always been an appropriate solution for complex site conditions. Design of monopiles is usually based on the ... [more ▼]

Monopiles have been by far the most common support structure for offshore turbines. They have always been an appropriate solution for complex site conditions. Design of monopiles is usually based on the use of nonlinear p-y curve. These curves are primordially based on the use of simple constitutive models for soil, such as Tresca criterion. Since soil behavior is highly non-linear and very complex, fundamental features of soil such as anisotropy, creep, or destructuration have to be taken into consideration. Accordingly, it is necessary to consider more complex soil behavior constitutive models. This work aims to explain, via FEM simulations, the influence of different constitutive laws for soil, on the laterally loaded pile responses. Tresca, Mohr-Coulomb criteria and Modified Cam-Clay model have been compared and their effect on p-y curve is analyzed. [less ▲]

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See detailRevalorization Of The Use Of Raw Earth In Construction Practices In Kinshasa (Democratic Republic of Congo)
Mango-Itulamya, Lavie Arsène ULiege; Fagel, Nathalie ULiege; Collin, Frédéric ULiege et al

in Wingert-Playdon, Kate (Ed.) Shaping the Quality of Life (2018, May 19)

Development is impossible without the realization of basic infrastructure and the construction of a quality habitat. Therefore, this project aims to contribute to the valuation of the clay resources of ... [more ▼]

Development is impossible without the realization of basic infrastructure and the construction of a quality habitat. Therefore, this project aims to contribute to the valuation of the clay resources of the Kinshasa region in order to develop the production of local, sustainable and energy efficient construction materials. The chosen region is justified by the abundance of clay raw materials and by important needs. The Kinshasa region is facing strong spatial and demographic expansion with, as consequence, the development of a suburban area in which the habitat quality is a critical problem. Since the early 1990 and the bankruptcy of the Kinshasa Brickyard, the abandonment of building in clay materials was systematic in Kinshasa. Nearly the whole population turned to a local material: the concrete brick. It is a brick made by manual or mechanical compression by mixing grinding fines of a sandstone rock (the Inkisi sandstone) locally called “dust”, alluvial sands (alluvial deposits of the Congo River or the Mbinza, Kalamu and Ndjili rivers) and cement. These concrete bricks of 10, 15 or 20 kilograms cost on average 1, 1.5 and 2 $ the brick. Despite this high cost for most households, the concrete brick architecture is almost the only present in Kinshasa. Earth bricks (even in terra-cotta) are considered poor materials and low resistance materials. People prefer big concrete bricks, which they consider to be more aesthetic and stronger. In addition, the lack of masons trained to build with other types of materials complicates the implementation of another construction method in the region. This is a challenge that seeks to overcome a brickyard which has just been created in the nearby province of the Central Congo. I have participated in providing solutions to that challenge. The brickyard tries to diversify its products by offering a compressed earth block (CEB) made on earth-sand and earth-sand-cement to suburban and disadvantaged populations. The idea is to put forward the ecological, economic and comfort benefits of earthen habitat. To achieve this, compressed earth blocks (CEB) were produced locally in Kinshasa by a manual press. The dimensions of the manufactured CEB have been adapted to be closer to those of concrete bricks. After a period of drying, the bricks were brought to a laboratory in Belgium to undergo durability tests (accelerated erosion test and accelerated aging test) and uniaxial compression test on CEB submitted to different rates of relative humidity. This work will show how we manage to generate interest among the local population about the use of earth brick based on scientific researches aiming to produce a quality building material. [less ▲]

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See detailModélisation hydromécanique de quelques problèmes de géotechnique dans le cadre des changements climatiques
Collin, Frédéric ULiege; Kotronis, Panagiotis; Ahayan, Sanae ULiege et al

Scientific conference (2018, February 21)

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See detailNumerical modelling of multiphysics couplings and the strain localization
Collin, Frédéric ULiege; Kotronis, Panagiotis; Pardoen, Benoit et al

Scientific conference (2018, February 01)

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See detailHydro-mechanical study of MAVL nuclear waste repository galleries in Callovo-Oxfordian claystone
Argilaga, Albert ULiege; Charlier, Robert ULiege; Cerfontaine, Benjamin ULiege et al

Conference (2018, February 01)

The disposal of radioactive waste in deep underground repositories has been studied for a long while (OECD/NEA, 1995). Argillaceous rocks have been found to be good candidates to host the repositories ... [more ▼]

The disposal of radioactive waste in deep underground repositories has been studied for a long while (OECD/NEA, 1995). Argillaceous rocks have been found to be good candidates to host the repositories because of their low permeability and the ability to absorb radionuclides. In France, the Callovo-Oxfordian argillite (COX) has been chosen by the national agency ANDRA to be the host rock to store the radioactive waste. During the previous years, the problem of gallery excavations in the COX host rock has been the case of study in Liège University. The problem, involving strain localization, is not well posed when modelled using classical theories; a microstructured model is proposed: local Second Gradient (Collin et al. 2006), this avoids the pathological mesh dependency by introducing an internal length that regularizes the problem. At the present time, the model takes into account several transverse anisotropies, e.g. cohesion (Pietruszczak et al. 2002), a visco-plastic model is retained to model the long term convergence, finally, a permeability evolution model allows to correlate strain localization and permeability increase (Pardoen et al. 2016). The purpose of this work is to model the long term behaviour of the MAVL galleries (100 years) with a special focus on the localisation extent, effect of ventilation, displacements and concrete stress state. Results (Figure 1) show an important effect of the supporting structure on the problem, the compressible wedges determine the localization mode by triggering the shear bands. Results also show a high sensitivity to the viscosity parameters. [less ▲]

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See detailCyclic and Fatigue Behaviour of Rock Materials: Review, Interpretation and Research Perspectives
Cerfontaine, Benjamin ULiege; Collin, Frédéric ULiege

in Rock Mechanics and Rock Engineering (2018), 51(2), 391-414

The purpose of this paper is to provide a comprehensive state of the art of fatigue and cyclic loading of natural rock materials. Papers published in the literature are classified and listed in order to ... [more ▼]

The purpose of this paper is to provide a comprehensive state of the art of fatigue and cyclic loading of natural rock materials. Papers published in the literature are classified and listed in order to ease bibliographical review, to gather data (sometimes contradictory) on classical experimental results and to analyse the main interpretation concepts. Their advantages and limitations are discussed, and perspectives for further work are highlighted. The first section summarises and defines the different experimental set-ups (type of loading, type of experiment) already applied to cyclic/fatigue investigation of rock materials. The papers are then listed based on these different definitions. Typical results are highlighted in next section. Fatigue/cyclic loading mainly results in accumulation of plastic deformation and/or damage cycle after cycle. A sample cyclically loaded at constant amplitude finally leads to failure even if the peak load is lower than its monotonic strength. This subcritical crack is due to a diffuse microfracturing and decohesion of the rock structure. The third section reviews and comments the concepts used to interpret the results. The fatigue limit and S–N curves are the most common concepts used to describe fatigue experiments. Results published from all papers are gathered into a single figure to highlight the tendency. Predicting the monotonic peak strength of a sample is found to be critical in order to compute accurate S–N curves. Finally, open questions are listed to provide a state of the art of grey areas in the understanding of fatigue mechanisms and challenges for the future. [less ▲]

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See detailNumerical Simulation with LAGAMINE for Coupled THM Mockup Test under Repository Relevant Loading Scenarios
Rawat, Abhishek; Baille, Wiebke; Collin, Frédéric ULiege

Conference (2018, January 31)

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See detailHydraulic behaviour of bentonite - Example of Application II
Collin, Frédéric ULiege; Dieudonné, Anne Catherine; Charlier, Robert ULiege

Scientific conference (2018, January)

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See detailHydraulic behaviour of bentonite - Introduction to the hydromechanical processes
Collin, Frédéric ULiege; Dieudonné, Anne Catherine; Charlier, Robert ULiege

Scientific conference (2018, January)

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See detailThe influence of clay composition and lithology on the industrial potential of earthenware
El Boudour El Idrissi, Hicham ULiege; Daoudi, Lahcen; El Ouahabi, Meriam ULiege et al

in Construction and Building Materials (2018)

This paper investigates the influence of clay composition and lithology on the industrial potential of earthenware. The 26 ceramic pastes collected were subjected to particle-size analysis, X-ray ... [more ▼]

This paper investigates the influence of clay composition and lithology on the industrial potential of earthenware. The 26 ceramic pastes collected were subjected to particle-size analysis, X-ray diffraction and X-ray fluorescence to investigate their compositions. The shards properties were determined through porosity tests, shrinkage, flexural and compressive strengths. Based on obtained results, all studied ceramic pastes turn out to offer a great potentiality for the earthenware industry despite their varied lithology. Argillite-based pastes exhibit the highest mechanical strengths while colluvium and schist-based pastes exhibit the lowest mechanical strengths. Further, the results have established a reference database for the perpetual restoration work of Marrakech monuments and can help to tracing back the source areas of the archaeological materials of this city. [less ▲]

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See detailComprehensive study of the drying behavior of Boom clay:Experimental investigation and numerical modeling
Hubert, Julien ULiege; Plougonven, Erwan ULiege; Prime, Noémie et al

in International Journal for Numerical and Analytical Methods in Geomechanics (2018)

This paper presents a thermo-hydro-mechanical framework to model the dryingbehavior of Boom clay. First, the experimental campaign conducted Noémie Primeis briefly presented because it is used to validate ... [more ▼]

This paper presents a thermo-hydro-mechanical framework to model the dryingbehavior of Boom clay. First, the experimental campaign conducted Noémie Primeis briefly presented because it is used to validate the model. The data acquisitionand processing is emphasized because of the use of X-ray microtomography to beable to more accurately compare experimental and numerical strain fields. The dif-ferent submodels are introduced. Numerical simulations are performed to illustratethe capability of the proposed model to reproduce the observed behavior. Finally,a comprehensive sensitivity study on several key model parameters associated withthe water retention curve, and the permeability of the medium, is performed to get abetter understanding of the physics behind the coupled model. [less ▲]

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See detailModelling the excavation damaged zone in Callovo-Oxfordian claystone using shear strain localisation
Pardoen, Benoit; Collin, Frédéric ULiege

Scientific conference (2017, November 27)

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