References of "Cerfontaine, Benjamin"
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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 detailGuidelines related to the use of an existing cavity (mine/quarry) as reservoir of a pumped storage hydroelectric facility
Cerfontaine, Benjamin ULiege; Ronchi, Benedicta; Archambeau, Pierre ULiege et al

E-print/Working paper (2018)

Underground mines/quarries or open pits are manmade earthworks resulting from previous extraction of natural resources. They were mostly abandoned after resources depletion but underground or surface ... [more ▼]

Underground mines/quarries or open pits are manmade earthworks resulting from previous extraction of natural resources. They were mostly abandoned after resources depletion but underground or surface excavations remain. Pumped Storage Hydroelectricity (PSH) is one of the only efficient solutions for large scale energy storage. During peaks of energy production, water is pumped from a lower reservoir to an upper reservoir. On the other hand when demand peaks, energy is generated when water is transferred to the lower reservoir. The objective of this work is to study the recovering of abandoned excavation volumes as lower reservoirs for pumped storage hydroelectricity. Underground Pumped Storage Hydroelectricity (UPSH) is a particular case where at least one of the reservoir lies below the surface. Compare to classical PSH plants, using an existing cavity as a reservoir raises three main additional problems: 1) What are the water movements and thus discharge availability at the pump/turbine location depending on the reservoir (complex) geometry? 2) What are the exchanges between the reservoir (usually not watertight) and the surrounding medium? 3) How can the reservoir sides resist to cyclic loading imposed by the plant operation? In the following, some simplified criteria and issues are provided to carry out feasibility assessments of such rehabilitation projects, from the existing reservoir point of view. These criteria do no replace a detailed and complete study but draws the attention on problems specific to PSH using existing cavities as reservoir. They do not concern problems existing for every PSH project, such as location of electricity transport lines, availability of water… [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 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 detailOn the modelling of coupled hydro-mechanical behaviour of interfaces for offshore foundations
Cerfontaine, Benjamin ULiege; Collin, Frédéric ULiege

in Rasmussen, Amalie (Ed.) Marine Engineering: Emerging Developments and Global Challenges (2017)

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See detailValidation of a new elastoplastic constitutive model dedicated to the cyclic behaviour of brittle rock materials
Cerfontaine, Benjamin ULiege; Charlier, Robert ULiege; Collin, Frédéric ULiege et al

in Rock Mechanics and Rock Engineering (2017)

Old mines or caverns may be used as reservoirs for fuel/gas storage or in the context of large-scale energy storage. In the first case, oil or gas is stored on annual basis. In the second case pressure ... [more ▼]

Old mines or caverns may be used as reservoirs for fuel/gas storage or in the context of large-scale energy storage. In the first case, oil or gas is stored on annual basis. In the second case pressure due to water or compressed air varies on a daily basis or even faster. In both cases a cyclic loading on the cavern’s/mine’s walls must be considered for the design. The complexity of rockwork geometries or coupling with water flow requires finite element modelling and then a suitable constitutive law for the rock behaviour modelling. This paper presents and validates the formulation of a new constitutive law able to represent the inherently cyclic behaviour of rocks at low confinement. The main features of the behaviour evidenced by experiments in the literature depict a progressive degradation and strain of the material with the number of cycles. A constitutive law based on a boundary surface concept is developed. It represents the brittle failure of the material as well as its progressive degradation. Kinematic hardening of the yield surface allows the modelling of cycles. Isotropic softening on the cohesion variable leads to the progressive degradation of the rock strength. A limit surface is introduced and has a lower opening than the bounding surface. This surface describes the peak strength of the material andallows the modelling of a brittle behaviour. In addition a fatigue limit is introduced such that no cohesion degradation occurs if the stress state lies inside this surface. The model is validated against three different rock materials and types of experiments. Parameters of the constitutive laws are calibrated against uniaxial tests on Lorano marble, triaxial test on a sandstone and damage-controlled test on Lac du Bonnet granite. The model is shown to reproduce correctly experimental results, especially the evolution of strain with number of cycles. [less ▲]

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See detailLoi de comportement pour les argiles naturelles
Ahayan, Sanae ULiege; Cerfontaine, Benjamin ULiege; Collin, Frédéric ULiege

Conference (2017, May 23)

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

Diverse speeche and writing (2017)

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See detailEtude du comportement des Monopieux XL dans les sols argileux
Ahayan, Sanae ULiege; Cerfontaine, Benjamin ULiege; Kotronis, Panagiotis et al

Scientific conference (2017, February)

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See detailA fully coupled hydro-mechanical model for the modeling of coalbed methane recovery
Bertrand, François ULiege; Cerfontaine, Benjamin ULiege; Collin, Frédéric ULiege

in Journal of Natural Gas Science and Engineering (2017)

Most coal seams hold important quantities of methane which is recognized as a valuable energy resource. Coal reservoir is considered not conventional because methane is held adsorbed on the coal surface ... [more ▼]

Most coal seams hold important quantities of methane which is recognized as a valuable energy resource. Coal reservoir is considered not conventional because methane is held adsorbed on the coal surface. Coal is naturally fractured, it is a dual-porosity system made of matrix blocks and cleats (i.e fractures). In general, cleats are initially water saturated with the hydrostatic pressure maintaining the gas adsorbed in the coal matrix. Production of coalbed methane (CBM) first requires the mobilization of water in the cleats to reduce the reservoir pressure. Changes of coal properties during methane production are a critical issue in coalbed methane recovery. Indeed, any change of the cleat network will likely translate into modifications of the reservoir permeability. This work consists in the formulation of a consistent hydro-mechanical model for the CBM production modeling. Due to the particular structure of coal, the model is based on a dual-continuum approach to enrich the macroscale with microscale considerations. Shape factors are employed to take into account the geometry of the matrix blocks in the mass exchange between matrix and fractures. The hydro-mechanical model is fully coupled. For example, it captures the sorption-induced volumetric strain or the dependence of permeability on fracture aperture, which evolves with the stress state. The model is implemented in the finite element code Lagamine and is used for the modeling of one production well. A synthetic reservoir and then a real production case are considered. To date, attention has focused on a series of parametric analyses that can highlight the influence of the production scenario or key parameters related to the reservoir. [less ▲]

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See detailMAVL galleries in Callovo-Oxfordian claystone: analysis of the hydromechanical interaction using a continuum approach
Argilaga, Albert ULiege; Charlier, Robert ULiege; Cerfontaine, Benjamin ULiege et al

Conference (2017)

The disposal of radioactive waste in deep underground repositories has been studied for a long while (OECD/NEA, 1995). A multi-barrier solution ensures the isolation of the contaminants from the biosphere ... [more ▼]

The disposal of radioactive waste in deep underground repositories has been studied for a long while (OECD/NEA, 1995). A multi-barrier solution ensures the isolation of the contaminants from the biosphere. Argillaceous rocks are good candidates to host the repositories because of their low permeability and the ability to absorb radionuclides. In the case of France the Callovo-Oxfordian argillite (COX) has been chosen by the national agency ANDRA to be the host rock to store the radioactive waste of the country. During the previous years, the problem of gallery excavations in the COX host rock has been the case of study in Université de Liège; specially the simulation of the damaged zone (EDZ), which is created in the surrounding of the galleries during their excavation (Blümling et al. 2007). The problem, involving strain localization, is not well posed when modelled using classical mechanics theories; to overcome this, a microstructured model is used: 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 constitutive models for the COX take into account several transverse anisotropies: in situ stress state, elastic moduli, saturated permeability and plastic, this is achieved by the use of a fabric tensor that influences the cohesion (Pietruszczak et al. 2002). Classic elasto-plastic models like Drucker Prager and Van Eekelen, with cohesion softening, are appropriate to model the evolution of the EDZ, but they fail at reproducing the long term convergence of the gallery. To solve that, a visco-plastic model, independent from the plastic model, has been added. The permeability changes with the damage of the host rock, increasing several orders of magnitude in the EDZ. The latest developments of the model allowed taking this into account by linking the permeability of the material to the plastic deformation, which is sensibly higher inside the strain localization zone (Pardoen et al. 2016). The aforementioned model is used to evaluate the behaviour of the pillars between the galleries and, in particular, the evolution of the damage on those. The studied galleries concern the ones designed to host the medium activity long life waste (MAVL) with a diameter of 9-12m. The results of this work are intended to help to determine the optimal interaxis distance between the adjacent galleries. A series of parametric simulations at different interaxis distances are executed, in order to highlight the impact of the hydromechanical couplings on the EDZ evolution between the galleries. References: Blümling P, Bernier F, Lebon P, Martin CD (2007) The excavation damaged zone in clay formations time-dependent behaviour and influence on performance assessment. Phys Chem Earth 32(8–14):588– 599 Collin F, Chambon R, Charlier R (2006) A finite element method for poro mechanical modelling of geotechnical problems using local second gradient models. Int J Numer Meth Eng 65(11):1749–1772 OECD/NEA (1995). The environmental and ethical basis of geological disposal of longlived radioactive wastes. ïA collective opinion of the Radioactive Waste Management Committee of the OECD Nuclear Energy Agency. Technical report, OECD – Nuclear Energy Agency. Pardoen B, Talandier J, Collin F (2016), Permeability evolution and water transfer in the excavation damaged zone of a ventilated gallery, International Journal of Rock Mechanics and Mining Sciences 85, 192-208 Pietruszczak S, Lydzba D, Shao JF (2002) Modelling of inherent anisotropy in sedimentary rocks. Int J Solids Struct 39:637–648 [less ▲]

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See detailImplementation of an early age concrete model in LAGAMINE
Charlier, Robert ULiege; Collin, Frédéric ULiege; Argilaga Claramunt, Albert ULiege et al

Scientific conference (2017)

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See detailUnderground pumped hydro-energy storage in Wallonia (Belgium) using old mines – Potential and challenges
Erpicum, Sébastien ULiege; Archambeau, Pierre ULiege; Dewals, Benjamin ULiege et al

in Shaping the future of hydropower (2017)

Pumped Storage Hydroelectricity (PSH) is a well-known and efficient technology to store various amounts of electricity. In most parts of Europe, appropriate sites for new classical PSH plants are getting ... [more ▼]

Pumped Storage Hydroelectricity (PSH) is a well-known and efficient technology to store various amounts of electricity. In most parts of Europe, appropriate sites for new classical PSH plants are getting scarce. An alternative consists in using underground volumes as lower reservoirs to build so-called Underground Pumping Storage Hydroelectricity (UPSH) plants. The paper presents the main results of a research project currently investigating the potential and feasibility of such innovative plants in the context of Wallonia, where numerous abandoned mines and quarries are located all over the territory. After a description of the main types of reservoir configurations existing in the considered region and the evaluation of their expected energy storage potential, the tools and methodology developed in the scope of the project are presented. Their application to the case of an underground slates quarry and an open pit chalk mine helps in identifying the remaining challenges [less ▲]

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See detailHydromechanical modelling of interfaces
Dieudonné, Anne-Catherine; Cerfontaine, Benjamin ULiege

Conference (2016, September 21)

Detailed reference viewed: 27 (7 ULiège)