A large-scale gas injection test in the Meuse/Haute-Marne research laboratory: data analysis and numerical approach

Conference (2012, October)

Hydro and Hydro-Mechanical Modelling of Ventilation Test in Clayey Rocks

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 ▲]

Hydro and hydro-mechanical modelling of ventilation test in clayey rocks

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 ▲]

Avenant à la convention relative au développement des cartes géotechniques de Wallonie et des banques de données associées

Report (2010)

TIMODAZ report: Deliverable D13 – Simulation of lab and in situ tests

Report (2010)

HM modelling of in-situ gas injection tests in bentonite and argillite: the PGZ experiment

in Clays in Natural and Engineered Barriers for Radioactive Waste Confinement (2010)

Contribution to a jaw behavior and deformation study

Conference (2006, May)

Modelling chemo-hydro-mechanical behaviour of unsaturated clays: a feasibility study

in International Journal for Numerical and Analytical Methods in Geomechanics (2005), 29(9), 919-940

Effective capabilities of combined chemo-elasto-plastic and unsaturated soil models to simulate chemohydro-mechanical (CHM) behaviour of clays are examined in numerical simulations through selected ... [more ▼]

Effective capabilities of combined chemo-elasto-plastic and unsaturated soil models to simulate chemohydro-mechanical (CHM) behaviour of clays are examined in numerical simulations through selected boundary value problems. The objective is to investigate the feasibility of approaching such complex material behaviour numerically by combining two existing models. The chemo-mechanical effects are described using the concept of chemical softening consisting of reduction of the pre-consolidation pressure proposed originally by Hueckel (Can. Geotech. J. 1992; 29:1071-1086; Int. J. Numer. Anal. Methods Geomech. 1997; 21:43-72). An additional chemical softening mechanism is considered, consisting in a decrease of cohesion with an increase in contaminant concentration. The influence of partial saturation on the constitutive behaviour is modelled following Barcelona basic model (BBM) formulation (Geotech. 1990; 40(3):405-430; Can. Geotech. J. 1992; 29:1013-1032). The equilibrium equations combined with the CHM constitutive relations, and the governing equations for flow of fluids and contaminant transport, are solved numerically using finite element. The emphasis is laid on understanding the role that the individual chemical effects such as chemo-elastic swelling, or chemo-plastic consolidation, or finally, chemical loss of cohesion have in the overall response of the soil mass. The numerical problems analysed concern the chemical effects in response to wetting of a clay specimen with an organic liquid in rigid wall consolidometer, during biaxial loading up to failure, and in response to fresh water influx during tunnel excavation in swelling clay. Copyright (c) 2005 John Wiley [less ▲]

Numerical mdeling of hydro-mechanical fracture behaviour

Conference (2003)

A numerical approach for modeling coupled Hydro-Mechanical fracture behavior in 2D is presented in this paper. This approach accounts for the strong dependence of the flow characteristics on fracture ... [more ▼]

A numerical approach for modeling coupled Hydro-Mechanical fracture behavior in 2D is presented in this paper. This approach accounts for the strong dependence of the flow characteristics on fracture apertures and offers an anisotropic description of the flow propagation in the fracture. An interface finite element and a constitutive model are developed . In order to validate the applicability of the model to general geomechanic problems, 2D simulations were performed. Results show the good application of the mathematical model and the fundamental hydraulic role played by the fractures. [less ▲]

Numerical modeling of hydro-mechanical fracture behavior

in Pande, G. N.; Pietruszczak, S. (Eds.) Numerical models in Geomechanics (2002)

A numerical approach for modeling coupled hydro-mechanical fracture behavior is proposed. The movement of fluids through rock fractures is important in many engineering areas of practical interest such as ... [more ▼]

A numerical approach for modeling coupled hydro-mechanical fracture behavior is proposed. The movement of fluids through rock fractures is important in many engineering areas of practical interest such as those ones of petroleum and mining engineering. In that context, one of the most investigated and complex subjects is the effect on well productivity due to changes in hydraulic conductivity both on the matrix rock and on its main fractures. It is well known, that these flow characteristics are strongly controlled by 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 soil 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 through comparison between experimental data and numerical predictions (Bart 2000) in various boundary and loading conditions. Comparison between the Darcy model governing fluid flow equation and linear stress-closure/opening relation has also been performed showing the differences and the better de-scription given by the proposed new model. [less ▲]