Numerical modelling of ground temperature evolution and soil subsidence as a result of underground coal fire

in Australian Geomechanics Journal (in press)

On micromechanical damage modeling in geomechanics: influence of numerical integration scheme

in International Journal of Computational & Applied Mathematics (2013), 246

Tunnel excavations in deep rocks provide stress perturbations which initiate diffuse and/or localized damage propagation in the material. This damage phenomenon can lead to significant irreversible ... [more ▼]

Tunnel excavations in deep rocks provide stress perturbations which initiate diffuse and/or localized damage propagation in the material. This damage phenomenon can lead to significant irreversible deformations and changes in rock properties. In this paper, we propose to model such behavior by considering a micromechanically-based damage approach. The resulting micromechanical model, which also accounts for initial stress, is described and assessed through the numerical analysis of a synthetic tunnel drilling in Opalinus Clay. A particular emphasis is put on the numerical integration of the model. In particular, an appropriate choice of the latter is required to ensure the numerical stability and a confident prediction of excavation damaged zone around tunnels. [less ▲]

A micro–macro approach of permeability evolution in rocks excavation damaged zones

in Computers & Geotechnics (2013), 49

Excavation damaged zone, with significant irreversible deformations and nonnegligible changes in flow and transport properties generally occurs in indurated clay around underground structures. The stress ... [more ▼]

Excavation damaged zone, with significant irreversible deformations and nonnegligible changes in flow and transport properties generally occurs in indurated clay around underground structures. The stress perturbation around the excavation could lead to a significant increase of the permeability physically due to diffuse and/or localized microcracks growth in the material. In the present study, we investigate microcracks-induced damage processes together with the subsequent modification in permeability. The proposed approach is based on a homogenization-based upper bound extended to the context of micro-cracked media in presence of initial stress. Application of this approach is done on a borehole excavation problem related to the Selfrac in situ experiments on Opalinus Clay. Although, the model fails to quan-titatively account for the in situ permeability change (which may also originated from existing macro-fractures), its prediction shows a significant evolution of the material permeability around the borehole. This is in qualitative agreement with available data. [less ▲]

Modelling the excavation damaged zone in Callovo-Oxfordian claystone with strain localization

Conference (2012, October)

Gallery excavation in clayey rocks induces stress perturbations that trigger damage propagation. The excavation process creates then the so-called excavation damaged zone in which properties are modified ... [more ▼]

Gallery excavation in clayey rocks induces stress perturbations that trigger damage propagation. The excavation process creates then the so-called excavation damaged zone in which properties are modified. The prediction of the extension and especially of the fracturing structure in this zone remains a crucial issue in the context of underground storage. Since strain localization in shear band mode is frequently observed in experimental works, the excavation damaged zone can be modeled by considering the development of strain localization bands. A hydro-mechanical modelling of a gallery excavation is performed. The numerical results exhibit an excavation damaged zone extension similar to the in situ measurements and provides information about the rock state within this zone. [less ▲]

Numerical study of the thermo-hydro-mechanical behavior of GMZ bentonite

Conference (2012, October)

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

Conference (2012, October)

Excavation damaged zone modelling in claystone with coupled second gradient model

in Yang (Ed.) Constitutive modeling of Geomaterials, Advances and applications (2012, October)

Galleries excavation leads to damage and significant properties changes of the host rock. The fracture structure of the excavation damaged zone created around the galleries remains nowadays a major issue ... [more ▼]

Galleries excavation leads to damage and significant properties changes of the host rock. The fracture structure of the excavation damaged zone created around the galleries remains nowadays a major issue especially in the context of underground storage. In order to correctly model the strain localisation, the second gradient local model (regularization method) is used within a hydro-mechanical modelling of a gallery excavation. The numerical results provide information about the strain localisation bands pattern. [less ▲]

Modèles de comportement thermo-hydromécaniques inclus dans le code aux éléments finis LAGAMINE de l’Université de Liège

Report (2012)

Hydromechanical analysis of fracturing in clayey rocks : modelling of disturbed argillite and ventilation test

Scientific conference (2012, February 15)

The present advances in hydro-mechanical analysis of a clayey rock fracturing are presented at a department seminar. The damaged zone existing around galleries composing underground structures is studied ... [more ▼]

The present advances in hydro-mechanical analysis of a clayey rock fracturing are presented at a department seminar. The damaged zone existing around galleries composing underground structures is studied through two aspects: rock-atmosphere interaction at gallery wall and rock fracturing modelling. These two aspects are discussed through the numerical results of an in situ ventilation test modelling and a biaxial compression test modelling. [less ▲]

Anisotropic hydromechancial modelling of HGA field-scale experiment in Opalinus Clay

Conference (2012)