Scientific conference in universities or research centers (Scientific conferences in universities or research centers)
Prediction of the excavation damaged zone in Callovo-Oxfordian claystone using a coupled second gradient model
Collin, Frédéric; Pardoen, Benoît
2015
 

Files


Full Text
Collin_abstract.pdf
Publisher postprint (107.8 kB)
Download
Annexes
AGS Newcastle_Collin_150723.pdf
Publisher postprint (6.58 MB)
Download

All documents in ORBi are protected by a user license.

Send to



Details



Abstract :
[en] The solution currently studied in France for long-term management of radioactive waste is the repository in deep argillaceous geological media with low permeability. The drilling of underground galleries in these clayey rocks induces damage propagation in the surrounding medium. This excavation process creates a damaged zone, in which the material properties are modified. The prediction of the fracture structure and material properties evolution within this zone is a major issue especially in the context of underground disposal. Experimental works have highlighted that the damage around galleries in Callovo-Oxfordian claystone is localized and develops mainly as extensional and shear fractures. We propose to model these shear fractures as a strain localisation process in the mode of a shear band. In order to properly represent the shear strain localisation behaviour, an enhanced model introducing a regularization method and an internal length scale is needed. Among the different regularization methods, the coupled second gradient local model is chosen. To illustrate the development of the damaged zone, a two-dimensional plane strain state hydro-mechanical modelling of a gallery excavation is performed (Lagamine code, ULg) for two orientations of the gallery in the Callovo-Oxfordian claystone. Firstly, a gallery oriented along the minor horizontal principal stress is considered. In this direction, the anisotropy of the stress state in the plane perpendicular to the gallery is the predominant factor leading to the elliptical shape of the damaged zone, with a significantly larger extent in the vertical direction. Secondly, a gallery oriented along the major horizontal principal stress is modelled. The stress state in the plane perpendicular to the gallery is quasi-isotropic and does not lead to shear strain localisation unless the material anisotropy is considered. Moreover, the modelling provides information about the fracture structure and evolution around the gallery. It exhibits a chevron fracture pattern corresponding to in situ experimental measurements of shear fractures for both considered gallery orientations.
Disciplines :
Civil engineering
Author, co-author :
Collin, Frédéric  ;  Université de Liège > Département ArGEnCo > Géotechnique
Pardoen, Benoît ;  Université de Liège > Département ArGEnCo > Géomécanique et géologie de l'ingénieur
Language :
English
Title :
Prediction of the excavation damaged zone in Callovo-Oxfordian claystone using a coupled second gradient model
Publication date :
23 July 2015
Event name :
AGS conference
Event organizer :
Australian Geomechanics Society
Event place :
Newcastle, Australia
Event date :
23 juillet 2015
Audience :
International
Funders :
F.R.S.-FNRS - Fonds de la Recherche Scientifique [BE]
Available on ORBi :
since 24 July 2015

Statistics


Number of views
77 (8 by ULiège)
Number of downloads
143 (6 by ULiège)

Bibliography


Similar publications



Contact ORBi