Geological and hydraulic characterisation of the excavation disturbed zone in the Opalinus Clay of the Mont Terri Rock Laboratory

Bossart, Paul; Meier, Peter; Moeri, Andreas; Trick, Thomas; Mayor, Juan Carlos

doi:10.1016/s0013-7952(01)00140-5

Cited by 283 publications

(168 citation statements)

References 6 publications

Supporting

Mentioning

157

Contrasting

Unclassified

Order By: Relevance

“…Distinct fracture patterns are observed around boreholes and galleries at the Mont Terri Underground Laboratory, depending on their orientation with respect to bedding and to the in situ stress field (Martin and Lanyon 2003, Bossart et al 2002. Bedding plane failure is found particularly prominent when the opening axis is oriented parallel to bedding.…”

Section: In Situ Observationsmentioning

confidence: 99%

Laboratory and In Situ Simulation Tests of the Excavation Damaged Zone Around Galleries in Opalinus Clay

Labiouse

Vietor

2013

Rock Mech Rock Eng

View full text Add to dashboard Cite

show abstract

Section: In Situ Observationsmentioning

confidence: 99%

Laboratory and In Situ Simulation Tests of the Excavation Damaged Zone Around Galleries in Opalinus Clay

Labiouse

Vietor

2013

Rock Mech Rock Eng

View full text Add to dashboard Cite

show abstract

“…Environmental impact zones around the underground facility are classified into an Excavation Damaged Zone (EDZ) near the tunnel and an Excavation disturbed Zone (EdZ) comprising the EDZ and areas around the excavations (Olsson and Winberg 1996;Bossart et al 2002;Tsang et al 2005). In an EDZ, mechanical and hydrogeological properties of the rock were intensely fractured during excavation, and the chemical properties were also modified by shotcrete, grouting, and air circulation.…”

Section: Resultsmentioning

confidence: 99%

Hydrochemical disturbances measured in groundwater during the construction and operation of a large-scale underground facility in deep crystalline rock in Japan

et al. 2015

View full text Add to dashboard Cite

Changes in the hydrochemical conditions of groundwater were evaluated following the construction of a large-scale underground facility at the Mizunami Underground Research Laboratory (MIU), Japan. The facility was constructed to a depth of 500 m in sedimentary and granitic rocks. Drawdown of the groundwater level in the range of several tens to hundreds of meters was observed up to hundreds of meters away from the shafts during the first ten years of facility construction and operation. Subsequent changes in groundwater chemistry occurred due to upconing of high-salinity groundwater from the deepest part of the shaft and the infiltration of low-salinity shallow groundwater. We predict that future deep groundwater chemistry in the vicinity of the MIU facility will resemble that of the present-day shallow groundwater. Multivariate statistical analysis provides fundamental insights into such a site. We found that the extent of hydrochemical variability related to MIU construction and operation was dependent on the distance from the facility shafts and galleries and on hydrogeological compartmentalization resulting from lithological boundaries (such as permeable conglomerates vs. more compact lithological units) and other features (such as faults or clay layers). We conclude that hydrochemical impact assessment of groundwater in low-permeability rock is essential prior to the construction of such a facility. This should include characterization of hydrogeological structures and compartments to propose suitable location of shafts and galleries.

show abstract

“…Permeability values in situ obtained within the sidewall of the borehole vary considerably and seem to depend on fracture density and interconnectivity [20]. Experimental observations show the presence of three zones around the borehole, in which unloading fractures are oriented parallel to the tunnel walls:…”

Section: Numerical Resultsmentioning

confidence: 99%

“…According to Bossart et al [20], this zone contains induced fractures caused by high deviatoric stresses close to tunnel wall and is characterized mainly by extensional failure parallel to the tunnel wall and reactivated bedding planes. This zone in Opalinus Clay at Mont Terri Rock Laboratory is supposed to extend for 0.5-1 tunnel radii from the excavation periphery [17,20]. In our case, it corresponds to around 5 cm.…”

Section: Numerical Resultsmentioning

confidence: 99%

“…Then, most fractures in the EDZ in indurated clays are directly caused by unloading induced by the short-term excavation (undrained elasto-plastic response) and are of extensional nature [18,19]. According to Bossart et al [20], EDZ shape around spherical excavation is slightly elliptical with vertical long axis and extends for 0.5-1 tunnel radii from the excavation periphery. (Fig.…”

Section: Opalinus Claymentioning

confidence: 99%

See 1 more Smart Citation

Hydro-mechanical modelling of the excavation damaged zone around an underground excavation at Mont Terri Rock Laboratory

Levasseur

Charlier

Frieg

et al. 2010

International Journal of Rock Mechanics and Mining Sciences

View full text Add to dashboard Cite

a b s t r a c tA zone with significant irreversible deformations and significant changes in flow and transport properties is expected to be formed around underground excavations in indurated clay. The stress perturbation around the excavation could lead to a significant increase of the permeability, related to diffuse and/or localised crack propagation in the material. The main objective of this study is to model these processes at large scale in order to assess their impacts on the performance of radioactive waste geological repositories. This paper concerns particularly the hydro-mechanical modelling of a long-term dilatometer experiment performed in Mont Terri Rock Laboratory in Switzerland. The proposed model defines the permeability as a function of the aperture of the cracks that are generated during the excavation. With this model, the permeability tensor becomes anisotropic. Advantages and drawbacks of this approach are described using the results of the Selfrac long-term dilatometer experiment.

show abstract

Geological and hydraulic characterisation of the excavation disturbed zone in the Opalinus Clay of the Mont Terri Rock Laboratory

Cited by 283 publications

References 6 publications

Laboratory and In Situ Simulation Tests of the Excavation Damaged Zone Around Galleries in Opalinus Clay

Laboratory and In Situ Simulation Tests of the Excavation Damaged Zone Around Galleries in Opalinus Clay

Hydrochemical disturbances measured in groundwater during the construction and operation of a large-scale underground facility in deep crystalline rock in Japan

Hydro-mechanical modelling of the excavation damaged zone around an underground excavation at Mont Terri Rock Laboratory

Contact Info

Product

Resources

About