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

Labiouse, V.; Vietor, Tim

doi:10.1007/s00603-013-0389-4

Cited by 88 publications

(43 citation statements)

References 11 publications

(11 reference statements)

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“…The experimental findings from thick-walled hollow cylinders of Opalinus Clay performed in the TIMODAZ project are presented and discussed in a companion paper (Labiouse and Vietor 2013).…”

Section: Hollow Cylinder Testingmentioning

confidence: 99%

Hollow Cylinder Simulation Experiments of Galleries in Boom Clay Formation

2013

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The rights are held by Springer-Verlag Wien.The final publication is available at http://link.springer.com. Abstract: In the context of nuclear waste disposal in clay formations, laboratory experiments were performed to study at reduced scale the Excavation Damaged Zone (EDZ) induced by the construction of galleries in the Boom Clay formation. For this purpose, thick-walled hollow cylindrical samples were subjected (after recovery of in-situ stress conditions) to a decrease of the inner confining pressure aiming at mimicking a gallery excavation. X-Ray computed Tomography (XRCT) scans of the specimens were carried out through the testing cell before and after the mechanical unloading and allowed to quantify the displacements undergone by the clay as a result of the mechanical unloading. The deformation of the hollow cylinders and the inferred extent of the damaged zone around the central hole are found to depend on the orientation of the specimen with respect to the bedding planes and show a great similarity with in-situ observations around galleries and boreholes at Mol URL in the Boom Clay formation. In the experiments performed on samples cored parallel to the bedding, the damaged zone is not symmetrical with respect to the hole axis and extends more in the direction parallel to the bedding. So it is for the radial convergence of the hole walls which is larger in the direction parallel to bedding than in the perpendicular one. On the contrary, a test on a sample cored perpendicularly to the bedding did not show any ovalisation of the central hole after the mechanical unloading. These observations confirm the significance of the pre-existing planes of weakness (bedding planes) in Boom Clay and the need for a correct consideration of the related mechanical anisotropy.

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“…The experimental findings from thick-walled hollow cylinders of Opalinus Clay performed in the TIMODAZ project are presented and discussed in a companion paper (Labiouse and Vietor 2013).…”

Section: Hollow Cylinder Testingmentioning

confidence: 99%

Hollow Cylinder Simulation Experiments of Galleries in Boom Clay Formation

2013

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“…As seen in Figure 6(c), cracks sub-parallel to the bedding plane opened, leading to a buckling failure in two areas that extend from the borehole in the direction normal to bedding (Labiouse and Vietor 2013). Another similar fracture pattern was found at large-scale around a gallery at Mont Terri URL as shown in Figure 6(d).…”

Section: Mechanical Anisotropy and Its Role In The Creation And Evolumentioning

confidence: 54%

“…After injecting a fluorescent resin and overcoring afterwards the injected borehole, sections of the core were saw-cut to study the damage around the borehole. As seen in Figure 6(a), the resin trace image presents a buckling fracture mode controlled by the bedding orientation (Labiouse and Vietor 2013). The removal of the dilatometer probe completely unloaded the borehole wall and the borehole collapsed.…”

Section: Mechanical Anisotropy and Its Role In The Creation And Evolumentioning

confidence: 96%

“…The difference in exhibited damage pattern most probably results from different failure modes: ductile behaviour in the Boom Clay (i.e. shear failure prevails along conjugated planes) and brittle behaviour in the Opalinus Clay (tensile failure along bedding planes and buckling) (Labiouse and Vietor 2013). Accounting for mechanical anisotropy and plasticity in the simulation of the hollow-cylinder tests on the Boom Clay enables a correct modelling of the convergence pattern (François et al 2013).…”

Section: Mechanical Anisotropy and Its Role In The Creation And Evolumentioning

confidence: 99%

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Consequences of the Thermal Transient on the Evolution of the Damaged Zone Around a Repository for Heat-Emitting High-Level Radioactive Waste in a Clay Formation: a Performance Assessment Perspective

Weetjens

Sillen

et al. 2013

Rock Mech Rock Eng

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The rights are held by Springer-Verlag Wien.The final publication is available at http://link.springer.com. Results from the TIMODAZ project indicate that the favourable properties of the clay host rock, which guarantee the effectiveness of the safety functions of the repository system, are expected to be maintained after the heating-cooling cycle. Hence, the basic assumptions usually made in PA calculations so far are expected to remain valid, and the performance of the system should not be affected in a negative way by the thermal evolution of the DZ around a radioactive waste repository in clay host rock.

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“…Such processes must be considered in interaction with the dissipation of pore water pressure induced by the draining gallery. Hard clays tend to show bedding plane splitting and buckling around the gallery while in more plastic clays (like in Boom Clay, the formation studied in this work) , the observed failure mechanisms around the tunnel consist essentially in pure shear failure, leading to conjugated shear fractures (Blümling et al 2007;Labiouse and Vietor, 2013). The zone in which major hydro-mechanical modifications occur is called the Excavation Damaged Zone (EDZ) Tsang et al 2005).…”

Section: Introductionmentioning

confidence: 94%

Hollow Cylinder Tests on Boom Clay: Modelling of Strain Localization in the Anisotropic Excavation Damaged Zone

et al. 2012

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The rights are held by Springer-Verlag Wien.The final publication is available at http://link.springer.com. ABSTRACTBoom Clay is extensively studied as a potential candidate to host underground nuclear waste disposal in Belgium. To guarantee the safety of such a disposal, the mechanical behaviour of the clay during gallery excavation must be properly predicted. In that purpose, a hollow cylinder experiment on BoomClay has been designed to reproduce, in a small-scale test, the Excavation Damaged Zone (EDZ) as experienced during the excavation of a disposal gallery in the underground. In this paper, the focus is

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

Abstract: The rights are held by Springer-Verlag Wien.The final publication is available at http://link.springer.com.

Cited by 88 publications

References 11 publications

Hollow Cylinder Simulation Experiments of Galleries in Boom Clay Formation

Hollow Cylinder Simulation Experiments of Galleries in Boom Clay Formation

Consequences of the Thermal Transient on the Evolution of the Damaged Zone Around a Repository for Heat-Emitting High-Level Radioactive Waste in a Clay Formation: a Performance Assessment Perspective

Hollow Cylinder Tests on Boom Clay: Modelling of Strain Localization in the Anisotropic Excavation Damaged Zone

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