The tunnel sealing experiment: An international study of full-scale seals

Martino, J.B.; Dixon, David A.; Kozak, E.T.; Gascoyne, M.; Vignal, B.; Sugita, Y.; Fujita, T.; Masumoto, Kazuhiko

doi:10.1016/j.pce.2006.04.023

Cited by 14 publications

(6 citation statements)

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“…The solid unit weight of the sand/bentonite mixture is 2.67 Mg/m 3 . The mixture used in this work is similar to that used in the full-scale "Tunnel Sealing Experiment" (TSX test) conducted in Canada (Martino et al 2007;Dixon et al 2007).…”

Section: Methodsmentioning

confidence: 99%

Determining the unsaturated hydraulic conductivity of a compacted sand–bentonite mixture under constant-volume and free-swell conditions

Cui¹,

Tang²,

Loiseau³

et al. 2008

Physics and Chemistry of the Earth, Parts A/B/C

173

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Highly compacted sand-bentonite mixtures are often considered as possible engineered barriers in deep high-level radioactive waste disposals. In-situ, the saturation of these barriers from their initially unsaturated state is a complex hydro-mechanical coupled process in which temperature effects also play a role. The key parameter of this process is the unsaturated hydraulic conductivity of the barrier. In this paper, isothermal infiltration experiments were conducted to determine the unsaturated hydraulic conductivity according to the instantaneous profile method. To do so, total suction changes were monitored at different locations along the soil specimen by using resistivity relative humidity probes. Three constant volume infiltration tests were conducted showing, unexpectedly, a decrease of the hydraulic conductivity during infiltration. One test performed under free-swell conditions showed the opposite and standard trend. These observations were interpreted in terms of microstructure changes during wetting, both under constant volume and free swell conditions.

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Section: Methodsmentioning

confidence: 99%

Determining the unsaturated hydraulic conductivity of a compacted sand–bentonite mixture under constant-volume and free-swell conditions

Cui¹,

Tang²,

Loiseau³

et al. 2008

Physics and Chemistry of the Earth, Parts A/B/C

173

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“…The isolated chamber C, one of the settings presented in this study, is a very useful tool which gives access to parameters on large scales, intermediate between the borehole and the regional scales. The experimental and numerical methods presented here for chamber C are also of interest in the design and validation of air‐ or water‐tight bulkhead, especially for underground waste repositories [ Martino et al ., ].…”

Section: Resultsmentioning

confidence: 99%

Field and numerical determinations of pneumatic flow parameters of unsaturated fractured porous rocks on various scales

Guillon

Vu²,

Pili

et al. 2013

Water Resources Research

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[1] Air permeability is measured in the fractured crystalline rocks of the Roselend Natural Laboratory (France). Single-hole pneumatic injection tests as well as differential barometric pressure monitoring are conducted on scales ranging from 1 to 50 m, in both shallow and deep boreholes, as well as in an isolated 60 m 3 chamber at 55 m depth. The field experiments are interpreted using numerical simulations in equivalent homogeneous porous media with their real 3-D geometry in order to estimate pneumatic parameters. For pneumatic injection tests, steady-state data first allow to estimate air permeability. Then, pressure recovery after a pneumatic injection test allows to estimate the air-filled porosity.Comparison between the various studied cases clarifies the influence of the boundary conditions on the accuracy of the often used 1-D estimate of air permeability. It also shows that permeabilities correlate slightly with fracture density. In the chamber, a 1 order-ofmagnitude difference is found between the air permeabilities obtained from pneumatic injection tests and from differential barometric pressure monitoring. This discrepancy is interpreted as a scale effect resulting from the approximation of the heterogeneous fractured rock by a homogeneous numerical model. The difference between the rock volumes investigated by pneumatic injection tests and by differential barometric pressure monitoring may also play a role. No clear dependence of air permeability on saturation has been found so far.Citation: Guillon, S., M. T. Vu, E. Pili, and P. M. Adler (2013), Field and numerical determinations of pneumatic flow parameters of unsaturated fractured porous rocks on various scales, Water Resour.

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“…By disregarding rockmass damage associated with the construction method employed, as it can be eliminated by taking necessary precautions [4,5], damage associated with stress changes, the excavation geometrical features, preexistent joints within the rockmass, and so on can be evaluated based on fracture coalescence [6] and divided into the highly damaged zone (HDZ), the excavation damage zone (EDZ), and the excavation influence zone (EIZ) [3].…”

Section: Introductionmentioning

confidence: 99%

The Numerical Simulation of Hard Rocks for Tunnelling Purposes at Great Depths: A Comparison between the Hybrid FDEM Method and Continuous Techniques

Vlachopoulos

Vazaios

2018

Advances in Civil Engineering

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Tunnelling processes lead to stress changes surrounding an underground opening resulting in the disturbance and potential damage of the surrounding ground. Especially, when it comes to hard rocks at great depths, the rockmass is more likely to respond in a brittle manner during the excavation. Continuum numerical modelling and discontinuum techniques have been employed in order to capture the complex nature of fracture initiation and propagation at low-confinement conditions surrounding an underground opening. In the present study, the hybrid finite-discrete element method (FDEM) is used and compared to techniques using the finite element method (FEM), in order to investigate the efficiency of these methods in simulating brittle fracturing. e numerical models are calibrated based on data and observations from the Underground Research Laboratory (URL) Test Tunnel, located in Manitoba, Canada. Following the comparison of these models, additional analyses are performed by integrating discrete fracture network (DFN) geometries in order to examine the effect of the explicit simulation of joints in brittle rockmasses. e results show that in both cases, the FDEM method is more capable of capturing the highly damaged zone (HDZ) and the excavation damaged zone (EDZ) compared to results of continuum numerical techniques in such excavations.

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The tunnel sealing experiment: An international study of full-scale seals

Cited by 14 publications

References 0 publications

Determining the unsaturated hydraulic conductivity of a compacted sand–bentonite mixture under constant-volume and free-swell conditions

Determining the unsaturated hydraulic conductivity of a compacted sand–bentonite mixture under constant-volume and free-swell conditions

Field and numerical determinations of pneumatic flow parameters of unsaturated fractured porous rocks on various scales

The Numerical Simulation of Hard Rocks for Tunnelling Purposes at Great Depths: A Comparison between the Hybrid FDEM Method and Continuous Techniques

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