Response of Callovo-Oxfordian claystone during drying tests: unsaturated hydromechanical behavior

Guillon, Théophile; Giot, Richard; Giraud, Albert; Armand, Gilles

doi:10.1007/s11440-012-0172-9

Cited by 20 publications

(7 citation statements)

References 59 publications

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“…Callovo Oxfordian clay-rock samples with saline solution ([8, 9, 10]) and in situ on Tournemire * Institute of Engineering, Univ Grenoble Alpes clay-rock ( [11,12]) and on Callovo Oxfordian clay-rock ( [13]). Guillon et al [10] have performed static atmosphere drying tests which highlighted the hydro mechanical coupling and mechanical anisotropy of the samples. Both wetting and drying paths were explored, allowing the potential hysteretic behaviour of the samples.…”

Section: Many Authors Have Studied the Effect Of Drying And Wetting Cmentioning

confidence: 99%

Liquid water uptake in unconfined Callovo Oxfordian clay-rock studied with neutron and X-ray imaging

et al. 2018

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The Callovo Oxfordian clay-rock (COx) is studied in France for the disposal of radioactive waste, because of its extremely low permeability. This host rock is governed by a hydromechanical coupling of high complexity. This paper presents an experimental study into the mechanisms of water uptake in small, unconfined, prismatic specimens of COx, motivated by the comprehension of cracking observed during concrete/COx interface sample preparation. Water uptake is monitored using both x-ray tomography and neutron radiography, the combination of these imaging techniques allowing material deformation and water arrival to be quantified respectively. Given the speed of water entry and crack propagation, relatively fast imaging is required: 5 minute x-ray tomographies and ten-second neutron radiographies are used. In this study, pairs of similar COx samples from the same core are tested separately with each imaging technique. Two different orientations with respect to the core are also investigated. Analysis of the resulting images yields with micro-and macro-scale insights into hydro-mechanical mechanisms to be obtained. This allows the cracking to be interpreted as a rapid breakdown in capillary suction (supposed large both to drying and rebound from in-situ stress state) due to water arrival, which in turn causes a loss of effective stress, allowing cracks to propagate with ease, which in turn deliver water further into the material.

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Section: Many Authors Have Studied the Effect Of Drying And Wetting Cmentioning

confidence: 99%

Liquid water uptake in unconfined Callovo Oxfordian clay-rock studied with neutron and X-ray imaging

et al. 2018

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“…The water retention curve , also called the soil‐moisture characteristic curve, is a relationship between a soil's water content and water potential or between a soil's degree of saturation and the suction stress (Lu and Likos, 2004). It is used to predict the soil water storage in the mass balance equation, as well as to close the statement of the initial boundary‐value problem for coupled solid deformation–fluid flow (Borja, 2004; Borja et al, 2012a, 2012b, 2013b; Buscarnera and Nova, 2011; Buscarnera and di Prisco, 2011, 2012; Diamantopoulos and Durner, 2012; Ehlers et al, 2011; Garcia et al, 2011; Goumiri et al, 2012; Guillon et al, 2012; Le et al, 2012; Lloret‐Cabot et al, 2013; Mousavi Nezhad et al, 2011; Oostrom et al, 2012; Sun and Sun, 2012; Uzuoka and Borja, 2012; Zha et al, 2013). During the past few decades, the water retention curve for soils has been widely studied and is considered to be a fairly accurate representation of the water storage property under isothermal conditions, small deformation, monotonic loading, and even cyclic loading (Barquin‐Valle et al, 2011; Hassanizadeh et al, 2002; Horta et al, 2013; Manzanal et al, 2011; Mohammadi and Vanclooster, 2011; Tamagnini, 2004; Zhang, 2011).…”

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confidence: 99%

Finite Deformation and Fluid Flow in Unsaturated Soils with Random Heterogeneity

Song

Borja

2014

Vadose Zone Journal

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The first law of thermodynamics suggests an energy‐conjugate relationship among degree of saturation, suction stress, and density of an unsaturated porous material. Experimental evidence affirms that this constitutive relationship exists and that the water retention curves are dependent on the specific volume or density of the material. This constitutive feature must be incorporated into the mathematical formulation of boundary‐value problems involving finite deformation. We present a fully coupled hydromechanical formulation in the finite deformation range that incorporates the variation of degree of saturation with the Kirchhoff suction stress and the Jacobian determinant of the solid‐phase motion. A numerical simulation of solid deformation–fluid flow in unsaturated soil with randomly distributed density and degree of saturation demonstrates an intricate but well‐established coupling of the hydromechanical processes. As deformation localizes into a persistent shear band, we show that bifurcation of the hydromechanical response manifests itself not only in the form of a softening behavior but also through bifurcation of the state paths on the water‐retention surface.

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“…Sample are subjected to air with a control Relative Humidity and mass or/and strain changes are measured. Some devices rely on a static atmosphere with saline solution [10][11][12], other used complex system with a steam generator and a heating channel, in which air is blown through the chamber [13].…”

Section: Effect Of Desaturation/saturation Observed On Samplementioning

confidence: 99%

“…Guillon et al [10] have performed static atmosphere drying tests which highlighted the HM coupling and mechanical anisotropy of the samples. Both wetting and drying paths were explored, allowing the potential hysteretic behaviour of the samples.…”

Section: Effect Of Desaturation/saturation Observed On Samplementioning

confidence: 99%

Inputs from in situ experiments to the understanding of the unsaturated behaviour of Callovo-Oxfordian claystone

Armand¹,

Djizanne²,

Zghondi³

et al. 2016

E3S Web Conf.

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Abstract. The French national radioactive waste management agency (Andra) research program is dedicated to preparing the construction and operation of a deep geological disposal facility for high-level and intermediate-level long-lived radioactive waste (HL, IL-LLW) in the Callovo-Oxfordian claystone (COx). The characterization of the COx thermo-hydro-mechanical (THM) behavior, at different scales of interest, must gradually give relevant data for design and safety calculations. The effects of saturation and desaturation of COx claystone are studied in laboratory conditions (sample scale) and in situ (drift scale), in order to improve knowledge on ventilation effect at gallery wall as galleries will remains open during operational phase (more than 100 years for some specific galleries) in the repository. The Saturation Damaged Zone (SDZ) experiment is outlined and its results are discussed. This experimentation aims to change the relative humidity in an isolated portion of a gallery in order to follow the HM behavior of the surrounding rock mass. Drying and wetting cycles could induce in certain cases cracks and swelling and modify the hydromechanical behavior of the claystone around the gallery (Young modulus, strength, creep…). The long term behavior of the COx claystone at the vicinity of gallery is then studied by performing climatic, hydraulic, geological and geomechanical measurements. Results of the in situ experiment are discussed with respect to the identified process on samples. The discussion given on this paper intends to highlights the inputs from 7 years of an in situ experiment to better understand the unsaturated behavior of the COx claystone.

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Response of Callovo-Oxfordian claystone during drying tests: unsaturated hydromechanical behavior

Cited by 20 publications

References 59 publications

Liquid water uptake in unconfined Callovo Oxfordian clay-rock studied with neutron and X-ray imaging

Liquid water uptake in unconfined Callovo Oxfordian clay-rock studied with neutron and X-ray imaging

Finite Deformation and Fluid Flow in Unsaturated Soils with Random Heterogeneity

Inputs from in situ experiments to the understanding of the unsaturated behaviour of Callovo-Oxfordian claystone

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