The large-scale in situ PRACLAY heater test: First observations on the in situ thermo-hydro-mechanical behaviour of Boom Clay

Dizier, Arnaud; Chen, G.J.; Verstricht, Jan; Li, X.L.; Sillen, X.; Levasseur, Séverine

doi:10.1016/j.ijrmms.2020.104558

Cited by 15 publications

(4 citation statements)

References 13 publications

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“…[Fig. 1] For deep geological disposal, performance assessment of the host formation focused on isolating the HLW from the biosphere requires that in-situ experiments are complemented by numerical simulations to allow predictions of THM behaviour for extended periods of time (Armand et al, 2017;Chen et al, 2011aChen et al, , 2021De-Bruyn and Labat, 2002;Dizier et al, 2021;François et al, 2009;Selvadurai and Nguyen, 1997), or to allow investigating the effect of host rock degradation due to excavation (Nguyen et al, 2009;Pan et al, 2009;Perras and Diederichs, 2016;Rutqvist et al, 2009a). Mathematical models for such coupled geomechanical systems are often characterized by high dimensionality in which the associated computational cost becomes critical when dealing with inverse problems.…”

Section: Fundingmentioning

confidence: 99%

Using Reduced Basis Approximation for Efficient Surrogate-Based Inverse Identification of Thermo-Hydro-Mechanical Parameters from an In Situ Heating Test

et al. 2022

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In this paper, a reduced order model built from the reduced basis (RB) method is used as a surrogate for an inverse identification problem related to coupled thermo-hydro-mechanical (THM) processes. The RB space -spanned by solutions of the governing THM equations -is constructed using a greedy adaptive procedure guided by an a-posteriori error estimator that selects the optimal snapshot points in a given parametric space. The RB model is assessed in terms of accuracy and computational cost reduction for the three-dimensional transient coupled problem described by the ATLAS III small scale in-situ heating test. The substantial system size reduction and the associated significant computational gain result in a surrogate model suitable for parameter identification procedures in the Boom Clay material. The effectiveness of the proposed strategy is demonstrated by performing inverse analysis based on direct-search and genetic algorithm (GA) optimization supported by real sensor measurement data where 800 times faster computational speed-up was achieved.

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Section: Fundingmentioning

confidence: 99%

Using Reduced Basis Approximation for Efficient Surrogate-Based Inverse Identification of Thermo-Hydro-Mechanical Parameters from an In Situ Heating Test

et al. 2022

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“…The above behaviour may potentially alter the permeability of host rock as a result. To investigate the thermal effects on the THM behaviour of the host rock, some underground research laboratories (URL) have been already developing large scale in-situ heating tests, for instance in the HADES URF in Belgium (CER-BERUS, ATLAS and PRACLAY tests) (De Bruyn and Labat, 2002;Dizier et al, 2021), in the Mont Terri URL in Switzerland (HE-D test) (Jobmann and Polster, 2007;Garitte et al, 2017), and in the Meuse/Haute-Marne URL in France (TED, EPT, ALC1604, ALC1605 and CRQ tests) (Conil et al, 2020;Seyedi et al, 2021;Bumbieler et al, 2021;Armand et al, 2017;Narkuniene et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

Thermal Impact on the Excavation Damage Zone Around a Supported Drift Using the 2nd Gradient Model

2023

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The temperature increase induced by radioactive waste decay generates the thermal pressurisation around the excavation damage zone (EDZ), and the excess pore pressure could induce fracture re-opening and propagation. Shear strain localisation in band mode leading to the onset of micro/macro cracks can be always evidenced before the fracturing process from the lab experiments using advanced experimental devices, hence the thermal effects on the rock behaviour around the EDZ could be modelled with the consideration of development of shear bands. A coupled local 2 nd gradient model with regularisation technique is implemented, considering the thermo-hydro-mechanical (THM) couplings in order to well reproduce the shear bands. Furthermore, the thermo-poroelasticity framework is summarized to validate the implemented model. The discrepancy of thermal dilation coefficient between solid and fluid phases is proved to be the significant parameter leading to the excess pore pressure. Finally, an application of a heating test based on Eurad Hitec benchmark exercise with a drift supported by a liner is studied. The strain localisation induced by thermal effects is properly reproduced. The plasticity and shear bands evolutions are highlighted during the heating, and the shear bands are preferential to develop in the minor horizontal principal stress direction. Different shear band patterns are obtained with changing gap values between the drift wall and the liner. A smaller gap between the wall and the liner can limit the development of shear bands.

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“…The strategy proposed here takes advantage of the typical scenario for coupled THM problems in geomechanics, where the occurrence of plasticity is restricted to specific regions of small size with respect to the model size [51][52][53]. We divide the full domain into two sub-domains: an elastic region governed by linear THM equations and a region in which we may assume that the (evolving) plastic zone remains restricted spatially throughout the simulation, and which is governed by the nonlinear elasto-plastic constitutive law.…”

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confidence: 99%

Model order reduction of nonlinear thermo-hydro-mechanical systems by means of elastic and plastic domain sub-structuring

Larion,

Massart,

Díez

et al. 2024

Finite Elements in Analysis and Design

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The large-scale in situ PRACLAY heater test: First observations on the in situ thermo-hydro-mechanical behaviour of Boom Clay

Cited by 15 publications

References 13 publications

Using Reduced Basis Approximation for Efficient Surrogate-Based Inverse Identification of Thermo-Hydro-Mechanical Parameters from an In Situ Heating Test

Using Reduced Basis Approximation for Efficient Surrogate-Based Inverse Identification of Thermo-Hydro-Mechanical Parameters from an In Situ Heating Test

Thermal Impact on the Excavation Damage Zone Around a Supported Drift Using the 2nd Gradient Model

Model order reduction of nonlinear thermo-hydro-mechanical systems by means of elastic and plastic domain sub-structuring

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