In the French concept of deep nuclear waste repositories,the galleries should be backfilled with excavated argillite after the site has been filled.Some additives like lime could be used to improve the mechanical char...In the French concept of deep nuclear waste repositories,the galleries should be backfilled with excavated argillite after the site has been filled.Some additives like lime could be used to improve the mechanical characteristics of the argillite.After thousands of years,the degradation of the concrete lining of the galleries will generate an alkaline solution（pH value 12） that will diffuse through the backfill.This study presents the effect of a saturated Ca（OH）_2 solution circulation through lime-treated sample at 60 ℃ for 3,6 and 12 months,respectively.The effect of such circulation on the lime-treated Manois argillite（MA） was assessed by petrographical examination coupled to image analysis and scanning electron microscopy（SEM） equipped with energy dispersive X-ray（EDX） analyser of soil pieces.The objective of this study is to make the link among the mineralogical transformations,the textural and mechanical changes produced in the compacted clayey soil as a consequence of the alkaline solution circulation.展开更多
In order to investigate the hydro-mechanical （HM） and chemical perturbations induced in an argillaceous formation by forced ventilation during the operational period of a nuclear waste repository, a specific experim...In order to investigate the hydro-mechanical （HM） and chemical perturbations induced in an argillaceous formation by forced ventilation during the operational period of a nuclear waste repository, a specific experiment has been performed in a tunnel, at Mont Terri Underground Research Laboratory （URL） in Switzerland. This experiment has been selected in the international project DECOVALEX for model vali- dation and the numerical simulation of this ventilation experiment （VE） is the object of the present paper. Since the argillaceous rock exhibits anisotropic properties, particular attention is given to the evaluation of the effects of various anisotropic features on the predicted results. In situ measurements such as relative humidity （RH）, global water mass extracted, pore water pressure, water content, and relative displace- ments are compared to predictions using both isotropic and anisotropic parameters. Water permeability anisotropy is shown to be the most influencing parameter by far, whereas in situ stress anisotropy has an effect only during the excavation phase. The anisotropy for mechanical parameterization has also some influence, in particular through HM couplings. These HM couplings have the potential to be very significant in terms of providing confidence in describing the experimental observation, and should be considered for further investigation.展开更多
文摘In the French concept of deep nuclear waste repositories,the galleries should be backfilled with excavated argillite after the site has been filled.Some additives like lime could be used to improve the mechanical characteristics of the argillite.After thousands of years,the degradation of the concrete lining of the galleries will generate an alkaline solution（pH value 12） that will diffuse through the backfill.This study presents the effect of a saturated Ca（OH）_2 solution circulation through lime-treated sample at 60 ℃ for 3,6 and 12 months,respectively.The effect of such circulation on the lime-treated Manois argillite（MA） was assessed by petrographical examination coupled to image analysis and scanning electron microscopy（SEM） equipped with energy dispersive X-ray（EDX） analyser of soil pieces.The objective of this study is to make the link among the mineralogical transformations,the textural and mechanical changes produced in the compacted clayey soil as a consequence of the alkaline solution circulation.
基金the context of the international DECOVALEX Project (DEmonstration of Coupled models and their VALidation against EXperiments)Quintessa Ltd. and University of Edinburgh were supported by the Nuclear Decommissioning Authority (NDA), UK+2 种基金CEA was supported by Institut de Radioprotection et de Sreté Nucléaire(IRSN)The Japan Atomic Energy Agency (JAEA) and the Institute of Rock and Soil Mechanics, Chinese Academy of Sciences (CAS)funded DECOVALEX and participated in the workEC project NF-PRO (Contract number FI6W-CT-2003-02389) under the coordination of ENRESA (Empresa Nacional de Residuos Radiactivos)
文摘In order to investigate the hydro-mechanical （HM） and chemical perturbations induced in an argillaceous formation by forced ventilation during the operational period of a nuclear waste repository, a specific experiment has been performed in a tunnel, at Mont Terri Underground Research Laboratory （URL） in Switzerland. This experiment has been selected in the international project DECOVALEX for model vali- dation and the numerical simulation of this ventilation experiment （VE） is the object of the present paper. Since the argillaceous rock exhibits anisotropic properties, particular attention is given to the evaluation of the effects of various anisotropic features on the predicted results. In situ measurements such as relative humidity （RH）, global water mass extracted, pore water pressure, water content, and relative displace- ments are compared to predictions using both isotropic and anisotropic parameters. Water permeability anisotropy is shown to be the most influencing parameter by far, whereas in situ stress anisotropy has an effect only during the excavation phase. The anisotropy for mechanical parameterization has also some influence, in particular through HM couplings. These HM couplings have the potential to be very significant in terms of providing confidence in describing the experimental observation, and should be considered for further investigation.
