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Thermal cycling: impact on bentonite permeability

Published online by Cambridge University Press:  02 January 2018

S. G. Zihms  and
J. F. Harrington
S. G. Zihms*
Affiliation:
British Geological Survey, Transport Properties Research Laboratory, Nicker Hill, Keyworth NG12 5GG, UK
J. F. Harrington*
Affiliation:
British Geological Survey, Transport Properties Research Laboratory, Nicker Hill, Keyworth NG12 5GG, UK
*
# Current Address: The Institute for Petroleum Engineering, Heriot-Watt University, Edinburgh EH14 4AS, UK
*E-mail: [email protected]
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Abstract

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Due to its favourable properties, in particular, low permeability and swelling capacity, bentonite has been favoured as an engineered-barrier and backfill material for the geological storage of radioactive waste. To ensure its safe long-term performance it is important to understand any changes in these properties when the material is subject to heat-emitting waste. As such, this study investigates the hydraulic response of bentonite under multi-step thermal loading subject to a constant-volume boundary condition, to represent a barrier system used in a crystalline or other hard-rock host rock. The experimental set up allows continuous measurement of the hydraulic and mechanical responses during each phase of the thermal cycle. After the initial hydration of the bentonite, the temperature was raised in 20°C increments from 20 to 80°C followed by a final step to reach 120°C. Each temperature was held constant for at least 7–10 days to allow the hydraulic transients to equilibrate. The data suggest that the permeability of bentonite appears to be sensitive to changes in temperature which may extend beyond those explained by simple changes in water viscosity. However, permeability may be boundary-condition dependent and this should be considered when designing experiments or applying these results to other repository host rocks. Either way, the magnitude of the change in permeability observed in this study is minor and its impact on the hydraulic performance of the barrier is negligible.

Keywords

bentonitepermeabilitythermal cyclingtemperaturehydraulic
Type
Research Article
Information
Mineralogical Magazine , Volume 79 , Issue 6 , November 2015 , pp. 1543 - 1550
Creative Commons
Creative Common License - CCCreative Common License - BY
Copyright © The Mineralogical Society of Great Britain and Ireland 2015. This is an open access article, distributed under the terms of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2015

References

Bucher, F., Müller-Vonmoos, M. (1989) Bentonite as containment barrier for the disposal of highly radioactive wastes. Applied Clay Science, 4, 157–177.CrossRefGoogle Scholar
Chen, G.J., Sillen, X., Verstricht, J. and Li, X.L. (2011) ATLAS III in situ heating test in boom clay: Field data, observation and interpretation. Computers and Geotechnics, 38, 683–696.CrossRefGoogle Scholar
Cho, W.J., Lee, J.O. and Chun, K.S. (1999) The temperature effects on hydraulic conductivity of compacted bentonite. Applied Clay Science, 14, 47–58.CrossRefGoogle Scholar
Cui, Y.-J. and Tang, A.M. (2013) On the chemo-thermo-hydro-mechanical behaviour of geological and engineered barriers. Journal of Rock Mechanics and Geotechnical Engineering, 5, 169–178.CrossRefGoogle Scholar
Cui, YI, Delage, P., Le, T.T., Li, X.L. and Tang, A.M. (2009) Investigating the time-dependent behaviour of Boom clay under thermomechanical loading. Géotechnique, 59, 319–329.CrossRefGoogle Scholar
François, B., Laloui, L. and Laurent, C. (2009) Thermo-hydro-mechanical simulation of ATLAS in situ large scale test in Boom Clay. Computers and Geotechnics, 36, 626–640.CrossRefGoogle Scholar
Gens, A., Valleján, B., Zandarín, M.T and Sánchez, M. (2013) Homogenization in clay barriers and seals: Two case studies. Journal of Rock Mechanics and Geotechnical Engineering, 5, 191–199.CrossRefGoogle Scholar
Harrington, J.F., Volckaert, G. and Noy, D.J. (2014) Long-term impact of temperature on the hydraulic permeability of bentonite. Pp. 589–601 in: Clays in Natural and Engineered Barriers for Radioactive Waste Confinement (S. Norris, J. Bruno, M. Cathelineau, P. Delage, C. Fairhurst, E.C. Gaucher, E.H. Höhn, A. Kalinichev, P. Lalieux and P. Sellin, editors). Special Publications, 400, Geological Society, London.CrossRefGoogle Scholar
Horseman, S., Higgo, J.J.W., Alexander, J. and Harrington, J.F. (1996) Water, Gas and Solute Movement through Argillaceous Media. Report No. CC-96/1 to OECD/NEA Working Group on Measurement and Physical Understanding of Groundwater Flow through Argillaceous Media. Nuclear Energy Agency, OECD, Paris.Google Scholar
Johannesson, L.E., Boergesson, L. and Sanden, T (1995) Compaction of bentonite blocks. Development of technique for industrial production of blocks which are manageable by man, Sweden. Svensk Kärnbränslehantering AB (SKB) Technical Report TR-95-19.Google Scholar
Li, X. (2013) TIMODAZ: A successful international cooperation project to investigate the thermal impact on the EDZ around a radioactive waste disposal in clay host rocks. Journal of Rock Mechanics and Geotechnical Engineering, 5, 231–242.CrossRefGoogle Scholar
Monfared, M., Sulem, J., Delage, P. and Mohajerani, M. (2012) On the THM behaviour of a sheared Boom clay sample: Application to the behaviour and sealing properties of the EDZ. Engineering Geology, 124, 47–58.CrossRefGoogle Scholar
Pusch, R. (2002) The buffer and backfill handbook, Part 1: Definitions, basic relationships, and laboratory methods. Svensk Kärnbränslehantering AB (SKB) Technical Report TR-02-20.Google Scholar
Romero, E., Gens, A. and Lloret, A. (2001) Temperature effects on the hydraulic behaviour of an unsaturated clay. Geotechnical and Geological Engineering, 19, 311–332.CrossRefGoogle Scholar
Romero, E., Lima, A., Gens, A. and Vaunat, J. (2013) Determination of the thermal parameters of a clay from heating cell tests. 18th International Conference on Soil Mechanics and Geotechnical Engineering, Paris, France.Google Scholar
Villar, M. V and Lloret, A. (2004) Influence of temperature on the hydro-mechanical behaviour of a compacted bentonite. Applied Clay Science, 26, 337–350.CrossRefGoogle Scholar
Wersin, P., Johnson, L.H. and McKinley, I.G. (2007) Performance of the bentonite barrier at temperatures beyond 100°C: A critical review. Physics and Chemistry of the Earth, Parts A/B/C, 32, 780–788.CrossRefGoogle Scholar