Insights into Hydro-mechanical Behavior of Bentonite Based Seals for Deep Geological Repositories

  • Nadia MokniEmail author
  • Agustin Molinero Guerra
Conference paper
Part of the Sustainable Civil Infrastructures book series (SUCI)


Pre-compacted blocks of bentonite sand mixture are candidate materials for sealing plugs of radioactive waste disposal. Choice of this material is especially based on its swelling capacity allowing all technological gaps existing between the bentonite based core and the host rock to be sealed. Under real repository conditions, the sealing plugs will start to take water from the host rock and swell. Thereby, a swelling pressure will develop in the radial direction against the host rock and in the axial direction against the concrete confining structures. One important characteristic of this type of heterogeneous mixture is the multimodal nature of its porous network. This multimodal porosity and the highly heterogeneous fabric of the mixture result in a quite complex behaviour during hydration. The paper describes numerical analysis of small scale tests performed on compacted samples of bentonite and sand mixture (70/30 in dry mass). The A coupled HM formulation that incorporates the relevant processes involved in the problem under consideration has been adopted. Technological gaps and heterogeneous structural distribution of the mixture were demonstrated to have an effect on swelling pressure evolution.


  1. Alonso, E.E., Gens, A., Josa, A.: A constitutive model for partially saturated soils. Géotechnique 40(3), 405–430 (1990)CrossRefGoogle Scholar
  2. Alonso, E.E., Romero, E., Hoffmann, C.: Hydromechanical behavior of compacted granular expansive mixtures: experimental and constitutive study. Géotechnique 61(4), 329–377 (2011)CrossRefGoogle Scholar
  3. Barnichon, J.D., Deleruyelle, F.: Sealing experiments at the Tournemire URL. EUROSAFE (2009)Google Scholar
  4. Chen, Y.G., Cui, Y.J., Tang, A.M., Wang, Q., Ye, W.M.: A preliminary study on hydraulic resistance of bentonite/host-rock seal interface. Geotechnique 64(12), 997–1002 (2014)CrossRefGoogle Scholar
  5. Gens, A., Vallejan, B., Sánchez, M., Imbert, C., Villar, M.V., Van Geet, M.: Hydromechanical behaviour of a heterogeneous compacted soil: experimental observations and modelling. Géotechnique 61(5), 367–386 (2011)CrossRefGoogle Scholar
  6. Gens, A., Alonso, E.E.: A framework for the behaviour of unsaturated expansive clays. Can. Geotech. J. 29, 1013–1032 (1992)CrossRefGoogle Scholar
  7. Imbert, C., Villar, M.V.: Hydro-mechanical response of a bentonite pellets-powder mixture upon infiltration. Appl. Clay Sci. 32(3–4), 197–209 (2006)CrossRefGoogle Scholar
  8. Lloret, A., Villar, M.V., Sanchez, M., Gens, A.: Advances on the knowledge of the thermo-hydro-mechanical behaviour of heavily compacted “FEBEX” bentonite. Phys. Chem. Earth 32, 701–715 (2007)CrossRefGoogle Scholar
  9. Mokni, N., Barnichon, J.D.: Hydro-mechanical analysis of SEALEX in-situ tests- impact of technological gaps on long term performance of repository seals. Eng. Geol. 205, 81–92 (2016)CrossRefGoogle Scholar
  10. Mokni, N., Barnichon, J.D., Dick, P., Nguyen, S.: Effect of technological macro voids on he performance of compacted bentonite/sand seals for deep geological repositories. Int J. Rock Mech. Min. Sci. 88, 87–97 (2016)Google Scholar
  11. Mokni, N.: Analysis if hydro-mechanical behavior of compacted bentonite/sand mixture using double strcuture formulations. Environ. Earth Sci. 75, 1087 (2016). doi: 10.1007/s12665-016-5872-2 CrossRefGoogle Scholar
  12. Olivella, S., Carrera, J., Gens, A., Alonso, E.E.: Non isothermal multiphase flow of brine and gas through saline media. Transp. Porous Media 15, 271–293 (1994)CrossRefGoogle Scholar
  13. Pusch, R.: Highly compacted sodium bentonite for isolating rock-deposited radio-active waste products. Nucl. Technol. 45(2), 153–157 (1979). United StatesGoogle Scholar
  14. Saba, S.: Hydro-mechanical behaviour of bentonite-sand mixture used as sealing material in radioactive waste disposal galleries. Ph.D. thesis, Paris-Est University, France (2013)Google Scholar
  15. Saba, S., Delage, P., Lenoir, N., Cui, Y.J., Tang, A.M., Barnichon, J.D.: Further insight into the microstructure of compacted bentonite/sand mixture. Eng. Geol. 168, 141–148 (2014a)CrossRefGoogle Scholar
  16. Saba, S., Barnichon, J.D., Cui, Y.J., Tang, A.M., Delage, P.: Microstructure and anisotropic swelling behaviour of compacted bentonite/sand mixture. J. Rock Mech. Geotech. Eng. 6, 126–132 (2014b)CrossRefGoogle Scholar
  17. Saba, S., Cui, Y.J., Tang, A.M., Barnichon, J.D.: Investigation of the swelling behaviour of compacted bentonite-sand mixture by mock-up tests. Can. Geotech. J. 51(12), 1399–1412 (2014c)CrossRefGoogle Scholar
  18. Sanchez, M., Gens, A., Guimaraes, L., Olivella, S.: A double structure generalized plasticity model for expansive materials. Int. J. Numer. Analyt. Methods Geomech. 29(8), 751–787 (2005)CrossRefGoogle Scholar
  19. Villar, M.V., Gómez-Espina, R., Campos, R., Barrios, I., Gutiérrez-Nebot, L.: Porosity changes due to hydration of compacted bentonite. In: Manusco, C., Jommi, C., Donza, F. (eds.) Unsaturated Soils: Research and Applications, vol. 1, pp. 137–144. Springer, Berlin (2012)CrossRefGoogle Scholar
  20. Wang, Q.: Hydro-mechanical behaviour of bentonite-based materials used for high-level radioactive waste disposal. Ph.D. thesis, Paris-Est University, France (2012)Google Scholar
  21. Wang, Q., Tang, A.M., Cui, Y.J., Delage, P., Gatmiri, B.: Experimental study on the swelling behaviour of bentonite/claystone mixture. Eng. Geol. 124, 59–66 (2012). doi: 10.1016/j.engeo.2011.10.003 CrossRefGoogle Scholar
  22. Wang, Q., Tang, A.M., Cui, Y.J., Barnichon, J.D., Ye, W.M.: A comparative study on the hydro-mechanical behaviour of compacted bentonite/sand plug based on laboratory and field infiltration tests. Eng. Geol. 162, 79–87 (2013a)CrossRefGoogle Scholar
  23. Wang, Q., Cui, Y.J., Tang, A.M., Barnichon, J.D., Saba, S., Ye, W.M.: Hydraulic conductivity and microstructure changes of compacted bentonite/sand mixture during hydration. Eng. Geol. (2013b). doi: 10.1016/j.enggeo.2013.06.013 Google Scholar
  24. Wang, Q., Tang, A.M., Cui, Y.J., Delage, P., Barnichon, J.D., Ye, W.M.: The effects of technological voids on the hydro-mechanical behaviour of compacted bentonite-sand mixture. Soils Found. 53(2), 232–245 (2013c)CrossRefGoogle Scholar
  25. Wang, Q., Tang, A.M., Cui, Y.J., Barnichon, J.D., Ye, W.M.: Investigation of the hydro-mechanical behaviour of compacted bentonite/sand mixture based on the BExM model. Comput. Geotech. 5, 46–52 (2013d)CrossRefGoogle Scholar
  26. Yong, R.N., Boonsinsuk, P., Wong, G.: Formulation of backfill material for a nuclear fuel waste disposal vault. Can. Geotech. J. 23(2), 216–228 (1986)CrossRefGoogle Scholar

Copyright information

© Springer International Publishing AG 2018

Authors and Affiliations

  1. 1.Institute for Radiation Protection and Nuclear Safety (IRSN)Fontenay-aux-RosesFrance
  2. 2.Ecole des Ponts Paris Tech, Laboratoire NavierMarne la ValléeFrance

Personalised recommendations