Analysis of hydro-mechanical behaviour of compacted bentonite/sand mixture using a double structure formulation

  • Nadia Mokni
Thematic Issue
Part of the following topical collections:
  1. DECOVALEX 2015


In this paper, a double structure formulation is used to describe the behaviour of compacted bentonite/sand mixtures intended as sealing material in underground repositories for nuclear waste. The formulation accounts for the presence of two distinct porosity levels in the material as revealed in the pore size distributions determined by mercury intrusion porosimetry technique. Non-equilibrium hydraulic conditions are assumed between micro and macroporosities. A water exchange term between the two porosities is determined. Experimental data obtained in the laboratory were analysed allowing determination of the hydro-mechanical (HM) parameters used in the modelling. These parameters were then used in modelling a 1:10 scale mock-up representative of the large-scale SEALEX performance experiments. It was observed that the model reproduced well the main features related to the swelling pressure development during hydration under confined conditions. Moreover, it allowed analysing interesting information not available from direct laboratory measurements (micro and macroporosities and suctions). The analysis is then up-scaled to the description of large-scale SEAling EXperiment (SEALEX). A challenging task consisted in predictions of field observations using the same hydraulic and mechanical parameters employed in the modelling of the small-scale laboratory tests. The model was able to predict correctly the global HM behaviour of the bentonite-based seal considering the uncertainties and heterogeneities associated with the fabrication and installation processes of the bentonite-based blocks.


Swelling pressure MX80 bentonite/sand mixture In situ tests Microstructure Double structure Technological gap 



The author would like to thank AITEMIN (SPAIN) and ENPC-CERMES (France) our partners in this project.


  1. Alonso EE (1998) Modelling expansive soil behaviour. In: Proceedings of the second international conference on unsaturated soil, Beijing, China, 27–30 August 1998Google Scholar
  2. Alonso EE, Gens A, Josa A (1990) A constitutive model for partially saturated soils. Géotechnique 40(3):405–430CrossRefGoogle Scholar
  3. Alonso EE, Vaunat J, Gens A (1999) Modelling the mechanical behavior of expansive clays. Eng Geol 54:173–183CrossRefGoogle Scholar
  4. Alonso EE, Romero E, Hoffmann C (2011) Hydromechanical behavior of compacted granular expansive mixtures: experimental and constitutive study. Géotechnique 61(4):329–377CrossRefGoogle Scholar
  5. Barnichon JD, Deleruyelle F (2009) Sealing experiments at the Tournemire URL. EUROSAFEGoogle Scholar
  6. Bear J, Bachmat Y (1990) Introduction to modeling of transport phenomena in porous media. Kluwer Acad., New YorkCrossRefGoogle Scholar
  7. Chen YG, Cui YJ, Tang AM, Wang Q, Ye WM (2014) A preliminary study on hydraulic resistance of bentonite/host-rock seal interface. Geotechnique 64(12):997–1002CrossRefGoogle Scholar
  8. Gatabin C, Touze G, Imbert C, Guillot W, Billaud P (2008) ESDRED Project, Module 1-Selection and THM characterisation of the buffer material. In: International conference underground disposal unit design and emplacement processes for deep geological repository, Prague, 16–18 June 2008Google Scholar
  9. Gens A, Alonso EE (1992) A framework for the behaviour of unsaturated expansive clays. Can Geotech J 29:1013–1032CrossRefGoogle Scholar
  10. Gens A, Vallejan B, Sánchez M, Imbert C, Villar MV, Van Geet M (2011) Hydromechanical behaviour of a heterogeneous compacted soil: experimental observations and modelling. Géotechnique 61(5):367–386CrossRefGoogle Scholar
  11. Hassanizadeh SM (1986) Derivation of basic equations of mass transport in porous media, part 2. Macroscopic balance laws. Transp Porous Media 9:196–206Google Scholar
  12. Hassanizadeh SM (1988) Modelling species transport by concentrated brine in aggregated porous media. Transp Porous Media 3:299–318Google Scholar
  13. Imbert C, Villar MV (2006) Hydro-mechanical response of a bentonite pellets-powder mixture upon infiltration. Appl Clay Sci 32(3–4):197–209CrossRefGoogle Scholar
  14. Kozeny J (1927) Ueber kapillare leitung des wassers im boden. Sitzungsber Akad. Wiss. Wien 136(2a):271–306Google Scholar
  15. Lloret A, Villar MV, Sanchez M, Gens A (2007) Advances on the knowledge of the thermo-hydro-mechanical behaviour of heavily compacted “FEBEX” bentonite. Phys Chem Earth 32:701–715CrossRefGoogle Scholar
  16. Mokni N, Barnichon JD (2016) Hydro-mechanical analysis of SEALEX in situ tests- Impact of technological gaps on long term performance of repository seals. Eng Geol 205:81–92CrossRefGoogle Scholar
  17. Montes-Hernandez G, Duplay J, Martinez L, Mendoza C (2003) Swelling-shrinkage kinetics of MX80 bentonite. Appl Clay Sci 22(6):279–293CrossRefGoogle Scholar
  18. Olivella S, Carrera J, Gens A, Alonso EE (1994) Non isothermal multiphase flow of brine and gas through saline media. Transp Porous Media 15:271–293CrossRefGoogle Scholar
  19. Pusch R (1979) Highly compacted sodium bentonite for isolating rock-deposited radio-active waste products. Nucl Technol 45(2):153–157Google Scholar
  20. Saba S (2013) Hydro-mechanical behaviour of bentonite-sand mixture used as sealing material in radioactive waste disposal galleries. Ph.D. Thesis, Paris-Est University, FranceGoogle Scholar
  21. Saba S, Delage P, Lenoir N, Cui YJ, Tang AM, Barnichon JD (2014a) Further insight into the microstructure of compacted bentonite/sand mixture. Eng Geol 168:141–148CrossRefGoogle Scholar
  22. Saba S, Barnichon JD, Cui YJ, Tang AM, Delage P (2014b) Microstructure and anisotropic swelling behaviour of compacted bentonite/sand mixture. J Rock Mech Geotech Eng 6:126–132CrossRefGoogle Scholar
  23. Saba S, Cui YJ, Tang AM, Barnichon JD (2014c) Investigation of the swelling behaviour of compacted bentonite-sand mixture by mock-up tests. Can Geotech J 51(12):1399–1412CrossRefGoogle Scholar
  24. Sanchez M, Gens A, Guimaraes L, Olivella S (2005) A double structure generalized plasticity model for expansive materials. Int J Numer Anal Methods Geomech 29(8):751–787CrossRefGoogle Scholar
  25. Sanchez M, Gens A, Olivella S (2011) THM analysis of a large-scale heating test incorporation material fabric changes. Int J Numer Anal Methods Geomech 36(4):391–421CrossRefGoogle Scholar
  26. Van Genuchten R (1978) Calculating the unsaturated hydraulic conductivity with a new, closed-form analytical model. Research Report 78-WR-08, Water Resources Program, Department of Civil Engineering, Princeton Univ., Princeton, NJGoogle Scholar
  27. Villar MV, Gómez-Espina R, Campos R, Barrios I, Gutiérrez-Nebot L (2012) Porosity changes due to hydration of compacted bentonite. In: Manusco C, Jommi C, Donza F (eds) Unsaturated soils: research and applications, vol 1. Springer, Berlin, pp 137–144CrossRefGoogle Scholar
  28. Wang Q (2012) Hydro-mechanical behaviour of bentonite-based materials used for high-level radioactive waste disposal. Ph.D. Thesis, Paris-Est University, FranceGoogle Scholar
  29. Wang Q, Tang AM, Cui YJ, Delage P, Gatmiri B (2012) Experimental study on the swelling behaviour of bentonite/claystone mixture. Eng Geol 124:59–66. doi: 10.1016/j.engeo.2011.10.003 CrossRefGoogle Scholar
  30. Wang Q, Tang AM, Cui YJ, Barnichon JD, Ye WM (2013a) A comparative study on the hydro-mechanical behaviour of compacted bentonite/sand plug based on laboratory and field infiltration tests. Eng Geol 162:79–87CrossRefGoogle Scholar
  31. Wang Q, Cui YJ, Tang AM, Barnichon JD, Saba S, Ye WM (2013b) Hydraulic conductivity and microstructure changes of compacted bentonite/sand mixture during hydration. Eng Geol. doi: 10.1016/j.enggeo.2013.06.013 Google Scholar
  32. Wang Q, Tang AM, Cui YJ, Delage P, Barnichon JD, Ye WM (2013c) The effects of technological voids on the hydro-mechanical behaviour of compacted bentonite-sand mixture. Soils Found 53(2):232–245CrossRefGoogle Scholar
  33. Wang Q, Tang AM, Cui YJ, Barnichon JD, Ye WM (2013d) Investigation of the hydro-mechanical behaviour of compacted bentonite/sand mixture based on the BExM model. Comput Geotech 5:46–52CrossRefGoogle Scholar
  34. Wang LL, Bornert M, Chanchole S, Héripré E, Yang DS, Halphen B, Pouya A, Tanguy A, Caldemaison D (2013e) Micro-scale experimental investigation of the swelling anisotropy of the Callovo-Oxfordian argillaceous rock. Clay Miner 48:391–402CrossRefGoogle Scholar
  35. Wang LL, Bornert M, Héripré E, Chanchole S, Pouya A, Halphen B (2015) Microscale insight into the influence of humidity on the mechanical behavior of mudstones. J Geophys Res Solid Earth 120:3173–3186CrossRefGoogle Scholar
  36. Yang DQ, Alonso EE, Rahardjo H (1998) Modelling volumetric behavior of an unsaturated expansive soil. In: 2nd international conference on unsaturated soils, Beijing, China, vol 2, pp 249–254Google Scholar
  37. Yong RN, Boonsinsuk P, Wong G (1986) Formulation of backfill material for a nuclear fuel waste disposal vault. Can Geotech J 23(2):216–228CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  1. 1.Institute for Radiation Protection and Nuclear Safety (IRSN)Fontenay-aux-RosesFrance

Personalised recommendations