Abstract
The excavation damaged zone (EDZ) around the backfilled underground structures of a geological repository represents a release path for radionuclides, which needs to be addressed in the assessment of long-term safety. Additionally, the EDZ may form a highly efficient escape route for corrosion and degradation gases, thus limiting the gas overpressures in the backfilled repository structures. The efficiency of this release path depends not only on the shape and extent of the EDZ, but also on the self-sealing capacity of the host rock formation and the prevailing state conditions, such as in situ stresses and pore pressure. The hydro-mechanical and chemico-osmotic phenomena associated with the formation and temporal evolution of the EDZ are complex, thus precluding a detailed representation of the EDZ in conventional modelling tools for safety assessment. Therefore, simplified EDZ models, able to mimic the safety-relevant functional features of the EDZ in a traceable manner are required. In the framework of the Mont Terri Project, a versatile modelling approach has been developed for the simulation of flow and transport processes along the EDZ with the goal of capturing the evolution of hydraulic significance of the EDZ after closure of the backfilled underground structures. The approach draws on both empirical evidence and experimental data, collected in the niches and tunnels of the Mont Terri rock laboratory. The model was benchmarked with a data set from an in situ self-sealing experiment at the Mont Terri rock laboratory. This paper summarises the outcomes of the benchmark exercise that comprises relevant empirical evidence, experimental data bases and the conceptual framework for modelling the evolution of the hydraulic significance of the EDZ around a backfilled tunnel section during the entire resaturation phase.
Editorial handling: P. Bossart and A. G. Milnes.
The abbreviations EDB, EZ-A, EZ-B, FE, GP, GP-A, GS, HG-A, SEH denote in situ experiments at the Mont Terri rock laboratory.
This is paper #8 of the Mont Terri Special Issue of the Swiss Journal of Geosciences (see Bossart et al. 2017, Table 3 and Fig. 7).
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Alcolea, A., Kuhlmann, U. (2017). Mont Terri HG-A experiment (phase 21). Inverse fow modelling of the hydraulic properties of the EDZ. Mont Terri Technical Note 2016-76 (in prep.).
Alcolea, A., Kuhlmann, U., Marschall, P., Lisjak, A., Grasselli, G., Mahabadi, O., de La Vaissie`re, R., Leung, H., & Shao, H. (2016). A pragmatic approach to abstract the EDZ around tunnels of a geological radioactive waste repository—Application to the HG-A experiment in Mont Terri. Geological Society, London, Special Publications, 443, SP443–8.
Alcoverro, J., Olivella, S., & Alonso, E. E. (2014). Modelling fluid flow in Opalinus Clay excavation damage zone. A semianalytical approach. Geological Society, London, Special Publications, 415(1), 143–166.
Alheid, H. J., Aranyossy J. F., Blümling P., Hoteit N., & Van Geet M. (2007). EDZ Development and Evolution (RTDC 4). EDZ development and evolution. State of the art. NF-PRO. Contract Number F16W-CT-2003-02389. European Commission, Luxembourg.
Aranyossy, J. F., Mayor, J. C., Marschall, P., Plas, F., Blumling, P., Van Geet, M., Armand, G., Techer, I., Alheid, A. J., Rejeb, A., Pinettes, P., Balland, C., Popp, T., Rothfuchs, T., Matray, J. M., De Craen, M., Wieczorek, K., Pudewills, A., Czaikowski, O., Hou, Z., & Fröhlich, H. (2008). EDZ Development and Evolution (RTDC 4). In nuclear science and technology. Understanding and Physical and Numerical Modelling of the Key Processes in the Near Field and their Coupling for Different Host Rocks and Repository Strategies NF-PRO) Final Synthesis Report (D. 4.5.3). FP6-EURATOM/NF-PRO, F16W-CT-2003-02389 (pp. 150–197). European Commission, Luxembourg.
Armand, G., Leveau, F., Nussbaum, C., De La Vaissiere, R., Noiret, A., Jaeggi, D., et al. (2013a). Geometry and properties of the excavation-induced fractures at the Meuse/Haute-Marne URL drifts. Rock Mechanics and Rock Engineering, 47(1), 21–41.
Armand, G., Noiret, A., Zghondi, J., & Seyedi, D. M. (2013b). Shortand long-term behaviors of drifts in the Callovo-Oxfordian claystone at the Meuse/Haute-Marne underground research laboratory. Journal of Rock Mechanics and Geotechnical Engineering, 5(3), 221–230.
Blümling, P., Bernier, F., Lebon, P., & Martin, C. D. (2007). The excavation damaged zone in clay formations time-dependent behaviour and influence on performance assessment. Physics and Chemistry of the Earth, Parts A/B/C, 32(8), 588–599.
Bossart, P., Bernier, F., Birkholzer, J., Bruggeman, C., Connolly, P., Dewonck, S., Fukaya, M., Herfort, M., Jensen, M., Matray, J-M., Mayor, J. C., Moeri, A., Oyama, T., Schuster, K., Shigeta, N., Vietor, T., & Wieczorek, K. (2017). Mont Terri rock laboratory, 20 years of research: introduction, site characteristics and overview of experiments. Swiss Journal of Geosciences, 110. https://doi.org/10.1007/s00015-016-0236-1 (this issue).
Bossart, P., Meier, P. M., Moeri, A., Trick, T., & Mayor, J. C. (2002). Geological and hydraulic Characterization of the excavation disturbed zone in the Opalinus Clay of the Mont Terri Rock Laboratory. Engineering Geology, 66, 19–38.
Bossart, P., Trick, T., Meierand, P. M., & Mayor, J. C. (2004). Structural and hydrogeological Characterization of the excavation-disturbed zone in the Opalinus Clay (Mont Terri Project, Switzerland). Applied Clay Science, 26, 429–448.
Diederichs, M. S., & Kaiser, P. K. (1999). Stability of large excavations in laminated hard rock masses: the Voussoir analogue revisited. International Journal of Rock Mechanics and Mining Sciences, 36(1), 97–118.
DIT-UPC. (2000). CODE_BRIGHT, A 3-D program for thermohydro-mechanical analysis in geological media. User’s guide. Barcelona: CIMNE.
Einstein, H. H. (2002). Tunnels in Opalinus Clayshale. A review of case histories and new developments. Tunnelling and Underground Space Technology, 15(1), 13–29.
Ferrari, A., Favero, V., Marschall, P., & Laloui, L. (2014). Experimental analysis of the water retention behaviour of shales. International Journal of Rock Mechanics and Mining Sciences, 72, 61–70.
Harrington, J., Volckaert, G., Jacobs, E., Maes, N., Areias, L., Charlier, R., & Granet, S. (2013). Summary report: experiments and modelling of excavation damage zone (EDZ) behaviour in argillaceous and crystalline rocks (Work Package 4). EC FORGE Project Report D, 4.
Itasca. (2012). FLAC3D (Fast Lagrangian Analysis of Continua). Version 5.01. Itasca Consulting Group Inc., Minnesota, USA.
Labiouse, V., & Vietor, T. (2014). Laboratory and in situ simulation tests of the excavation damaged zone around galleries in Opalinus Clay. Rock Mechanics and Rock Engineering, 47(1), 57–70.
Lanyon, G. W. (2011). Excavation damaged zones assessment. Report NWMO DGR-TR-25 2011-21. (p. 111).
Lanyon, G. W., Marschall, P., Trick, T., De La Vaissiere, R., Shao, H., & Leung, H. (2009). Hydromechanical Evolution and Self-Sealing of Damage Zones around a Microtunnel in a Claystone Formation of the Swiss Jura Mountains. In 43rd U.S. Rock Mechanics Symposium & 4th U.S.—Canada Rock Mechanics Symposium (pp. 652–663). American Rock Mechanics Association.
Lanyon, G. W., Marschall, P., Trick, T., De La Vaissiere, R., Shao, H., & Leung, H. (2014). Self-sealing experiments and gas injection tests in a backfilled microtunnel of the Mont Terri URL. Geological Society, London, Special Publications, 400(1), 93–106.
Lanyon, G. W., & Senger, R. (2011). A Structured approach to the derivation of effective properties for combined water and gas flow in the EDZ. Transport in Porous Media, 90(1), 95–112.
Lisjak, A., Garitte, B., Grasselli, G., Müller, H., & Vietor, T. (2015). The excavation of a circular tunnel in a bedded argillaceous rock (Opalinus Clay): short-term rock mass response and FDEM numerical analysis. Tunnelling and Underground Space Technology, 45, 227–248.
Lisjak, A., Tatone, B. S. A., Mahabadi, O. K., Grasselli, G., Marschall, P., Lanyon, G. W., et al. (2016). Hybrid finitediscrete element simulation of the EDZ formation and mechanical sealing process around a microtunnel in Opalinus Clay. Rock Mechanics and Rock Engineering, 49(5), 1849–1873.
Marschall, P., Distinguin, M., Shao, H., Bossart, P., Enachescu, C., & Trick, T. (2006). Creation and evolution of damage zones around a microtunnel in a claystone formation of the Swiss Jura Mountains. In International Symposium and Exhibition on Formation Damage Control, Society of Petroleum Engineers.
Marschall, P., Horseman, S., & Gimmi, T. (2005). Characterisation of gas transport properties of the Opalinus Clay, a potential host rock formation for radioactive waste disposal. Oil & Gas Science and Technology, 60(1), 121–139.
Marschall, P., Trick, T., Lanyon, G. W., Delay, J., & Shao, H. (2008). Hydro-Mechanical Evolution of Damaged Zones around a Microtunnel in a Claystone Formation of the Swiss Jura Mountains. In The 42nd US Rock Mechanics Symposium (USRMS), American Rock Mechanics Association.
Martin, C. D., Christiansson, R., & Söderhäll, J. (2001). Rock stability considerations for siting and constructing a KBS-3 repository. SKB Technical Report, TR-01-38 (p. 94). Swedish Nuclear Fuel and Waste Management Co, Stockholm, Sweden. http://www.skb.se.
Martin, C. D., & Lanyon, G. W. (2003). EDZ in clay shale: Mont Terri. Mont Terri Technical Report, TR 01-01 (p. 207). Federal Office of Topography (swisstopo), Wabern, Switzerland. http://www.mont-terri.ch.
Nagra. (1997). Geosynthese Wellenberg 1996-Ergebnisse der Untersuchungsphasen I und II. Nagra Technical Report, NTB 96-01 (p. 511). Nagra, Wettingen, Switzerland. http://www.nagra.ch.
Nagra. (2002). Projekt Opalinuston. Synthese der geowissenschaftlichen Untersuchungs ergebnisse. Entsorgungsnachweis für abgebrannte Brennelemente, verglaste hochaktive sowie langlebige mittelaktive Abfälle. Nagra Technical Report, NTB 02-03 (p. 659). Nagra, Wettingen, Switzerland. http://www.nagra.ch.
Nagra. (2008). Effects of post-disposal gas generation in a repository for low- and intermediate-level waste sited in the Opalinus Clay of Northern Switzerland. Nagra Technical Report, NTB 08-07 (p. 175). Nagra, Wettingen, Switzerland. http://www.nagra.ch.
Nagra. (2016). Production, consumption and transport of gases in deep geological repositories according to the Swiss disposal concept. Nagra Technical Report, NTB 16-03, Nagra, Wettingen, Switzerland. http://www.nagra.ch.
Nguyen, T. S., & Le, A. D. (2015). Simultaneous gas and water flow in a damage-susceptible bedded argillaceous rock. Canadian Geotechnical Journal, 52(1), 18–32.
Nussbaum, C., Kloppenburg, A., Caër, T., & Bossart, P. (2017). Tectonic evolution around the Mont Terri rock laboratory, northwestern Swiss Jura: constraints from kinematic forward modelling. Swiss Journal of Geosciences, 110. https://doi.org/10.1007/s00015-016-0248-x (this issue).
Poller, A., Smith, P., Mayer, G., & Hayek, M. (2014). Modelling of Radionuclide Transport along the Underground Access Structures of Deep Geological Repositories. Nagra Technical Report, NTB 14-10 (p. 166). Nagra, Wettingen, Switzerland. http://www.nagra.ch.
Pruess, K., Oldenburg, C., & Moridis, G. (2012). TOUGH2 user’s guide, Version 2.1 Lawrence Berkeley Laboratories, Report LBL-43134, Berkeley, CA, USA.
Rejeb, A., Slimane, K. B., Cabrera, J., Matray, J. M., & Savoye, S. (2008). Hydro-mechanical response of the Tournemire argillite to the excavation of underground openings: Unsaturated zones and mine-by-test experiment. In Thermo-hydromechanical and chemical coupling in geomaterials and applications: proceedings of the 3 international symposium GeoProc’2008 (pp. 649–656). Wiley.
Senger, R. K., Lanyon, G. W., & Marschall, P. (2013). Modeling the Hydraulic and Two-phase Flow Behaviour of the Heterogeneous, Fractured EDZ in the Opalinus Clay during the HG-A Experiment at the Mont Terri URL. In Proceedings of the Fourth European Association of Geoscientists & Engineers (EAGE) Shale workshop. Shales: what do they have in common? (pp 148–152). European Association of Geoscientists & Engineers.
Shao, H., Xu, W., Marschall, P., Kolditz, O., & Hesser, J. (2015). Numerical interpretation of gas-injection tests at different scales. Geological Society, London, Special Publications, 415(1), 203–212.
Steiner, W. (1996). Tunnelling in squeezing rocks: case histories. Rock Mechanics and Rock Engineering, 29(4), 211–246.
Suckling, P., Avis, J., Calder, N., Humphreys, P., King, F., & Walsh, R. (2012). T2GGM Version 3.1: gas generation and transport code. Nuclear Waste Management Organization Report NWMO TR-2012-23. Toronto, Canada.
Tsang, C. F., Bernier, F., & Davies, C. (2005). Geohydromechanical processes in the Excavation Damaged Zone in crystalline rock, rock salt, and indurated and plastic clays in the context of radioactive waste disposal. International Journal of Rock Mechanics and Mining Sciences, 42(1), 109–125.
Walsh, R., Nasir, O., Leung, H., & Avis, J. (2015). Numerical Characterization of the Excavation Damaged Zone in the HG-A Experiment. In Proceedings: International High-Level Radioactive Waste Management, Charleston, SC.
Wilson, C. R., Witherspoon, P. A., Long, J. C. S., Galbraith, R. M., DuBois, A. O., & McPherson, M. J. (1983). Large-scale hydraulic conductivity measurements in fractured granite. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 20(6), 269–276.
Xu, W., Shao, H., Marschall, P., Hesser, J., & Kolditz, O. (2013). Analysis of flow path around the sealing section HG-A experiment in the Mont Terri Rock Laboratory. Environmental Earth Sciences, 70(7), 3363–3380.
Yong, S. (2007). A three-dimensional analysis of excavation-induced perturbations in the Opalinus Clay at the Mont Terri Rock Laboratory. Ph.D dissertation, Swiss Federal Institute of Technology in Zürich, Zürich, Switzerland, p. 167.
Acknowledgements
This work was supported by ANDRA, BGR, Nagra and NWMO via the Mont Terri Consortium. The authors would like to thank Dr. Paul Bossart, Mr. T. Theurillat, Dr. D. Jäggi of the Mont Terri consortium together with the many contractors who have supported the experiments for their invaluable assistance in the technical planning and performance of the experiment. The valuable review comments and suggestions by Prof. D. Martin (University of Edmonton, Canada) and Prof. T.S. Nguyen (Canadian Nuclear Safety Commission, Ottawa) for improving the technical quality of this paper are highly appreciated.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2018 Springer International Publishing AG
About this chapter
Cite this chapter
Marschall, P. et al. (2018). Hydro-mechanical evolution of the EDZ as transport path for radionuclides and gas: insights from the Mont Terri rock laboratory (Switzerland). In: Bossart, P., Milnes, A. (eds) Mont Terri Rock Laboratory, 20 Years. Swiss Journal of Geosciences Supplement, vol 5. Birkhäuser, Cham. https://doi.org/10.1007/978-3-319-70458-6_9
Download citation
DOI: https://doi.org/10.1007/978-3-319-70458-6_9
Published:
Publisher Name: Birkhäuser, Cham
Print ISBN: 978-3-319-70457-9
Online ISBN: 978-3-319-70458-6
eBook Packages: Earth and Environmental ScienceEarth and Environmental Science (R0)