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Excavation Disturbed Zone: Assessment of Its Hydraulic Properties Based on Surface Investigations

Published online by Cambridge University Press:  10 February 2011

S. Vomvoris ,
P. Blomling ,
G. W. Lanyon  and
C. R. Watson
S. Vomvoris
Affiliation:
Nagra, Swiss National Cooperative for the Disposal of Radioactive Waste, Hardstrasse 73, CH-5430 Wettingen, Switzerland, [email protected]
P. Blomling
Affiliation:
Nagra, Swiss National Cooperative for the Disposal of Radioactive Waste, Hardstrasse 73, CH-5430 Wettingen, Switzerland
G. W. Lanyon
Affiliation:
GeoScience Ltd, The Falmouth Business Park, Bickland Water Road, FALMOUTH Cornwall TR11 4SZ, United Kingdom
C. R. Watson
Affiliation:
GeoScience Ltd, The Falmouth Business Park, Bickland Water Road, FALMOUTH Cornwall TR11 4SZ, United Kingdom
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Abstract

The approach followed by Nagra for the assessment of the hydraulic properties of the excavation disturbed zone (EDZ) around a potential future underground repository site for low-level and medium-level short-lived radioactive wastes is presented. In the approach particular emphasis was placed on assessing, under realistic-conservative assumptions1, an appropriate way to represent the EDZ within the context of performance assessment (PA). Calculated stress changes due to the openings were mapped onto changes of the mechanical aperture of the rock fractures. The resulting changes of hydraulic properties of the EDZ were then computed, with analytical (simple, continuum-type approximation) and numerical (fracture network representation) methods. The results of both computations were used as the basis to: i) provide hydraulic properties for the EDZ used in PA models; ii) assess whether these properties are conservative, i.e., higher values than expected, or not.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 506: Symposium – Scientific Basis for Nuclear Waste Management XXI , 1997 , 873
Copyright
Copyright © Materials Research Society 1998

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References

REFERENCES

1 SKB 91 - Final Disposal of Spent Nuclear Fuel. Importance of Bedrock for Safety, SKB Stockholm (1992).Google Scholar
2 Damjanac, B., A three-dimensional Numerical Model of Water Flow in a Fractured Rock Mass, PhD Thesis University of Minnesota (1996).Google Scholar
3 Tsang, C.-F., Coupled processes associated with nuclear waste repositories, Academic Press, USA (1987).Google Scholar
4 Kelsall, P. C., Case, J. B., Chabannes, C. R., Evaluation of excavation-induced changes in rock permeability, Int. Journal of Rock Mechanics and Mining Sciences and Geomechanical Abstracts, Vol 21 No. 3 pp 123–135 Pergamon Press (1987).Google Scholar
5 Nagra, Geosynthese Wellenberg 1996: Ergebnisse der Untersuchungsphases I und II, Nagra Technical Report, NTB 96-01, in press (1997).Google Scholar
6 Snow, D. T., Rock fracture spacings, openings and porosities. Journal of Soil Mechanics and Foundations, Division of American Society of Civil Engineers, 94, SM1, 73–91 (1968).Google Scholar
7 Barton, N. and Bakhtar, K., Description and modelling of rock joints for the hydro-thermal-mechanical design of Nuclear Waste Vaults, AECL report TR-418, AECL, Whiteshell Nuclear Research Establishment, Canada (1987).Google Scholar
8 Itasca Consulting Group Inc., FLAC3D - Fast Langrangian Analysis of Continua in 3-Dimensions, Version 1.1, Minneapolis, USA (1995).Google Scholar
9 Glawe, U. and Blumling, P., Felsmechanik-Datensatz: in situ Spannungen und erste Resultate felsmechanischer Berechnungen fLr den Standort Wellenberg CH, submitted to Felsbau (1997).Google Scholar
10 Lanyon, G. W. and Watson, C. R., Calculation of effective hydraulic conductivity in the EDZ around seal zones, Nagra Internal Report (1997).Google Scholar
11 Olsson, O. and Winberg, A., Current Understanding of extent and properties of the excavation disturbed zone and its dependence on excavation method. In proceedings of EDZ Workshop, Winnipeg, Canadian Nuclear Society (1996).Google Scholar
12 NAGRA NTB 93-22, , Kristallin-I: Safety Assessment Report, Nagra Technical Report 93-22, Nagra, Wettingen, Switzerland (1994).Google Scholar