Abstract
A compacted bentonite buffer is one of the most important components in engineered barrier systems for the disposal of high-level radioactive waste produced by nuclear power generation. The compacted bentonite buffer contributes significantly to the protection of the disposal canister against the external impact and penetration of groundwater. Therefore, it must satisfy thermo–hydraulic–mechanical requirements. Although thermal–hydraulic properties have been investigated extensively, the mechanical properties of compacted bentonite buffers have not been comprehensively evaluated. Therefore, a series of uniaxial compression and point load tests were conducted in this study. The mechanical properties of Korean compacted bentonite specimens with varying water contents and dry densities, such as uniaxial compressive strength, elastic modulus, and point load index, were obtained. As the dry density increased, the uniaxial compressive strength, elastic modulus, and point load strength index increased, whereas Poisson’s ratio decreased slightly. This indicates that the uniaxial compressive strength, elastic modulus, and point load strength index are proportional to the dry density. However, the mechanical properties and water content do not exhibit a significant correlation.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Data availability
The datasets generated and/or analyzed during the current study are available from the corresponding author upon reasonable request.
References
ASTM (2014) Standard test method for compressive strength and elastic moduli of intact rock core specimens under varying states of stress and temperatures. ASTM Int 10:D7012–D7014
Bieniawski Z, Bernede M (1979) Suggested methods for determining the uniaxial compressive strength and deformability of rock materials: part 1. Suggested method for determining deformability of rock materials in uniaxial compression. Int J Rock Mech Min Sci 2:138–140. https://doi.org/10.1016/0148-9062(79)91451-7
Cho WJ (2017) Radioactive waste disposal. Korea Atomic Energy Research Institute. KAERI/GP-495/2017
Dixon D, Gray M, Thomas A (1985) A study of the compaction properties of potential clay–sand buffer mixtures for use in nuclear fuel waste disposal. Eng Geol 21:247–255. https://doi.org/10.1016/0013-7952(85)90015-8
ISRM (1985) Suggested method for determining point load strength. Int J Rock Mech Min Sci Geomech Abstracts 22(2):51–60
JNC (1999) H12 project to establish the scientific and technical basis for HLW disposal in Japan (supporting report 2) Repository design and engineering technology. In: Japan Nuclear Cycle Development Institute, Tokai, Japan
Juvankoski M (2013) Buffer design 2012. POSIVA 2012-14, Posiva Oy, Eurajoki
Kim HJ (2018) Estimation for the uniaxial compressive strength of rocks in Korea using the point load test. Tunn Undergr Space 28:72–96. https://doi.org/10.7474/TUS.2018.28.1.072
Kim J-S, Yoon S, Cho W-J, Choi Y-C, Kim G-Y (2018) A study on the manufacturing characteristics and field applicability of engineering-scale bentonite buffer block in a high-level nuclear waste repository. J Nucl Fuel Cycle Waste Technol 16:123–136. https://doi.org/10.7733/jnfcwt.2018.16.1.123
Kim KI, Lee C, Lee J, Kim JS, Cho DK (2021) Estimation of disposal spacing and rock maass conditions for high-efficiency repository based on temperature limit requirement of bentonite buffer. Korea Atomic Energy Research Institute,
Komine H (2004) Simplified evaluation for swelling characteristics of bentonites. Eng Geol 71:265–279. https://doi.org/10.1016/S0013-7952(03)00140-6
Lee C, Lee JW, Kim GY (2020) Numerical simulations of coupled thermo-hydro-mechanical (THM) behavior of FEBEX bentonite. Korea Atomic Energy Research Institute,
Lee CS (2021) Principal and Practice of Geotechnical Engineering, YEAMOONSA, Paju, Gyeonggi-do, Korea
Lee JO, Cho WJ, Kwon S (2011) Thermal–hydro–mechanical properties of reference bentonite buffer for a Korean HLW repository. Tunn Undergr Space 21:264–273. https://doi.org/10.7474/TUS.2011.21.4.264
Lee JO, Lim JG, Kang IM, Kwon S (2012) Swelling pressures of compacted Ca-bentonite. Eng Geol 129:20–26. https://doi.org/10.1016/j.enggeo.2012.01.005
Lim S, Yu S, Kim Y, Kim M (2020) Poisson’s Ratio prediction of soil using the consolidation undrained triaxial compression test. J Korea Soc Agric Eng 62:45–51. https://doi.org/10.5389/KSAE.2020.62.4.045
Mehrotra PK (2014) Powder processing and green shaping. Comprehensive Hard Materials. Elsevier, Amsterdam, pp 213–235. https://doi.org/10.1016/B978-0-08-096527-7.00007-6
Park TJ, Yoon S, Lee C, Cho DK (2021) Review and strategy for study on korean buffer characteristics under the elevated temperature conditions: mineral transformation and radionuclide retardation perspective. J Nucl Fuel Cycle Waste Technol (JNFCWT) 19(4):459–467
Pusch R (1979) Highly compacted sodium bentonite for isolating rock-deposited radioactive waste products. Nucl technol 45:153–157. https://doi.org/10.13182/NT79-A32305
Ritola J, Pyy E (2012) Isostatic compression of buffer blocks. In: Middle scale. Posiva Oy,
Villar M, Fernández-Soler J, Delgado Huertas A, Reyes E, Linares J, Jiménez de Cisneros C, Huertas F, Caballero E, Leguey S, Cuevas J (2006) The study of Spanish clays for their use as sealing materials in nuclear waste repositories: 20 years of progress. J Iber Geol 32:15–36
Villar MV (2004) Thermo–hydro–mechanical characteristics and processes in the clay barrier of a high level radioactive waste repository. State of the Art Report
Xu Y, Zeng Z, Lv H (2019) Temperature dependence of apparent thermal conductivity of compacted bentonites as buffer material for high-level radioactive waste repository. Appl Clay Sci 174:10–14. https://doi.org/10.1016/j.clay.2019.03.017
Yoo M, Choi HJ, Lee MS, Lee SY (2015) Chemical and mineralogical characterization of domestic bentonite for a buffer of an HLW repository. Korea Atomic Energy Research Institute,
Yoon S, Go G-H, Lee J-O, Kim G-Y (2019) Evaluation of water suction for the compacted bentonite buffer considering temperature variation. J Korean Geotech Soc 35:7–14. https://doi.org/10.7843/kgs.2019.35.11.7
Yoon S, Kim M-J, Park S, Kim G-Y (2021) Thermal conductivity prediction model for compacted bentonites considering temperature variations. Nucl Eng Technol. https://doi.org/10.1016/j.net.2021.05.001
Yoon S, Lee G-J, Go G-H (2022) Linear thermal expansion behavior of compacted bentonite buffer materials. Case Stud Therm Eng 32:101889. https://doi.org/10.1016/j.csite.2022.101889
Zheng L, Rutqvist J, Birkholzer JT, Liu H-H (2015) On the impact of temperatures up to 200 C in clay repositories with bentonite engineer barrier systems: a study with coupled thermal, hydrological, chemical, and mechanical modeling. Eng Geol 197:278–295. https://doi.org/10.1016/j.enggeo.2015.08.026
Acknowledgements
This research was supported by the Nuclear Research and Development Program of the National Research Foundation of Korea (2021M2E3A2041351), and Institute for Korea Spent Nuclear Fuel and National Research Foundation of Korea (2021M2E1A1085193).
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Yoon, S., Jeong, H., Lee, HL. et al. Evaluation of uniaxial compression and point load tests for compacted bentonites. Acta Geotech. 18, 4633–4644 (2023). https://doi.org/10.1007/s11440-023-01844-1
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11440-023-01844-1