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Geomechanics and Engineering Volume 41, Number 2, April25 2025 (Special Issue) pages 165-175 DOI: https://doi.org/10.12989/gae.2025.41.2.165 |
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 open accessWater infiltration dynamics in bentonite-based engineered barrier systems investigated by time-lapse photography |
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Jinwoo Kim, Hwan-Hui Lim, Jin-Seop Kim and Tae-Hyuk Kwon
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| Abstract | ||
| The long-term disposal of high-level radioactive waste (HLW) in deep geological repositories requires the reliable performance of engineered barrier systems (EBS). Compacted bentonite, widely used for its high swelling capacity, low permeability, and self-sealing properties, plays a critical role in these barriers. However, understanding the complex coupled thermo-hydro-mechanical (THM) behavior governing water infiltration dynamics remains a significant challenge, especially when gap spaces (or technological voids) are present. This study investigates water infiltration dynamics in bentonite-based EBS using a novel laboratory-scale experimental setup. Time-lapse photography was employed to monitor the evolution of hydration and swelling under thermal gradients and varying gap sizes, simulating repository conditions. The experimental program was designed to compare the effects of two gap sizes on infiltration rates, swelling behavior, and desiccation cracking. Results demonstrated that larger void spaces accommodated greater swelling, leading to lower dry density and higher permeability, while smaller gaps restricted desiccation cracking due to mechanical constraints. The correlation between pixel intensity and water content allowed the derivation of a linear calibration model, enabling real-time, non-destructive estimation of moisture distribution in bentonite. Findings in this study highlight the interplay between gap size, water infiltration, and thermal effects, emphasizing the need for optimized EBS designs to balance mechanical integrity and hydraulic performance. It is anticipated that the insights provided by this study contribute to the refinement of predictive models and advancing the safe and effective containment of HLW over geological timescales. | ||
| Key Words | ||
| bentonite; engineered barrier systems; gap space; high-level radioactive waste disposal; THM behavior; water infiltration | ||
| Address | ||
| Jinwoo Kim: Disposal Performance Demonstration Research Division, Korea Atomic Energy Research Institute (KAERI), Daejeon 34057, Republic of Korea; Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea Hwan-Hui Lim: Department of Structural Systems & Site Safety Evaluation, Korea Institute of Nuclear Safety(KINS), Daejeon 34045, Republic of Korea Jin-Seop Kim: Disposal Performance Demonstration Research Division, Korea Atomic Energy Research Institute (KAERI), Daejeon 34057, Republic of Korea Tae-Hyuk Kwon: Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea | ||