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2025 Vol.35, Issue 2 Preview Page

Technical Note

Implementation of Barcelona Basic Model Module into OGS-FLAC3D for Simulating Elasto-Plastic Behavior of Unsaturated Soils

불포화토 탄소성 거동 모사를 위한 OGS-FLAC3D 해석 시뮬레이터 내 Barcelona Basic Model 해석 모듈 구축

Taehyun Kim1
,
Gwang-Il Kim1
,
Changsoo Lee2*
,
Jin-Seop Kim2
김 태현1
,
김 광일1
,
이 창수2*
,
김 진섭2
1Senior Researcher, Korea Atomic Energy Research Institute
2Principal Researcher, Korea Atomic Energy Research Institute
1한국원자력연구원 선임연구원
2한국원자력연구원 책임연구원
*Corresponding Author
30 April 2025. pp. 112-124
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Abstract

Buffer materials in a high-level radioactive waste disposal system serve as a key component of the engineered barriers by delaying radionuclide migration and protecting the disposal canister. Over extended periods, these buffer materials undergo a transition from an unsaturated to a saturated state under high-temperature conditions induced by radioactive decay heat and groundwater inflow from surrounding rock. The buffer materials exhibit swelling properties upon saturation, making it critical to predict the long-term capacity of swelling performance throughout the disposal period, which spans hundreds of thousands of years. In this study, the Barcelona Basic Model, a representative model for the elastoplastic behavior of unsaturated soils, was modularized within the thermo-hydro-mechanical coupled numerical simulator, OGS-FLAC3D. Following the construction of the numerical code, we conducted validation through comparative analysis with case studies evaluating volumetric changes along the pathways of mean effective stress and suction variations. The numerical simulation results and validation case studies showed a good agreement. Based on the developed module, we expect to use the OGS-FLAC3D simulator in various research studies related to the behavior of buffer materials in disposal systems.

Keywords
OGS-FLAC3D
Barcelona Basic Model
Elasto-Plastic behavior
Buffer material
Unsaturated soil

고준위 방사성폐기물 처분 시스템 내 완충재는 핵종 유출 시 이동을 지연하고 처분 용기를 보호하는 역할을 하는 공학적 방벽의 핵심 요소이다. 완충재에서는 방사성 붕괴열로 인한 고온 및 주변 암반으로부터의 지하수 유입 조건 하에서 장기간에 걸쳐 불포화 상태에서 포화 상태로 변화하는 과정을 거치게 된다. 완충재는 포화 시 팽윤하는 특성을 지니고 있으며 수십만 년에 이르는 처분 기간 동안 팽윤 성능 요건을 만족할 수 있는지 예측하는 것이 중요하다. 따라서 본 연구에서는 대표적인 불포화토의 탄소성 거동 모델인 Barcelona Basic Model을 열-수리-역학 복합거동 해석 시뮬레이터인 OGS-FLAC3D 내에 모듈화 하였다. 해석 코드 구축 후 검증을 위하여 평균 유효응력 및 흡입력 변화 경로에 따른 비체적 변화를 평가하는 예제와 비교 분석을 수행하였으며, 수치해석 결과 및 검증 예제 결과가 잘 일치하는 것을 확인하였다. 개발된 해석 모듈을 기반으로 향후 OGS-FLAC3D 해석 시뮬레이터를 처분 시스템 내 완충재 거동과 관련한 다양한 연구에 활용할 수 있을 것으로 기대된다.

키워드
OGS-FLAC3D
Barcelona Basic Model
탄소성 거동
완충재
불포화토
References
1

Alonso, E.E., Gens, A., and Josa, A., 1990, A constitutive model for partially saturated soils, Geotechnique, 40(3), 405-430.

10.1680/geot.1990.40.3.405
2

Börgesson, L., Chijimatsu, M., Fujita, T., Nguyen, T.S., Rutqvist, J., and Jing, L., 2001, Thermo-hydro-mechanical characterisation of a bentonite-based buffer material by laboratory tests and numerical back analyses, International Journal of Rock Mechanics and Mining Sciences, 38(1), 95-104.

10.1016/S1365-1609(00)00067-8
3

CODE BRIGHT, 2004, A 3D program for thermo-hydro-mechanical analysis in geological media manual, Barcelona, UPC.

4

Gens, A., 1995, Constitutive laws. In: Gens, A., Jouanna, P., Schrefler, B.A. (Eds.), Modern Issues in Non-saturated Soils, Springer-Verlag, New York, 129-158.

10.1007/978-3-7091-2692-9_2
5

Huertas, F., Fuentes-Cantillana, J.L., Jullien, F., Rivas, P., Linares, J., Fariña, P., Ghoreychi, M., Jockwer, N., Kickmaier, W., Martínez, M.A., and Samper, J., 2000, Full-scale engineered barriers experiment for a deep geological repository for high-level radioactive waste in crystalline host rock(FEBEX project), Final report, EUR(Luxembourg).

6

Itasca, 2012, FLAC3D Version 5.0, Fast Lagrangian Analysis of Continua in 3 Dimensions, Constitutive Models, Itasca Consulting Group, Minnesota.

7

Kim, T., Park, C.-H., Watanabe, N., Park, E.-S., Park, J.-W., Jung, Y.-B., and Kolditz, O., 2021a, Numerical modeling of two‑phase flow in deformable porous media: application to CO2 injection analysis in the Otway Basin, Australia, Environmental Earth Sciences, 80(121), 1-15.

10.1007/s12665-021-09411-1
8

Kim, T., C.-H. Park, C. Lee and J.-S. Kim, 2021b, A numerical study on the Step 0 benchmark test in Task C of DECOVALEX-2023: Simulation for thermo-hydro-mechanical coupled behavior by using OGS-FLAC, Tunnel & Underground Space, 31(6), 610-622.

9

Kim, T., Park, C.-H., Lee, C., Kim, J.-S., Park, E.-S., and Bastian, G., 2024, A numerical analysis of Thermo-Hydro-Mechanical behavior in the FE experiment at Mont Terri URL: Investigating capillary effects in bentonite on the disposal system, Geomechanics for Energy and the Environment, 40, 100597.

10.1016/j.gete.2024.100597
10

Kolditz, O, Bauer, S., Bilke, L., Böttcher, N., Delfs, J.O., Fischer, T., Görke, U.J., Kalbacher, T., Kosakowski, G., McDermott C C. et al., 2012, Opengeosys: an open-source initiative for numerical simulation of thermo-hydro-mechanical/chemical (thm/c) processes in porous media, Environmental Earth Sciences, 67(2), 589-599.

10.1007/s12665-012-1546-x
11

Komine, H., and Nobuhide, O., 1994, Experimental study on swelling characteristics of compacted bentonite, Canadian Geotechnical Journal, 31(4), 478-490.

10.1139/t94-057
12

Kristensson, O., and M. Ảkesson, 2008, Mechanical modeling of MX-80 - quick tools for BBM parameter analysis, Physics and Chemistry of the Earth, 33, 508-515.

10.1016/j.pce.2008.10.003
13

Lee, C., Lee, J., Kim, M., and Kim, G.Y., 2020, Implementation of Barcelona Basic Model into TOUGH2-MP/FLAC3D, Tunnel & Underground Space, 30(1), 39-62.

14

Lee, C., Yoon, S., Lee, J., and Kim, G.Y., 2019, Introduction of Barcelona Basic Model for Analysis of the Thermo-Elasto-Plastic Behavior of Unsaturated Soils, Tunnel & Underground Space, Vol. 29(1), 38-51.

15

Lee, D.-H., Go, G.-H., Lee, G.-J., and Yoon, S., 2024, Swelling behavior simulation study of KJ-II bentonite buffer blocks under various experimental conditions, Journal of the Korean Geotechnical Society, 40(2), 29-40.

16

Mašín, D., 2005, A hypoplastic constitutive model for clays, International Journal for numerical and analytical methods in Geomechanics, 29(4), 311-336.

10.1002/nag.416
17

Park, C.-H., Kim, T., Park, E.-S., Jung, Y.-B., and Bang, E.-S., 2019, Development and Verification of OGSFLAC Simulator for Hydro-mechanical Coupled Analysis: Single-phase Fluid Flow Analysis, Tunnel & Underground Space, 29(6), 468-479.

18

Park, C.-H., Kim, T., Park, E.-S., Jung, Y.-B., and Bang, E.-S., 2020, Construction of open-source program platform for efficient numerical analysis andits case study, Tunnel & Underground Space, 30(6), 509-518.

19

Park, D. and Park, C.-H., 2022, Performance evaluation of OGS-FLAC simulator for coupled thermal-hydrological-mechanical analysis, Tunnel & Underground Space, 32(2), 144-159.

20

Rutqvist, J., Ijiri, Y., and Yamamoto, H., 2011, Implementation of the Barcelona Basic Model into TOUGH-FLAC for simulations of the geomechanical behavior of unsaturated soils, Computers & Geosciences, 37, 751-762.

10.1016/j.cageo.2010.10.011
21

Shao, H., Rhoelke, C.h., Emmerich, K., Popp, T., Koeniger, F., Schuhmann, R., Wieczorek, K., and Hesser, J., 2024, Coupled hydromechanical modelling of a vertical hydraulic sealing system based on the sandwich principle, Rock Mechanics and Rock Engineering, 57(6), 4355-4365.

10.1007/s00603-023-03404-1
22

Wang, Q., Tang, A.M., Cui, Y.J., Delage, P., and Gatmiri, B., 2012, Experimental study on the swelling behaviour of bentonite/claystone mixture, Engineering Geology, 124, 59-66.

10.1016/j.enggeo.2011.10.003
23

Yoon, S. and Lee, G.-J., Chang, S., and Lee, D.-H., 2024, Assessment of thermal-hydraulic-mechanical-chemical (THMC) performances of Ca-type bentonite-graphite mixtures as buffer materials for a high-level radioactive waste repository, Case studies in Construction Materials, 21, e03876.

10.1016/j.cscm.2024.e03876
Information
  • Publisher :Korean Society for Rock Mechanics and Rock Engineering
  • Publisher(Ko) :한국암반공학회
  • Journal Title :Tunnel and Underground Space
  • Journal Title(Ko) :터널과 지하공간
  • Volume : 35
  • No :2
  • Pages :112-124
  • Received Date : 2025-04-08
  • Revised Date : 2025-04-11
  • Accepted Date : 2025-04-11
  • DOI :https://doi.org/10.7474/TUS.2025.35.2.112
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