Voronoi 입자기반 개별요소모델을 이용한 암석 균열의 열에 의한 미끄러짐 해석: 국제공동연구 DECOVALEX-2023 Task G(Benchmark simulation)
Voronoi Grain-Based Distinct Element Modeling of Thermally Induced Fracture Slip: DECOVALEX-2023 Task G (Benchmark Simulation)
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초록
본 연구에서는 입자기반 개별요소모델(grain-based distinct element model, GBDEM)을 이용하여결정질 암석 내 포함된 균열의 열-역학적 거동을 평가할 수 있는 수치해석기법을 제시하고 열에 의한 균열의 미끄러짐 거동을 해석하였다. 이는 DECOVALEX-2023 프로젝트 Task G의 일환으로 수행된 벤치마크 모델링 연구로, Task G는 결정질 암반 내 균열의 열-수리-역학적 복합거동을 해석하기 위한 수치해석기법을 개발하는 데에 목표가 있다. 여기에서는 Voronoi diagram을 이용하여 다면체 개별입자의 집합체로서 해석모델을 생성하고, 입자 및 입자간 접촉에서 발생하는 열-역학적 거동을 개별요소프로그램인 3DEC을 통해 해석하였다. 암석 시험편의 탄성거동을 재현하기 위하여 등가연속체 개념을 적용하여입자와 접촉의 미시물성을 산정하였으며, 균열에 상응하는 접촉에는 Coulomb slip model을 부여하여인장강도와 전단강도를 갖는 불연속면을 모사하였다. 경계응력과 열응력에 의한 균열의 거동을 수치적으로 모델링하였으며, 경계조건에 따라 균열의 미끄러짐이 발생하는 열-역학적 메커니즘을 정량적으로분석하였다. 해석 결과, 본 연구에서 제시한 해석모델이 암석 내 열팽창과 열응력의 증가, 균열 응력과 변위, 경계조건의 영향 등을 합리적으로 재현하고 있음을 확인하였다. 본 연구의 해석모델은 Task G에 참여하는 국외 연구팀들과의 의견 교류와 워크숍을 통해 지속적으로 개선하는 한편, 향후 실내실험에 적용하여 타당성을 검증할 예정이다.
Abstract
We proposed a numerical method for the thermo-mechanical behavior of rock fracture using a grain-based distinct element model (GBDEM) and simulated thermally induced fracture slip. The present study is the benchmark simulation performed as part of DECOVALEX-2023 Task G, which aims to develop a numerical method to estimate the coupled thermo-hydro-mechanical processes within the crystalline rock fracture network. We represented the rock sample as an assembly of Voronoi grains and calculated the interaction of the grains (blocks) and their interfaces (contacts) using a distinct element code, 3DEC. Based on an equivalent continuum approach, the micro-parameters of grains and contacts were determined to reproduce rock as an elastic material. Then, the behavior of the fracture embedded in the rock was characterized by the contacts with Coulomb shear strength and tensile strength. In the benchmark simulation, we quantitatively examined the effects of the boundary stress and thermal stress due to heat conduction on fracture behavior, focusing on the mechanism of thermally induced fracture slip. The simulation results showed that the developed numerical model reasonably reproduced the thermal expansion and thermal stress increment, the fracture stress and displacement and the effect of boundary condition. We expect the numerical model to be enhanced by continuing collaboration and interaction with other research teams of DECOVALEX-2023 Task G and validated in further study experiments.
참고문헌 (18)
- Fu, T. F, "Mesoscopic time-dependent behavior of rocks based on three-dimensional discrete element grain-based model", Computers and Geotechnics, 121, pp.103472~ (2020)
- Geuzaine, C, "Gmsh : A 3-D finite element mesh generator with built-in pre-and post-processing facilities", International journal for numerical methods in engineering, 79(11), pp.1309~1331 (2009)
- Ghazvinian, E, "3D random Voronoi grain-based models for simulation of brittle rock damage and fabric-guided micro-fracturing", Journal of Rock Mechanics and Geotechnical Engineering, 6(6), pp.506~521 (2014)
- IAEA, "Geological disposal facilities for radioactive waste" (2011), IAEA
- "3DEC (3 Dimensional Distinct Element Code) online manual" (2021)[URL]
- Jaeger, J.C, "Fundamentals in Rock Mechanics" (2007), Blackwell publishing
- Birkholzer, J. T, "25 years of DECOVALEX-Scientific advances and lessons learned from an international research collaboration in coupled subsurface processes", International Journal of Rock Mechanics and Mining Sciences, 122, pp.103995~ (2019)
- 김태현, "고준위방사성폐기물 처분장 내 열-수리-역학-화학적 복합거동 해석을 위한 국제공동연구 DECOVALEX-2023에서 수행 중인 연구 과제 소개", 터널과 지하공간, 31(3), pp.167~183 (2021), 한국암반공학회
- Lan, H. X, "Effect of heterogeneity of brittle rock on micromechanical extensile behavior during compression loading", Journal of Geophysical Research: Solid Earth, 115(B1) (2010)
- Lee, C, "Numerical analysis of coupled thermo-hydro-mechanical behavior in single-and multi-layer repository concepts for high-level radioactive waste disposal", Tunnelling and Underground Space Technology, 103, pp.103452~ (2020)
- Lee, J, "Concept of a Korean reference disposal system for spent fuels", Journal of Nuclear Science and Technology, 44(12), pp.1565~1573 (2007)
- Park, J. W, "Polygonal grain-based distinct element modeling for mechanical behavior of brittle rock", International Journal for Numerical and Analytical Methods in Geomechanics, 41(6), pp.880~898 (2017)
- 박정욱, "입자기반 개별요소모델을 이용한 암석 균열의 수리역학 거동해석: 국제공동연구 DECOVALEX-2023 Task G (Benchmark Simulation)", 터널과 지하공간, 31(4), pp.270~288 (2021), 한국암반공학회
- 박정욱, "입자기반 개별요소모델을 통한 결정질 암석 내 균열의 역학적 거동 모델링: 국제공동연구 DECOVALEX-2023 Task G(Benchmark Simulation)", 터널과 지하공간, 30(6), pp.573~590 (2020), 한국암반공학회
- Quey, R, "Large-scale 3D random polycrystals for the finite element method: Generation, meshing and remeshing", Computer Methods in Applied Mechanics and Engineering, (17-20), pp.1729~1745 (2011)
- Sun, C, "hermally induced slip of a single sawcut granite fracture under biaxial loading", Geomechanics and Geophysics for Geo-Energy and Geo-Resources, 7(4), pp.1~13 (2021)
- Wang, Z, "Investigation of microcracking behaviors in brittle rock using polygonal grain‐based distinct method", International Journal for Numerical and Analytical Methods in Geomechanics (2021)
- Zoback, M.D, "Earthquake triggering and large-scale geologic storage of carbon dioxide", Proceedings of the National Academy of Sciences of the United States of America, 109(26), pp.10164~10168 (2012)