Study on coupled thermo-hydro-mechanical processes in column bentonite test
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An unconventional numerical scheme is developed to simulate coupled thermo-hydro-mechanical (THM) processes in partially saturated medium. The non-isothermal, unsaturated fluid flow and mechanical processes are sequentially coupled by updating all the state variables using cellular automaton technique and finite difference method on spatial and temporal scale, respectively. A new cellular automaton updating scheme is proposed by introducing a fast successive relaxation index, which greatly improves the computational efficiency in the simulation of THM coupling process. This is implemented in a self-developed numerical system, i.e., an elasto-plastic cellular automaton (EPCA3D), which was used to numerically reproduce the coupled THM behavior of bentonite pellets in a column experiment that was heated up to 140 °C firstly and then was hydrated simulating the resaturation of the backfilling. By using the cellular automaton technique in EPCA3D, the challenging courses of the changing boundary conditions over time and space during the experiment are conveniently implemented. The EPCA3D was able to reproduce the main physical processes of the in laboratory column bentonite experiment within the heating and hydration phase. The modeling results for the evolution of temperature, relative humidity, water uptake and axial pressure are consistent with the experimental data in terms of trends and magnitudes, which verifies the realistic simulation with the developed model and contributes to a deeper understanding of the observed phenomena.
KeywordsCoupled thermo-hydro-mechanical process Non-isothermal Unsaturated flow Bentonite pellets EPCA3D Fast successive relaxation method
This work was finically supported by international cooperation project of Chinese Academy of Sciences (Nos. 115242KYSB20160017, 115242KYSB20160024), and the Key Research Program of Frontier Sciences, CAS (No. QYZDB-SSW-DQC029).
- Arifin YF (2008) Thermo-hydro-mechanical behavior of compacted bentonite-sand mixtures: an experimental study. Bauhaus-University Weimar, WeimarGoogle Scholar
- Gaus I, Garitte B, Senger R, Gens A, Vasconcelos R, Garcia-Sineriz J, Trick T, Wiecozorek K, Czaikowski O, Schuster K (2014) The HE-E experiment: lay-out, interpretation and THM modelling. NAGRA Arbeitsbericht NAB 14–53Google Scholar
- Johnson L, Niemeyer M, Klubertanz G, Siegel P, Gribi P (2002) Calculations of the temperature evolution of a repository for spent fuel, vitrified high-level waste and intermediate level waste in Opalinus Clay. Nagra, WettingenGoogle Scholar
- Li L, Liu H (2013) A numerical study of the mechanical response to excavation and ventilation around tunnels in clay rocks. Int J Rock Mech Min Sci 59:22–32Google Scholar
- Mueller HR, Weber HP, Koehler S, Vogt T (2012) The full-scale Emplacement (FE) Experiment at the Mont Terri URL. Clays in natural and engineered barriers for radioactive waste confinement—5 international meeting book of abstracts, France, p 923Google Scholar
- Rizzi M, Seiphoori A, Ferrari A, Ceresetti D, Laloui L (2011) Analysis of the behaviour of the Granular MX-80 bentonite in THM-processes. Lausanne Swiss Fed Inst Technol Orders 7:928Google Scholar
- Sugita Y, Kwon S, Lee C, Massmann J, Pan P, Rutqvist J (2016) DECOVALEX-2015 project Task B2 final report, StockholmGoogle Scholar
- Tadano H, Sakurai T (2008) On single precision preconditioners for Krylov subspace iterative methods. In: Large-scale scientific computing: 6th international conference, LSSC 2007, Sozopol, Bulgaria, June 5–9, 2007. Revised papers. I. Lirkov, S. Margenov and J. Waśniewski. Springer Berlin, Heidelberg, pp 721–728Google Scholar
- Villar MV, Martín PL, Gómez-Espina R, Romero FJ, Barcala JM (2012). THM cells for the HE-E test: setup and first results. PEBS report D2.2.7a. CIEMAT technical report, CIEMAT/DMA/2G210/02/2012, Madrid, p 34Google Scholar
- Wieczorek K, Miehe R, Garitte B (2011) Measurement of thermal parameters of the HE-E buffer materials. PEBS Deliv D 2:2–5Google Scholar