Modelling advective gas flow in compact bentonite: lessons learnt from different numerical approaches
| Autor: | Jonny Rutqvist, N. Chittenden, Hua Shao, Ivan Puig Damians, Kunhwi Kim, E. Tamayo-Mas, Jaewon Lee, Y. Wang, Jon F. Harrington, Sebastià Olivella, T. Brüning, Elias Dagher, Olaf Kolditz, S.H. Lai |
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| Přispěvatelé: | Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental, Universitat Politècnica de Catalunya. MSR - Mecànica del Sòls i de les Roques |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Dilatant
Work (thermodynamics) Bentonite deposits Flow (psychology) 0211 other engineering and technologies Resources Engineering and Extractive Metallurgy Radioactive waste disposal in the ground Continuous approaches 02 engineering and technology Civil Engineering Bentonita -- Propietats Carbon capture and storage Gaseous diffusion Mining & Metallurgy Desenvolupament humà i sostenible::Enginyeria ambiental::Tractament dels residus [Àrees temàtiques de la UPC] Abocadors de residus radioactius 021102 mining & metallurgy 021101 geological & geomatics engineering Energies::Energia nuclear [Àrees temàtiques de la UPC] Petroleum engineering Advection Radioactive waste Geotechnical Engineering and Engineering Geology Gas flow Dilation Creep Environmental science Two-phase models Enginyeria civil::Geotècnia::Mecànica de sòls [Àrees temàtiques de la UPC] Fractures Mechanical deformation |
| Zdroj: | UPCommons. Portal del coneixement obert de la UPC Universitat Politècnica de Catalunya (UPC) Int. J. Rock Mech. Min. Sci. |
| Popis: | In a repository for radioactive waste hosted in a clay formation, hydrogen and other gases may be generated due to the corrosion of metallic materials under anoxic conditions, the radioactive decay of waste and the radiolysis of water. If the gas production rate exceeds the gas diffusion rate within the pores of the clay, a discrete gas phase will form and accumulate until its pressure becomes large enough to exceed the entry pressure of the surrounding material, at which point dilatant, advective flow of gas is expected to occur. The purpose of Task An under DECOVALEX-2019 is to better represent the processes governing the advective movement of gas in both low-permeability argillaceous repository host rocks and clay-based engineered barriers within numerical codes. In this paper special attention is given to the mechanisms controlling gas entry, flow and pathway sealing and their impact on the performance of the engineered clay barrier. Previous work suggests gas flow is accompanied by the creation of dilatant pathways whose properties change temporally and spatially within the medium. Thus, four new types of approaches have been developed: (i) standard two-phase flow models (continuous techniques) incorporating a range of different mechanical deformation behaviours, (ii) enhanced two-phase flow models in which fractures are embedded within a plastic material (continuous techniques) or incorporated into the model using a rigid-body-spring network (discrete approaches), (iii) a singlephase model incorporating a creep damage function in which only gas flow is considered, and (iv) a conceptual approach used to examine the chaotic nature of gas flow. The outputs from these different approaches are compared. This is an essential step as the choice of modelling approach strongly impacts the representation and prediction of gas flow in a future repository. In addition, experience gained through this task is of direct relevance to other clay-based engineering issues where immiscible gas flow is a consideration including hydrocarbon migration, carbon capture and storage, shale gas and landfill design. This paper summarises the outcomes of work in Task A conducted between May 2016 and May 2019 and provides a brief overview of the experimental data and a synthesis of the work of the participating modelling teams. DECOVALEX is an international research project comprising participants from industry, government and academia, focusing on development of understanding, models and codes in complex coupled problems in sub-surface geological and engineering applications; DECOVALEX-2019 is the current phase of the project. The authors appreciate and thank the DECOVALEX-2019 funding organisations Andra, BGR/UFZ, CNSC, US DOE, ENSI, JAEA, IRSN, KAERI, NWMO, RWM, SÚRAO, SSM and Taipower for their financial and technical support of the work described in this paper. The statements made in the paper are, however, solely those of the authors and do not necessarily reflect those of the funding organisations. |
| Databáze: | OpenAIRE |
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