Numerical simulation of solute transport in argillaceous rock under thermal gradient with a coupled THM-solute transport model

IF 3.3 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment Pub Date : 2024-12-27 DOI:10.1016/j.gete.2024.100632

Uy Vo , Mamadou Fall , Julio Ángel Infante Sedano , Maïwenn Humbezi-Desfeux , Jean-Michel Matray , Manuel Marcoux , Thanh Son Nguyen

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引用次数: 0

Abstract

Argillaceous rocks have many favourable characteristics for deep geological disposal of high-level radioactive waste (HLW) such as low permeability resulting in slow solute transport dominated by diffusion processes. However, waste-generated heat can increase pore pressure through Thermal-Hydraulic-Mechanical (THM) coupled processes, potentially enhancing advective transport. In this study, the authors developed a mathematical model to simulate a laboratory and a large-scale in situ experiment at an underground research facility (URF), to investigate (1) T-solute transport coupling (via the Soret effect and temperature-dependent diffusion coefficient) and (2) THM-solute transport coupling in argillaceous rock. The findings suggest that the Soret effect is significant in the laboratory experiments with relatively high thermal gradient, but negligible in the URF experiment where the thermal gradient is much smaller. Instead, the effect of temperature on the diffusion coefficient appears to play a more crucial role for the URF experiment. In addition, the advection enhancement due to thermal pressurization as a result of THM processes shows an insignificant effect on solute transport. The modelling of the URF experiment, as confirmed by observational evidence, shows the importance of anisotropy of the THM-transport properties as well as the effects of the excavation damage zone (EDZ). Finally, the model captures the key features of both experiments, highlighting its capability in enhancing comprehension of transport processes from a deep geological repository (DGR) built in argillaceous rocks. This improved understanding is valuable for safety assessments of DGRs in such rock types.

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来源期刊

Geomechanics for Energy and the Environment Earth and Planetary Sciences-Geotechnical Engineering and Engineering Geology

CiteScore

5.90

自引率

11.80%

发文量

期刊介绍： The aim of the Journal is to publish research results of the highest quality and of lasting importance on the subject of geomechanics, with the focus on applications to geological energy production and storage, and the interaction of soils and rocks with the natural and engineered environment. Special attention is given to concepts and developments of new energy geotechnologies that comprise intrinsic mechanisms protecting the environment against a potential engineering induced damage, hence warranting sustainable usage of energy resources. The scope of the journal is broad, including fundamental concepts in geomechanics and mechanics of porous media, the experiments and analysis of novel phenomena and applications. Of special interest are issues resulting from coupling of particular physics, chemistry and biology of external forcings, as well as of pore fluid/gas and minerals to the solid mechanics of the medium skeleton and pore fluid mechanics. The multi-scale and inter-scale interactions between the phenomena and the behavior representations are also of particular interest. Contributions to general theoretical approach to these issues, but of potential reference to geomechanics in its context of energy and the environment are also most welcome.