Relevance of adopting a double porosity retention curve for modelling bentonite hydration under high temperature conditions

IF 3.3 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment Pub Date : 2025-05-13 DOI:10.1016/j.gete.2025.100684

Laura Asensio, Gema Urraca, Vicente Navarro

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引用次数: 0

Abstract

This study aims to gain a better understanding of the coupled thermo-hydraulic effects of the water retention formulation in compacted bentonites, and especially of a double porosity formulation. To this end, several thermo-hydraulic laboratory tests have been simulated with a thermo-hydro-mechanical model using three different water retention formulations: single porosity, single porosity with temperature dependence and double porosity. The results indicate that the impact of including temperature dependence in a single porosity model is limited. In addition, for the case that combines intense heating (150 ºC) with hydration, only the double porosity model produced quality results, even if it did not include a direct dependence on temperature. Differentiation between microstructural and macrostructural water is key to reproducing the thermally induced drying and exhaustion of the flow channels observed in these conditions and not under moderate heating. Therefore, double porosity formulations for the water retention behaviour of bentonites are especially advisable to represent the coupled thermo-hydraulic effects in conditions combining intense heating with hydration, as in deep geological repositories of spent nuclear fuel.

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采用双孔隙率保留曲线模拟高温条件下膨润土水化的相关性

本研究旨在更好地理解压实膨润土中保水配方，特别是双孔隙配方的热-水力耦合效应。为此，采用三种不同的保水配方（单孔隙度、单孔隙度与温度相关以及双孔隙度），用热-水-力学模型模拟了几项热-水实验室试验。结果表明，在单一孔隙度模型中加入温度依赖性的影响是有限的。此外，对于将高温（150℃）与水化相结合的情况，只有双重孔隙率模型产生了高质量的结果，即使它不包括对温度的直接依赖。微观结构水和宏观结构水之间的区别是重现在这些条件下而不是在适度加热下观察到的热致干燥和流道枯竭的关键。因此，对于膨润土的保水行为，双孔隙率公式特别适用于在强烈加热与水化相结合的条件下，如在乏核燃料的深层地质储存库中，表现耦合的热-水力效应。

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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.