This study conducts a numerical analysis of long-term thermo-hydromechanical (THM) processes, with a particular focus on deep geological disposal of radioactive waste. It emphasizes the modeling of damage zones resulting from excavation activities, as well as changes in pore pressure and temperature. The numerical model presented in this paper delineates the fundamental relations of thermo-poro-elasticity. It also introduces a double phase field model specifically formulated for rock materials under compressive stress, taking into account THM coupling and time-dependent behavior. The proposed model has been implemented in a finite element code and applied to numerical analysis of short and long terms responses around a horizontal borehole in the context of the French High-Level Waste (HLW) disposal concept. In particular, displacements, temperature changes, pore fluid pressure variations as well as evolution of induced damage zones are presented and analyzed for different periods including excavation, operation and post-closure. It is found that the occurrence of damage zones is clearly related to the spacing distance between two neighboring disposal boreholes. The time-dependent deformation of host rock plays an significant role in the long-term responses.

中文翻译：

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热流机械损伤模型及其在深层地质放射性处置库中的应用

这项研究对长期热流体机械（THM）过程进行了数值分析，特别关注放射性废物的深层地质处置。它强调对开挖活动造成的损坏区域以及孔隙压力和温度的变化进行建模。本文提出的数值模型描述了热孔隙弹性的基本关系。它还引入了专为压应力下岩石材料制定的双相场模型，同时考虑了 THM 耦合和时间相关行为。所提出的模型已在有限元代码中实施，并应用于法国高放废物（HLW）处置概念背景下水平钻孔周围短期和长期响应的数值分析。特别是，对不同时期（包括开挖、运营和关闭后）的位移、温度变化、孔隙流体压力变化以及诱发损伤区的演变进行了呈现和分析。研究发现，损伤区的出现与相邻两个处置钻孔之间的间距有明显的关系。主岩随时间变化的变形在长期响应中起着重要作用。