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Effects of changing boundary conditions on the development of hydrogeological systems: Numerical long-term modelling under consideration of thermal-hydraulic-mechanical (-chemical) coupled effects

 

Short summary of the project:

Within the context of the Federal Waste Management Act on the Search and Selection of a Site for a Repository for the Safe Custody of High-Level Radioactive Waste (StandAG), the geoscientific and planning requirements and criteria are specified. The necessary considerations include the modelling of hydrogeological scenarios such as future cold and warm periods with the associated icing events, which can significantly alter the (petro)physical and hydrogeological properties of the overall system and its boundary conditions.

The AREHS project's main target is to model the effects of changing external environmental conditions on the hydrogeologically relevant parameters (e.g. hydraulic permeability, porosity, migration paths, fluid availability, hydraulic gradients) of a potential geological repository in Germany (clayey rock, rock salt, crystalline rock) and its surrounding rock units. Special attention is paid to the cyclical mechanical loading and unloading due to icing events and the resulting stress changes (M) and induced temperature effects (T) due to permafrost and warm periods. Since such processes can cause changes in the coupled far-field regime with groundwater flow and groundwater availability (H) as well as fluid transport due to thermal (T) and chemical (C) gradients and can reactivate disturbances/cracks (M) and thus create new/additional pathways, they are particularly relevant for the integrity of a repository over a period of 1 million years and must be properly determined with coupled THM (C) modelling. OpenGeoSys is used and further developed as a numerical platform.

 

Project period:

03/2020 – 11/2022

Project Funding:

Federal Office for the Safety of Nuclear Waste Management  (BASE)

 Projekt partners:

  • G.E.O.S. Ingenieurgesellschaft mbH
  • ERCOSPLAN Ingenieurgesellschaft Geotechnik und Bergbau mbH
  • Helmholtz-Zentrum für Umweltforschung GmbH UFZ
  • TU Bergakademie Freiberg (TUBAF)