The disposal of nuclear waste in Germany targets deep rock formations acting as barriers over geological periods. The long-term protective effect of the geological barrier(s) depends on many factors, above all on geological processes. These processes often depend on the tectonic stress field, which is relevant not only to long-term stability but also for the construction of the underground repository. However, a reliable prognosis in the run-up to exploration measures is hindered by the fact that only few data are available and that the stress field is not uniform in its orientation and magnitude. In fact, significant local deviations from the supra-regionally known stress distribution can occur depending on the subsurface structure (lithologies, faults).
In order to improve the understanding of this spatial variability of the stress field, a geomechanical-numerical 3D stress model for Germany will be created in the SpannEnD project. This model will be generated by joining basement units (subproject TU Darmstadt) and overburden units (subproject KIT). It will be calibrated on in-situ measured stress data and allows forecasts for areas without stress data on the basis of continuum mechanical approaches. Furthermore, all six independent components of the stress tensor can be derived from the model. Since there is currently no database for stress magnitudes, such a database will be developed for Germany within the framework of the project.
In addition, modelling tools for models overlapping spatial scales will be developed. This allows a consistent transfer between the Germany model to partial models which are about three orders of magnitude smaller. All of these works provide necessary modelling tools for future geomechanical site models.