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
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.