Strukturuntersuchungen zur Charakterisierung der ungesättigten Wasserströmung in porösen Medien

The physical determination of the hydraulics of the vadose zone in
sediments and porous building-materials is the basis of the
calculation and modelling of fluid, pollutant and heat transport.
Here the pore size distribution and the heterogeneous structure of
the pore space play a decisive role as an input parameter.
Parameters of the hydraulics and unsaturated flow of sediment
bodies were obtained by desorption and tank experiments and
represented in two-dimensional visualizations. The experimental
setup contained a two-dimensional measurement of the hydraulic
potential and the distribution of the electrical conductivity
during different stationary and dynamic flow processes. These
experiments, along with the application of visual methods by means
of tomography and image analysis, allowed for new approaches for
the detection of the pore space properties and its heterogeneities:
The hydraulic laboratory experiments identified a variation of the
flow parameters in homogeneous sediment bodies. Optical methods
demonstrated through the non-destructive process of the tomography
a future practical strategy for undisturbed probes since great
development potentials of the optical resolution are still
physically possible opposite the used x-ray scanner. By contrast,
the image analysis of scanned polished sections is connected to a
sample treatment, but stands out due to a high degree of automation
and low costs. The application of the different methods could
represent the correlation of pore space structure and hydraulic
properties. Due to the visual methods the complex structural
properties are received quickly andversatilely. So the pore size
distribution and the sum of the grain surfaces could be detected
among other things. From this, a numeric model approach could be
developed for the hydraulic properties and the moisture transport
of porous media.