In complex fractured porous media, geologic structure appears to play a key role in determining the direction and rate of transport as well as in controlling the rate of mass transfer between fractures and matrix pores. The complexity of geologic structures, such as these thinly-bedded heavily fractured soils underlying the Oak Ridge Reservation, presents a significant challenge for understanding and predicting the transport of contaminants through these materials. Controlled transport experiments using undisturbed soil materials ORNL researchers are conducting controlled transport experiments using undisturbed soil materials. The effluent is captured and analyzed for tracer concentrations. CAT scans of soil columns conducted at UT-Austin's High Resolution CT laboratory To determine the links between the fracture characteristics and transport behavior, CAT scans of soil columns are conducted at the University of Texas at Austin's High Resolution CT laboratory in order to image the internal structure of the columns.
CAT images represent density differences detected in slices through the column.
The images are processed to remove artifacts, and colors are assigned to density ranges to enhance visualization. 3D reconstruction of the column using CAT image data CAT image data are combined to produce a 3D reconstruction of the column that can then be interrogated by slicing the grid in various orientations. In this 3D rendering using a different color scheme, the fractures can be clearly identified. These reconstructions provide critical information about the structure and characteristics of the primary contaminant transport pathways in these materials.