Using CT-scanning to study internal erosion in soils

ABSTRACT: The decision to select a granular material as a construction material depends, in part, on its internal erosion susceptibility, particularly for embankment dams and dikes. The internal erosion (suffusion) is commonly determined by the application of empirical criteria based on the shape of the soil grain size distribution curve. A new analysis method, the X-ray micro Computed Tomography, can be used in addition to the conventional methods in order to determine the susceptibility of the specimens to internal erosion. Micro-CT images are capable of producing the 3D microstructure of the specimens before and after flow tests. Furthermore, micro-CT scans can provide insight into the porosity structure, grain size distribution and particle migration. This research looks into how micro-CT images of granular material can be obtained and analyzed as well as the limitations of such scans. Procedures are presented in order to avoid and reduce noise in micro-CT images and to obtain repeatable and reliable data from the specimens.