Determining Geometric Grain Structure from X-Ray Micro-Tomograms of Gradated Soil

We present a method to determine the geometric grain structure of gradated soil by means of X-ray micro-computed tomography and image processing. High-resolution tomographic images are acquired of sample material that is embedded in epoxy resin. Position and shape of coarseand medium-sized grains are computed by applying morphologic image operators. We compare the results of image processing with the grain size distribution measured by sieving. First results indicate that our method has the potential of analysing the structure formed by grains of size 1 mm to 20 mm, although more data are needed to confirm this statistically. Our findings suggest that computed tomography in combination with automatic image processing methods can deliver geometric parameters of real grain and pore structure suitable for analysing suffosive erosion phenomena.