Innovative Approach to Soil Characterization Using X-Ray Computed Tomography (CT): Fid-Bau Portal

Innovative Approach to Soil Characterization Using X-Ray Computed Tomography (CT)

Kibria, G. / Hossain, M. S. / Ali, A.

X-ray computed tomography (CT) is a new technology in the research arena of soil hydrophysical characteristics. It is a nondestructive method that has the ability to provide 3D images of soil samples. A large number of 2D parallel sections of the objects are obtained during tomography and, 3D images are reconstructed. A 3D image of soil sample can be utilized to determine the pore characteristics, internal structure, and moisture distribution. Therefore, hydrophysical characteristics of soil can be inferred from X-ray CT. The objective of the current study was to determine the proportion of voids and solids in soil samples and their relationship with electrical resistivity using conventional tests and X-ray CT. The soil sample was scanned at an isotropic voxel size of 20ìm in the eXplore Locus micro-CT scanner (GE Health Care). A total of six soil specimens were utilized in the current study to determine void ratio, degree of saturation, and moisture content. Phase relationship of soils obtained from conventional tests indicated that the void ratio and degree of saturation of the specimens ranged from 0.5 to 1.0 and 86% to 94%, respectively. X-ray CT scanning illustrated that the void ratio and degree of saturation of the samples ranged from 0.51 to 1.18 and 56% to 81%. Therefore, X-ray CT scanning predicted void ratios were in good agreement with conventional tests. However, the degrees of saturations, obtained from CT scanning were low compared with conventional test results. Soil resistivity tests were conducted on undisturbed soil samples at different drying stages. Resistivity results were plotted against the degree of saturations determined from conventional method and X-ray CT scanning. It was identified that the soil resistivity values were correlated with CT scanning results.