X-radiology and other forms of imaging have long played an important role in medical diagnosis. Recent developments in the past two decades of new and more powerful modalities for human imaging coupled with the explosive growth in the power of digital computers have dramatically changed the nature of radiological science. Applications of these new technologies present a new avenue of research in geotechnical and environmental engineering.
This study illustrates an example of the utilization of medical imaging techniques in geotechnical engineering for the examination of soil macro structure. X-ray radiography was utilized to study the changes in the macrostructure of fine-grained soils that resulted from freeze and thaw cycling. Freeze-and-thaw cycling changes the engineering properties of fine-grained soils (e.g., the hydraulic conductivity increases by one to three orders of magnitude.) In this study, laboratory compacted clay samples were examined using medical imaging before and after freeze and thaw cycling.
To evaluate the effects of freezing and thawing on the macrostructure of fine-grained soils, thin sections of frozen soil were also prepared at various freeze/thaw cycles and compared with unfrozen thin sections that were medically imaged. Thin sections of frozen fine grained soil were prepared using a milling machine in an environmental room. Macrostructure analyses of the thin sections were conducted by using back lighting which revealed details of the ice structures.