Influence of CT scanning parameters on rock and soil images

Abstract

Geotechnical mechanical testing machine is an important means to study the characteristics of rock and soil rupture, which is of great significance in shale gas exploitation, nuclear waste disposal and earthquake prediction. For the convenience of research, the complex structure of rock and soil is often neglected, and the geotechnical material is regarded as a macro continuum. On this basis, a new method is used, X-ray CT scale cracks, crack size is larger than the micro-scale cracks, the number of cracks is less, but geotechnical CT images can still show the crack initiation location, propagation path, through the process, cracks and the relationship between aggregate mortar. When CT-scale microcracks can be found, the length of microcracks is equal to the magnitude of aggregate-scale, and can be compared with numerical simulation results. In this paper, four different kinds of soil samples are selected to design relevant tests. The specific effects of CT scanning parameters on CT images of rock and soil samples are studied by direct and indirect methods combined with CT number curves under different scanning conditions. The results show that the scanning voltage and filtering function have great influence on CT images and CT numbers of rock and soil samples. The enhancement or inhibition of the filtering function to the geotechnical CT image depends on the property of the selected filtering function, but has nothing to do with the soil quality of the sample. Finally, the selection principle of the CT scanning parameters is given. With the help of reasonable CT scanning parameters, the quality of the geotechnical CT image can be improved and the relatively accurate geotechnical CT value can be obtained.