ARTYKUŁY NAUKOWE Możliwoości wykorzystania wysokorozdzielczej mikrotomografii komputerowej w badaniach geologiczno-inżynierskich na przykładzie analizy iłów mio-plioceńskich
Abstract
The possibility of using high-resolution X-ray computed microtomography in engineering geology analysis, based on a study of Mio-Pliocene clays.
A b s t r a c t. The paper considers the use of high-resolution X-ray computed microtomography (μCT) as a possible method in engineering-geological laboratory research for indicating areas of weakness, location of fissures and determining homogeneity of clay samples. Furthermore, the studies were used to provide methodological guidance. Mio-Pliocene (Neogene) clay samples were taken from an excavation site of the Kopernik underground station in Warsaw. First, natural humidity, bulk density and fraction analyses of samples were made. Secondly, μCT scans were conducted, with the use of copper filters. In the final stage of the study, internal structure images for samples were processed and analysed. Furthermore, a numerical model of dry sample was developed. During the study it was observed that the increase of temperature caused by X-ray radiation has a destructive effect on the sample. This effect was eliminated by applying a protective layer on the sample, using engine oil. The article quantifies the ratio of radiation-heated fissure volume to dry sample volume and the natural fissure volume to sample volume. Moreover, sample areas with different densities or chemical composition were studied. The results lead to the conclusion that the μCT technique is applicable to characterise of Mio-Pliocene clay, supplying internal structure assessment and fissure quantification that allow for samples verification to further engineering geology in-depth analysis.
A b s t r a c t. The paper considers the use of high-resolution X-ray computed microtomography (μCT) as a possible method in engineering-geological laboratory research for indicating areas of weakness, location of fissures and determining homogeneity of clay samples. Furthermore, the studies were used to provide methodological guidance. Mio-Pliocene (Neogene) clay samples were taken from an excavation site of the Kopernik underground station in Warsaw. First, natural humidity, bulk density and fraction analyses of samples were made. Secondly, μCT scans were conducted, with the use of copper filters. In the final stage of the study, internal structure images for samples were processed and analysed. Furthermore, a numerical model of dry sample was developed. During the study it was observed that the increase of temperature caused by X-ray radiation has a destructive effect on the sample. This effect was eliminated by applying a protective layer on the sample, using engine oil. The article quantifies the ratio of radiation-heated fissure volume to dry sample volume and the natural fissure volume to sample volume. Moreover, sample areas with different densities or chemical composition were studied. The results lead to the conclusion that the μCT technique is applicable to characterise of Mio-Pliocene clay, supplying internal structure assessment and fissure quantification that allow for samples verification to further engineering geology in-depth analysis.