Abstract
To visualize in detail the manner of deformation in rocks under various confining and pore pressures, we used a micro focus X-ray CT system to obtain three dimensional image with high resolution of 5 micron. A new pressure vessel was developed to simultaneously supply both confining pressure and pore pressure to rock specimen. Berea sandstone and Noto diatomecious mudstone specimen of 10mm diameter and 20mm length were deformed hydrostatically. The diameters at every 15 degree angle were measured under the various conditions of confining and pore pressures. The average diameter decreased monotonically with increasing effective confining pressure, following the law of effective confining pressure. Sensitive orientation around the specimen diameter during pressurization was recognized, deformation anisotropy under pressurization then emerged and the fluctuation of diameter reached a maximum value of 8% in the case of Noto diatomecious mudstone. In this paper, we demonstrated deformation measurements by means ofmicro focus X-ray CT. This measurement method is applicable for deformation measurements of small and irregular rock specimen under various confining and pore pressures.
