Dynamic compression and Brazilian disc tests were performed on dry, water- and brine-saturated sandstone with and without scCO 2 (supercritical carbon dioxide) injection. Split Hopkinson pressure bar (SHPB) tests were conducted under different strain rates. The full-field deformation and fracturing process were investigated by the high-speed 3D digital image correlation (DIC) technique with a resolution of 256 × 256 pixels at 200,000 frames per second (fps). The presence of CO 2 attenuated the dynamic compressive strength for dry and water-saturated sandstone. The dry sandstone has a greater brittleness with the saturation of CO 2 , but there was an opposite trend for water-saturated sandstone saturated by CO 2 . The presence of CO 2 had less effect on the dynamic mechanical properties on the brine-saturated sandstone. The normalised stress threshold for crack initiation became lower for the dry and water treated specimen but was less effective in brine-saturated sandstone. The injection of CO 2 intensified the fracturing degree, branching and altered the crack initiation position under dynamic loading. The mechanism of CO 2 effect was studied from mineralogical structure alteration based on the observation by scanning electron microscope (SEM).
|Number of pages||10|
|Journal||International Journal of Rock Mechanics and Mining Sciences|
|Publication status||Published - 1 May 2019|
- CO saturation
- Digital image correlation
- dynamic fracture
- Split Hopkinson pressure bar