Real-time evolution of oil shale meso-structure under triaxial stress condition

It is significant to research the mechanical properties and micro-fracture evolution characteristics of oil shales with different bedding directions under the condition of in-situ triaxial stress loading for understanding the internal micro-characteristics of oil shales. Triaxial stress loading tests of cylindrical oil shales were carried out in two loading directions perpendicular to and parallel to the bedding, which is the S1 and S2 samples. Our results demonstrate that the oil shales are typical anisotropic and brittle fracture characteristics. The triaxial compressive strength of S1 is higher than that of S2, but the elastic modulus is almost the same. Based on the reconstructed 3D-CT image, we analyzed the dynamic evolution law of the fracture inside the sample in the horizontal and vertical directions, and obtained the distribution of the fracture in the loading process, finally revealing the internal micro-characteristics of oil shales under the different loading conditions.