A novel quantitative explanation for the fracture mechanism of sandstone containing a circular inclusion.

In this study, uniaxial compressive tests combined with the digital image correlation (DIC) method are used to investigate the mechanical properties, fracture process, and failure pattern of sandstone containing a circular inclusion. A DIC‐based methodology is proposed to quantitatively explain the crack initiation and propagation mechanism. The identification criterion of crack type is presented based on the nature of cracks and the development trends of relative displacement. Three crack types, including tensile cracks, tensile–shear cracks, and shear cracks, with different cracking mechanisms are identified. The inhibitory effect of the inclusions on crack initiation and propagation is revealed. The inclusion–matrix debonding mechanism is further investigated, and it is found that the inclusion interface consists of tensile concentration zones on the left/right sides and compressive concentration zones on the top/bottom sides. The tensile concentration zone is the main reason for debonding of the inclusions from the sandstone matrix. Highlights: The effect of an inclusion on opening‐containing sandstones is studied.A DIC‐based method to directly identify rock cracking properties is proposed.The crack types of the specimens under different filling conditions are identified.The inclusion–matrix debonding mechanism is quantitatively investigated. [ABSTRACT FROM AUTHOR]