Investigation on Mechanical and Failure Characteristics of Sandstone with Flaw.

To quantitatively study the instability and failure characteristics of sandstone with flaws under engineering load, a method for identifying the failure characteristics of rock mass with flaws by date based on Digital image correlation (DIC) technology is proposed. The crack initiation type, corresponding action sequence, and stress level are determined. The uniaxial compression tests of sandstone with a prefabricated flaw at different angles are carried out. And the mechanical properties and deformation field characteristics, and failure characteristics of sandstone with flaws are analyzed. The results show that the peak strength and elastic modulus of sandstone increase and the damage propagation behavior decrease with the increase of flaw angle. Based on DIC technology, the whole process of crack initiation, propagation, and failure is intuitively reflected, the deformation characteristics corresponding to the stress levels of the 4 key points are clarified, and the crack propagation path and key failure areas are mastered. The flaw inclination angle affects the distribution of displacement and strain and determines the new crack initiation position. With the increase of stress value, the horizontal displacement and principal strain increase exponentially at different angles, and the vertical displacement increase linearly. When the inclination angle is 30°, 45°, and 60°, the strain distribution along the crack tip is "Butterfly". The fracture initiation modes of sandstone with a prefabricated flaw at different angles include type I and I–II mixed type. In type I–II, type II acts before type I, and the stress level is lower than type I. [ABSTRACT FROM AUTHOR]