Mechanical properties and acoustic emission characterization of red sandstone with cross-fractures

Abstract

To investigate the mechanical behavior and responses under loading, energy dissipation, and crack propagation in rocks with cross-fractures, this study prepared rock specimens with varying angles of cross-fractures and conducted uniaxial loading tests combined with acoustic emission monitoring to obtain mechanical parameters and acoustic emission characteristics. The experimental results demonstrate that cross-fractures significantly influence the stress–strain curves and mechanical properties of rocks, particularly at fracture angles of 30° and 60°, where pronounced stress drops and local damage phenomena are observed. Energy analysis demonstrates that the specimen with 90° cross fractures possesses the highest capacity for elastic strain energy accumulation, with a peak value of 58.43 KJ·m −3 , while the 30° fractured specimen exhibits the weakest energy storage capacity, reaching a peak of only 31.20 KJ·m −3 . For the 45° fractured specimen, elastic strain energy accounts for merely 70.49% of the total absorbed energy, indicating more sufficient plastic deformation; more work input from external loading is dissipated in the form of plastic damage. Prior to failure, crack propagation triggers a rapid release of elastic strain energy and a dramatic increase in dissipated energy. The acoustic emission ringing count and spatial location maps of events uncover the propagation process of internal cracks in the rocks, which become more pronounced as the degree of rock damage increases. These findings offer a theoretical foundation for the prediction of engineering disasters associated with fractured rocks in the fields of geology and petrology.