Research on Brazilian splitting mechanics and acoustic emission characteristics of various types of sandstones in Shendong mining area

In order to investigate the tensile mechanical properties of various sandstones in the Shendong mining area, real-time acoustic emission (AE) monitoring of Brazilian fracturing was conducted. Through AE monitoring tests, the tensile strength, fracture toughness, peak energy rate, failure mode, as well as the characteristics of AE and the evolution of damage variables were analyzed during the splitting process. The research results show that the average tensile strength of argillaceous siltstone, calc-argillaceous siltstone, argillaceous fine sandstone, calc-argillaceous coarse sandstone, and calcareous coarse sandstone are 5.72, 6.92, 2.71, 1.39, and 13.20 MPa, respectively. The average fracture toughness are 1.11, 1.00, 0.71, 0.38, and 0.81 MPa m^1/2, and the average peak energy efficiency are 1577.8, 2099.0, 1313.0, 233.5, and 4125.8 J m^-2, respectively. The failure modes of various types of sandstones can be categorized as linear (argillaceous siltstone, argillaceous fine sandstone), arc-shaped (cal-argillaceous siltstone, calc-argillaceous coarse sandstone), and ""-shaped (calcareous coarse sandstone). In the case of siltstone, the AR (the ratio of AF (AE ring count/duration time) to RA (rise time/amplitude)) values for acoustic emission are evenly distributed, resulting in a linear growth pattern in the overall damage curve. For argillaceous fine sandstone and cal-argillaceous coarse sandstone, the AR value distribution is dense, leading to an S-shaped growth in the overall damage curve. In contrast, the AR value distribution for calcareous coarse sandstone is sparse, resulting in an L-shaped growth in the overall damage curve. The research results can be a reference for the mechanical property of weakly cemented sandstone and provide valuable insights for optimizing mining operations in the Shendong mining area.