Frequency Spectrum and Damage Characteristics of Saturated and Dry Red Sandstone Subject to Shear Test

The signal of acoustic emission (AE) captured during the sandstone shear failure is the key information to ascertain the damage degree (DD) of rock. To reveal the frequency spectrum and damage characteristics of saturated-and-dry red sandstone, the AE parameters of saturated-and-dry red sandstone such as cumulative energy, cumulative ring counts, the dominant and secondary frequencies (DSF) were analyzed during shear test by using AE monitoring technique. Results show that the shear damage stress of red sandstone is determined according to the cumulative energy and cumulative ring counts curves. The DD is expressed via cumulative ring counts and the relationship between DD and shear strain is established. DSF of red sandstone in saturated-and-dry state decrease when normal stress increases. The conclusion obtained in this study is of very important theoretical significance to determine shear DD of red sandstone.