Study on the anisotropic mechanical properties of bedding sandstone under acid corrosion

To investigate the effects of acid corrosion on the mechanical properties of sandstone with varying bedding angles, uniaxial compression tests were conducted under different acidic environments and bedding angles, combined with acoustic emission (AE) monitoring. The anisotropic characteristics of sandstone, including strength, deformation, brittleness, and failure modes, were analyzed, and a uniaxial compressive strength model for sandstone under varying acidic conditions and bedding angles was established. The results indicate that: (1) as the bedding angle increases, the peak strength of sandstone initially decreases and then increases, while the elastic modulus generally increases, and Poisson's ratio exhibits a trend of first increasing, then decreasing, and finally increasing. (2) With increasing acidity of the soaking solution, both the peak strength and elastic modulus decrease, while Poisson's ratio increases, indicating enhanced anisotropic characteristics in the strength and deformation of sandstone. (3) A predictive model for the uniaxial compressive strength of intact rock under different acidic environments was proposed, alongside a uniaxial compressive strength model for sandstone incorporating both acidity and bedding angle effects. (4) The failure modes of sandstone vary significantly with bedding angle. At bedding angles of 30°, 45°, and 60°, sandstone exhibits lower brittleness and is more susceptible to shear failure. Additionally, increased acidity reduces the brittleness of the samples, with AE counts transitioning from low-frequency high peaks" to "high-frequency low peaks". The dominant failure mode shifts from splitting failure to shear failure as acidity intensifies. These findings provide a reference for analyzing the stability and deformation behavior of rock engineering in regions affected by acidic mine drainage. © 2024 Editorial Office of Journal of Mining and Strata Control Engineering. All rights reserved."