Dynamic mechanical properties and fractal characteristics of layered sandstone under chemical corrosion

To investigate the dynamic mechanical behavior and fragmentation characteristics of layered rock under the combined effects of chemical corrosion and impact loading, split Hopkinson pressure bar (SHPB) tests were performed on layered sandstone specimens with bedding angles of 0°, 30°, 45°, 60°, and 90°. The tests were conducted under solutions with various pH levels and under multiple impact pressure conditions. Stress–strain responses, strength and deformation parameters, and failure modes were analyzed to evaluate the anisotropy in mechanical behavior. Fragment size distribution was systematically examined using fractal theory to quantify the degree of fragmentation. The results show that the dynamic compressive strength exhibits U-shaped anisotropy, which is significantly intensified by chemical corrosion. Strength degradation was most pronounced under acidic conditions (pH = 4), followed by alkaline (pH = 10) and neutral (pH = 7) environments, with the greatest reduction observed at bedding angles of 45° and 60°. Both dynamic strength and peak strain increase with rising impact pressure, whereas the influence of chemical corrosion gradually diminishes. The fractal dimension also increases with impact pressure, but at a declining rate. Acidic conditions led to the highest fractal dimension, reflecting more intense fragmentation. These findings provide valuable insights for disaster prevention and the optimization of fragmentation efficiency in engineering practices involving chemically corroded layered rock masses.