Experimental study on dynamic mechanical properties of chemically corroded sandstone

In deep strata, there is a risk that geotechnical engineering is simultaneously subjected to chemical corrosion and dynamic loading, which seriously affects the safety of engineering. In this study, Split Hopkinson Pressure Bar (SHPB) was utilized to conduct dynamic loading tests on chemically corroded sandstone, which investigated the dynamic metamorphic properties and chemical damage of sandstone in this condition. Based on the effective bearing area and strain equivalence principles, the damage variables were determined by changes in the porosity of sandstone that were indicated by nuclear magnetic resonance (NMR). The microstructure and particle size distribution of sandstone were quantitatively analyzed by Scanning Electron Microscopy (SEM) and Nano Measurer software. Furthermore, the failure mechanisms of sandstone were explained by chemical reactions between rocks and solutions. The results showed that the porosity of sandstone corroded by chemical solutions increases. With the increase of damage variables, the dynamic compressive strength linearly decreases while the dynamic destructive strain gradually increases. The distribution of particle size has good self-similarity at the micro level and the fractal dimension was positively correlated with the damage variable. Microstructural metamorphism and chemical damage mechanisms of sandstones were revealed through microstructure testing and mineralization analysis. Findings are necessary for the safe operation of rock engineering.