Effects of Acid Environment on Mechanical Properties of Cemented Tailings Backfill

The characteristics of cemented tailings backfill (CTB) in the underground acidic environment under the corrosion of sulfuric acid solution were studied. The parameters were tested and analyzed, including uniaxial compressive strength (UCS), elastic modulus, cohesion, internal friction angle. In addition the XRD analysis and electron scanning of the surface material of CTB was carried out, and the sulfuric acid corrosion mechanism of CTB was discussed. The research results showed that the changes of UCS, elastic modulus and cohesion over time are approximately the same under the corrosion of sulfuric acid solution, all showing a trend of increasing first and then decreasing. The internal friction angle presents a volatility downward trend. Sulfuric acid solution corrosion has an effect on the mechanics of CTB, although it is beneficial to the strength of CTB in the early stage and unfavorable in the long term. Regardless of whether the initial solution is strong acid or weakly acidic, the pH of the solution tends to be neutral. The mechanism of corrosion damage of CTB is caused by the dissolution of hydrogen ion and sulfate ion reaction produces an expansive substance, resulting in deterioration of the strength of CTB.