Influence of Polypropylene Fiber-Reinforcement on the Mechanical Behavior of Gold Ore Tailings through Direct Shear Tests

To investigate techniques that focus on mining waste applied to geotechnical works, the mechanical behavior of mining waste reinforced with polymeric fibers has been studied. The present research seeks to evaluate the effects of fiber insertion in gold ore tailings using a direct shear test evaluating the peak and residual behavior. For this purpose, several conventional direct shear tests and shear planes with a polished surface in flooded conditions were conducted. To collaborate with the analysis, chemical, mineralogical, and geotechnical characterization tests were carried out, in addition to fiber tensile testing and scanning electron microscopy (SEM) in the composite. The results showed a bilinear behavior on shear strength envelopes in pure tailing, which is changed to linear behavior with the addition of fibers. For high and low stresses, an increase in the friction angle at a reinforced composite was observed. The residual behavior is suggested by the results of the shear plane test with a polished surface, in which there was also an increase in the friction angle. The volumetric behavior showed that there was a change in the pure material from being contractive to dilating when reinforced. With these results, it is possible to recommend the use of this type of reinforcement in interface areas with materials that have different stiffness—due to its adaptability to strains—or as a maintenance measure in areas affected by landslides, providing better strength characteristics to the affected area.