Mechanical properties and energy distribution evolution characteristics of fiber-reinforced cemented sulfur tailings backfill

The uniaxial compression test of fiber reinforced sulfur tailings cemented backfill was carried out in the laboratory. The influence of fiber content on the mechanical characteristics of backfill was studied, and the energy distribution evolution characteristics and damage evolution process of cemented backfill with fiber reinforced sulfur tailings before peak stress were revealed. The results show that the stress-strain curve of the backfill with polypropylene fiber does not decrease rapidly after the load exceeds the stress peak, indicating that the fiber addition improves the ability of the backfill to resist deformation and failure. The axial stress and axial strain of backfill firstly increase and then decrease with the increase of fiber content, and the effect of polypropylene fiber on increasing residual stress is obviously higher than that on increasing peak stress. The total strain energy, elastic strain energy and dissipative energy of cemented filling with sulfur tailings reinforced by fiber increase first and then decrease at the peak stress, and reach the maximum value when the fiber content is 0.6%. In addition, when the fiber content is 0−0.6%, the total strain energy increases with the increase of fiber content in a linear function, while the elastic strain energy and strain energy per unit volume increase with the increase of fiber content in an exponential function. The growth rate of the damage value of the backfill with fiber is significantly slower than that of the backfill without fiber, and the damage and failure process of the backfill before the peak stress mainly goes through three stages. © 2022 Central South University of Technology. All rights reserved.