Study on early mechanical properties and damage constitutive model of tailing-cemented backfill with different fibers

In order to improve the stability of tailing-cemented backfill of a gold mine and to ensure the backfill effect of the goaf of the mine, the early mechanical properties and damage characteristics of tailing-cemented backfills with different fibers(polyacrylonitrile fibers, glass fibers, polyacrylonitrile fibers and glass fibers mixed fibers) were studied, and adamage constitutive model of the tailing-cemented backfill with different fibers was obtained by uniaxial compression test. The test results show thatthe uniaxial compressive strength of the tailing-cemented backfill with glass fibers is the largest, followed by mixed figers, polyacrylonitrile fibers and fibreless. The fibers have obvious interference and retarding effect on the crack propagation, making the cracks more and smaller, and greatly enhance the toughness of the cemented tailings backfill. The crack blocking effect of mixed fibers is significantly better than that of single fibers. The tailingcemented backfill with fibers does not completely lose its load-bearing capacity after the peak, and continues to carry part of the compressive-shear stresses due to its high toughness. A theoretical damage constitutive model of tailing-cemented tailings backfills with different fibers was built, and the model curve was obtained through correcting the damage variables by six different damage parameters. Finally, the theoretical model was verified through experiments. It is revealed that the stress-strain curves from the model and the experiments are in good agreement, showing that the established theoretical model has certain reference value for the analysis and evaluation of the mechanical properties of tailing-cemented backfills with different fibers. © 2022, Science Press. All right reserved.