Research on Damage and Energy Dissipation Characteristics of Cemented Backfill under Different Loading Rates

As the destruction of the backfill caused by the mining of the ore body can be regarded as a loading process at different loading rates, a uniaxial compression test of cemented filling bodies under five loading rates was carried out in the laboratory. Based on the stress-strain curve of the filling body, according to the principle of energy dissipation and damage mechanics, the energy consumption value of the backfill at different loading rates was calcu lated and the corresponding damage evolution equation was constructed. Therefore, the internal relationship between the energy dissipation of cemented filling and the axial compression time and strain at different loading rates was studied, and the evolution process of energy damage for the cemented filling body under compression was discussed. The results show that unlike high-strength rocks, there is a critical loading rate for cemented backfill. When the loading rate exceeds the critical value, the backfill strength decreases with the increase of loading rate. The pre-peak energy consumption, post-peak energy consumption, strain energy per unit volume, and total energy consumption of the filling body have a quadratic function curve relationship with the loading rate. The total energy consumption of cemented backfill increases with the increase of axial compression time and axial strain in the form of a logistic function. However, the difference in loading rate makes the increase rate of energy consumption value, and the energy consumption of the backfill under the same axial deformation has obvious differences. The compression failure of backfill under different loading rates exhibits the same kind of damage process. The energy damage evolution process of the backfill under uniaxial loading can be divided into four stages: initial damage, stable development of damage, acceleration of damage and damage failure. © 2020, Editorial Department of Journal of Hunan University. All right reserved.