Mechanical properties, damage evolution and energy dissipation of cemented tailings backfill under impact loading

In order to explore the influence of average strain rate(ASR) on mechanical properties, damage evolution and energy dissipation of cemented tailings backfill(CTB), the dynamic test of CTB was carried out in the laboratory. This study shows that dynamic peak stress and initial crack stress of CTB increase exponentially with the increase of ASR, indicating that the characteristic stress of CTB has a significant strain rate effect. The dynamic peak strain and initial crack strain of CTB also increase exponentially with the increase of ASR, and the CTB with lower cement content is more likely to produce deformation and failure. The increase of ASR can improve the energy indexes of CTB at the peak stress point, and the increase of cement content can also improve the energy parameters of CTB. The energy storage limit of CTB increases exponentially with the increase of ASR. In addition, a dynamic statistical damage constitutive model of CTB was established considering ASR, and the accuracy and reliability were verified. There are three stages for the damage failure of CTB: rapid growth stage of damage, slow growth stage of damage and stable growth stage of damage. In addition, the high strain rate has a certain retarding effect on the development of cracks inside the CTB, thus inhibiting the rapid growth of damage value. Under impact loading, the CTB samples are mainly axial macroscopic main crack tensile failure and crushing failure. When the average strain rate is higher than the critical strain rate, the failure pattern of CTB is mainly crushing failure. When the average strain rate is basically the same, the damage degree of CTB with higher cement content is smaller.