Experimental study on mechanical properties of cemented tailings backfill under cycle dynamic loading test

During the mining process, cemented tailings backfill bodies are disturbed frequently and repeatedly by cyclic dynamical loading such as excavation and blasting. This causes damage and failure to cemented tailings backfill body and make the failure process be of accumulative feature. In addition to research on statical mechanical properties of cemented tailings backfill, it's also necessary to study on dynamic behavior and characteristics of cemented tailings backfill under dynamic loading. This study conducted a series of Split Hopkinson Pressure Bar single and cyclic dynamic loading tests on cemented tailings backfill specimens, to discover the characteristic of stress-strain, dynamic strength, deformation and failure of cemented tailings backfill specimens. It is found that, compared with the stress-strain curves under a single impact, the stress-strain curves under cyclic impact loading show more evident 1~2 low stress peaks before reaching to the dynamic peak stress. Cyclic dynamic loading was more beneficial to make the microstructures and voids inside cemented tailings backfill specimens be compacted and closed before reaching to the dynamic peak stress. This also improved the dynamic strength and bearing capacity of cemented tailings backfill specimens. The dynamic peak stress value under a cyclic loading is approximately twice of that under single loading. The final failure mode of the cemented tailings backfill specimens under cyclic dynamic loading was fracturing, and the degree of damage was less than that under single loading under similar speeds. © 2019, Editorial Board of Journal of Mining & Safety Engineering. All right reserved.