Study on mechanical characteristics of shortage backfill under dynamic impact
The backfill materials are often subject to external dynamic disturbances such as blasting and drilling when playing a supporting role,which seriously endangers the mining safety,and the length of maintenance time will also affect the mining efficiency of the mine.Therefore,the Separated Hopkinson Pressure Bar(SHPB)system is used to study the dynamic characteristics of cemented tailings backfill materials of different ages,and LS-DYNA finite ele-ment software is used to numerically simulate the stress-strain characteristics of samples under dynamic impact.The results show that under dynamic impact,the samples aged 28 d have a shorter compaction stage and a longer linear elastic stage than the samples aged 3 d,and the post-peak strength decreases significantly.The dynamic strength of the 2 samples is basically positively correlated with the strain rate.The simulation results show that there is a large stress concentration area on the side near the transmission end of the sample at the age of 3 d,and the strain is generated and extends uniformly to the incident end.The stress concentration zone and strain of the sample at 28 d of age mainly appeared in the lateral axial direction and gradually ran through the whole sample.The simulation results are consistent with the crack propagation captured by high-speed photography,and the research results can provide some theoretical reference for determining a reasonable mining time for underground mines.
cemented tailings backfilldynamic impactSHPB systemmechanical characteristicnumerical simu-lationcuring age
NETL
NSTL
万方数据
维普
