充填体材料发挥支撑作用时往往会受到爆破?钻孔等外界的动态扰动,严重危害采矿安全,同时养护时间长短也会影响矿山开采效率?采用分离式霍普金森压杆(SHPB)系统研究不同龄期尾砂胶结充填体的力学特性,同时使用LS-DYNA有限元软件对试样在动态冲击作用下的应力-应变特性进行数值模拟?研究表明:在动态冲击作用下,龄期28 d的试样较龄期3 d的试样压密阶段短,线弹性阶段长,且峰后强度下降明显,2种试样动态强度与应变率基本呈正相关关系?模拟结果表明:龄期3  d的试样在靠近透射端一侧出现较大的应力集中区,产生应变并均匀的向入射端扩展;龄期28  d的试样应力集中区与应变主要出现在侧面轴向,逐渐贯穿整个试样?模拟结果与高速摄影捕捉的裂纹扩展情况相符?研究结果能够为地下矿山确定合理的回采时间提供一定的理论参考?

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 element 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.