冲击加载下养护龄期对掺膨润土充填体力学破坏特征研究

深部开采中爆破、地震波等冲击对不同养护期的胶结充填体稳定性造成破坏,威胁采场安全.为此采用霍普金森杆试验系统对充填体试样进行单次冲击试验,分析爆破荷载下不同龄期掺膨润土全尾砂胶结充填体的动力学特性.结果表明:动态冲击曲线存在多个波峰,养护早期(3、7 d)表现为动态强度硬化(峰值应变0.005左右),后期(14、28 ...

Influence of curing age on mechanical failure characteristics of bentonite backfill under impact loading

In deep mining, the impact of blasting and seismic wave will damage the stability of cemented backfill in different maintenance periods and threaten the safety of stope. In order to analyze the dynamic characteristics of cemented backfill with bentonite at different ages under blasting load, the single impact test of backfill samples was carried out by using Hopkinson bar test system. The results show that there are multiple peaks in the dynamic impact curve, the dynamic strength hardening (peak strain about 0.005) in the early stage (3d, 7d) and the dynamic strength softening (peak strain about 0.002) in the later stage (14d, 28d); DIF is positively correlated with bentonite content and negatively correlated with age; When the curing age is 3-14 days, the dynamic compressive strength, absorbed energy and absorbed energy per unit volume decrease first and then increase with the increase of bentonite content (10% is the critical point). When the curing age is 28 days, the two are positively correlated. The extension of curing age can improve the energy absorption capacity and enhance the impact resistance of backfill; The correlation between the two indexes is higher in the early curing stage and higher in the later curing stage.