爆破回采与采空区充填是地下金属矿充填开采的核心手段，作为采空区核心承载单元的充填体势必遭受临近矿体爆破动载扰动，进而诱导基体内部结构改变影响其再承载能力和稳定性，关乎矿山安全生产。基于分离式霍普金森压杆系统(SHPB)制备了考虑冲击幅值大小的动态损伤充填体，实现了充填体爆破扰动模拟，探明了充填体在动态荷载下的细观结构响应特征，揭示了动态损伤充填体的力学行为和裂纹扩展机制，实现了动态损伤充填体的失稳超前预警。结果表明：动态损伤充填体的细观结构劣化程度随冲击幅值增加而提高，与此对应的孔隙率增加34.48%，波速减小44.48%，初始损伤程度加剧；随着冲击幅值增加，动态损伤充填体的单轴抗压强度和弹性模量呈先缓慢减小再快速减小然后再缓慢减小的3阶段变化趋势，最大减小率分别为54.15%、69.02%。同时，动态损伤充填体的应力应变曲线的压密阶段随损伤程度增加而显著延长，峰值应变提高78.35%，充填体由脆延性向延性转变；声发射特征参数与充填体的破裂行为密切相关，由于初始损伤程度差异，动态损伤充填体基体内部裂纹萌生、扩展、传播的速率、数量、尺度显著不同，体现在声发射信号上为活跃程度和疏密性随冲击幅值增加先减小再增加再减小；声发射ib值呈“波动上升—剧烈下降—大幅波动”的变化规律。随冲击幅值增加，ib值剧烈下降区增多且向峰前阶段转移。将ib值剧烈下降区判定为失稳前兆信息，动态损伤充填体在较小应力下即达到失稳临界值。增加冲击幅值对动态损伤充填体破坏模式影响不显著，但表面塌落区面积提高破坏程度明显增强。

Blasting excavation and cavity filling are the core means of filling mining in underground metal mine. As the core load-bearing unit of cavity, the backfill is inevitably subjected to the blasting dynamic load perturbation of adjacent ore body, which in turn induces some structural changes in the internal structure of matrix and affects its re-bearing capacity and stability, which is related to the safety of mine production. Therefore, in this paper, the dynamic damage filling body considering the magnitude of impact amplitude is prepared based on the split Hopkinson press bar system (SHPB), and the simulation of filling body blasting disturbance is realized. The mesoscopic structural response characteristics of the filling body under dynamic loading are investigated, the mechanical behavior and crack extension mechanism of the dynamically damaged filling body are revealed, and the instability over-warning of the dynamically damaged filling body is realized. The results show that: the degradation of meso-structure of the dynamically damaged filling body increases with the increase of impact amplitude, corresponding to the increase of porosity by 34.48%, the decrease of wave velocity by 44.48%, and the intensification of the initial damage degree. With the increased impact amplitude, the uniaxial compressive strength and elastic modulus of the dynamically damaged filling body show a three-stage trend of slow decrease, then rapid decrease and then slow decrease, with the maximum decrease rate of 54.15% and 69.02%, respectively. Meanwhile, the compaction stage of the stress-strain curve of the dynamically damaged filling body is significantly prolonged with the increase of the damage degree. The peak strain increases by 78.35%, and the filling body changes from brittle ductile to ductile. The characteristic parameters of acoustic emission (AE) are closely related to the rupture behavior of the filling body. Due to the difference in the initial damage degree, the rate, number and scale of cracks sprouting, expanding and propagating within the matrix of the dynamically damaged filling body are significantly different. The activity and sparsity of the AE signal initially decrease, then increase, and finally decrease again with the increase in impact amplitude. The AE ib value exhibits a pattern of “fluctuating increase”, “sharp decrease”, and “large fluctuation”. As the impact amplitude increases, there is an increase in the area of sharp decline in AE ib values and a shift to the pre-peak stage. The area of sharp decline in ib value is judged to be the precursor information of instability, and the dynamic damage filling body reaches the critical value of instability at a smaller stress. Increasing the impact amplitude has no significant effect on the failure mode of the dynamically damaged filling body, but the area of the surface collapse zone is increased and the degree of failure is significantly enhanced.