考虑细观特征的红砂岩动态损伤与破碎的能量耗散

从细观角度深入探讨岩石动态力学特性，是理解岩石爆破破碎机理的方式之一。采用分离式霍普金森压杆对围压作用下的红砂岩试件进行动态加载，以孔隙率变化表征细观特征，基于能量耗散指标研究了红砂岩动态损伤与破碎的能量耗散。结果表明：冲击次数总体趋势是随着气压的增加逐渐减少，试件破碎前能量耗散增加，并没有明显的回弹；在第3次冲击或第4次冲击时，动态特性存在差异；在初始冲击中，孔隙度由中孔、大孔闭合到微孔，随着冲击载荷的增加，微孔孔隙度差值的峰值向后移动。

Dynamic Damage and Energy Dissipation of Broken Red Sandstone Considering Mesoscopic Characteristics

It is one of the ways to understand the mechanism of rock blasting to explore the dynamic properties of rock in mesomechanics.The dynamic loading of red sandstone under confining pressure was carried out by the split Hopkinson pressure bar,and the microscopic characteristics were characterized by porosity change.Based on the energy dissipation index,the energy dissipation of dynamic damage and fracture of red sandstone was studied.The results show that the overall trend of impact number decreases with the increase of air pressure,and the energy dissipation increases before the specimen is broken,and there is no obvious rebound.In the third or fourth shock,the dynamic characteristics are different.In the initial impact,porosity is closed from mesopores and macropores to micropores.With the increase of impact load,the peak value of micropore porosity difference moves backward.