中文摘要：

运用改进的SHPB实验系统开展岩石动态力学试验,借助高速摄影仪和动态应变仪组成的同步测量装置研究岩石在冲击荷载下的破坏过程和内在机制。结果表明：在峰后阶段,尽管岩样已经产生了可见的裂隙但仍能保持很好的应力平衡状态。岩样被劈裂成条状后依然能承受一定的外应力并保持两端的应力平衡。同时,进一步的颗粒流数值模拟显示,岩石的破坏过程可以用微观破裂的演化来描述。剪切裂隙总是最先出现并在外部应力下降到一定水平时停止增长。然而,拉伸裂隙在岩样所受应力接近其强度峰值时出现,并对最终的破坏形态起决定性的影响。

英文摘要：

In order to investigate the micro-process and inner mechanism of rock failure under impact loading, the laboratory tests were carried out on an improved split Hopkinson pressure bar （SHPB） system with synchronized measurement devices including a high-speed camera and a dynamic strain meter. The experimental results show that the specimens were in the state of good stress equilibrium during the post failure stage even when visible cracks were forming in the specimens. Rock specimens broke into strips but still could bear the external stress and keep force balance. Meanwhile, numerical tests with particle flow code （PFC） revealed that the failure process of rocks can be described by the evolution of micro-fractures. Shear cracks emerged firstly and stopped developing when the external stress was not high enough. Tensile cracks, however, emerged when the rock specimen reached its peak strength and played an important role in controlling the ultimate failure during the post failure stage.