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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。
The improved SHPB experimental system is used to carry out rock dynamic mechanics tests. With the help of synchronous measuring device consisting of high-speed camera and dynamic strain gauge, the failure process and internal mechanism of rock subjected to impact load are studied. The results show that, in the post-peak period, a good stress balance can be maintained despite the visible fractures that have occurred in the rock samples. Rock samples were split into strips can still withstand some external stress and maintain stress balance at both ends. At the same time, further numerical simulation of particle flow shows that the process of rock failure can be described by the evolution of microcracks. Shear cracks always appear first and stop growing when the external stress drops to a certain level. However, the tensile fracture occurs when the stress on the rock specimen approaches its peak intensity, and it has a decisive effect on the ultimate failure mode.