Dynamic behavior of rock during its post failure stage in SHPB tests

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• 作者：Zi-long ZHOU^a ; ^{zlzhou@csu.edu.cn} ; Yuan ZHAO^a ; Yi-hui JIANG^b ; Yang ZOU^c ; Xin CAI^a ; Di-yuan LI^a
• 关键词：rock dynamics ; post failure ; stress equilibrium ; crack evolution ; particle flow code
• 刊名：Transactions of Nonferrous Metals Society of China
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：27
• 期：1
• 页码：184-196
• 全文大小：5597 K
• 卷排序：27

文摘

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.