THEORETICAL AND EXPERIMENTAL STUDY OF HARD ROCK SPALLING FRACTURE UNDER IMPACT DYNAMIC LOADING
LI Xibing1，2，TAO Ming1，2，GONG Fengqiang1，2，YIN Zhiqiang1，2，DU Kun1，2
(1. School of Resources and Safety Engineering，Central South University，Changsha，Hunan 410083，China；
2. Hunan Key Laboratory of Resources Exploitation and Hazard Control for Deep Metal Mines，Central South University，
Changsha，Hunan 410083，China)
Abstract：Through a theoretical analysis of the spalling characteristics of rocks under the impact loading of the half-sine wave incident，the location and thickness of rock spalling fracture are obtained. In the laboratory，the improved Split Hopkinson pressure bar device which produces the incident half-sine wave is applied to measure the spall characteristics of the granite specimens. The complete experimental process is recorded by a high-speed camera. Test results show that the rock specimens under the impact loading of the half-sine incident wave only produce one spalling layer initially，which is completely in accord with the theoretical analysis；and the rock specimens produce several spalling fractures with time. The analyses of both pictures from the high-speed camera and waveform recorded by dynamic strain gauges indicate that the reason of following small spalling fractures is the damages of rock specimens caused by the initial loading. For a damaged rock specimen，a very weak residual reflected wave spreading along the specimen will make it produce small spalling fractures. Hence, the investigation on the spalling characteristics of rock or other brittle materials should not only consider the dynamic tensile fracture caused by the interaction of incident and reflected waves，but also should take the influence of material damage into account. The research methodology of this paper based on the waveform theoretical analysis of the spalling characteristics and the experimental technique with high-speed camera will be helpful for the area of understanding the rock spalling process or other relevant characteristics.
李夕兵1，2，陶 明1，2，宫凤强1，2，殷志强1，2，杜 坤1，2. 冲击载荷作用下硬岩层裂破坏的理论和试验研究[J]. 岩石力学与工程学报, 2011, 30(6): 1081-1088.
(1. School of Resources and Safety Engineering，Central South University，Changsha，Hunan 410083，China；. THEORETICAL AND EXPERIMENTAL STUDY OF HARD ROCK SPALLING FRACTURE UNDER IMPACT DYNAMIC LOADING. , 2011, 30(6): 1081-1088.
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2011, Vol. 30 
