Research on energy release in coal rock fragmentation process under impact load
LIU Xiaohui1，2，XUE Yang2，ZHENG Yu2，GUI Xin2
(1. Key Laboratory of Fluid and Power Machinery of Ministry of Education，Xihua University，Chengdu，Sichuan 610039，China；2. School of Energy and Power Engineering，Xihua University，Chengdu，Sichuan 610039，China)
Abstract：In order to explore the energy release characteristics of rock fragmentation，impact compression tests with different strain rates and initial stress levels are carried out on coals by the Hopkinson pressure bar. In this paper，the elastic energy is calculated based on the dissipated energy of SHPB tests. The energy release characteristics are discussed under different confining pressures and strain rates. The effect of energy release on rock fragmentation is further investigated. The results show that：based on the energy evolution process，the dynamic stress-strain curve of coals can be divided into 5 stages under impact load. The obvious strain rate effect of coal was proved. The energy release lag effect was discovered in the process of rock failure. The elastic energy is released after the peak stress. As the strain rate increases，it is found that the elastic energy storage limit increases with quadratic polynomial and the elastic energy release stress increases linearly. The normalized value of release stress is found to increase linearly under uniaxial condition and decrease linearly under triaxial condition. With the increase of confining pressure，the strain rate dependence of release stress is weakened. The energy index W is put forward based on the release degree of elastic property. The effect of rock fragmentation can be reflected by W. The inverse relationship between W and fragmentation degree of coal rock was found. A new reference means for improving rock-breaking effect and preventing dynamic disaster are provided through W.
刘晓辉1，2，薛 洋2，郑 钰2，桂 欣2. 冲击荷载下煤岩破碎过程能量释放研究[J]. 岩石力学与工程学报, 2021, 40(S2): 3201-3211.
LIU Xiaohui1，2，XUE Yang2，ZHENG Yu2，GUI Xin2. Research on energy release in coal rock fragmentation process under impact load. , 2021, 40(S2): 3201-3211.
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2021, Vol. 40 
