New criterion for the spalling failure of deep rock engineering based on energy release

Abstract

Ground pressure hazards in deep rock engineering, such as rock spalling and rock burst, are big challenges and threats to personnel and equipment safety. In order to investigate the mechanism of ground pressure disasters in deep rock engineering, in-situ investigations were carried out in a deep gold mine in China. The survey results show that with the increase of the mining depth, the number and severity of ground pressure disaster events increase significantly. The investigation results of ground pressure disaster in the gold mine are analyzed by three methods. The effects of the maximum tangential stress, strain rebound and strain energy release on the failure of surrounding rock under different burial depths are obtained. The failure behaviors of surrounding rock are well explained by these methods at different mining depths. The new method considering strain energy release can well explain the phenomenon of core disking and it can accurately calculate the theoretical thickness of core disk. In addition, a theoretical calculation basis for the support design of energy absorbing bolt is provided in the paper and the support design figure is put forward by considering energy absorbing bolt. • According to in-site investigations, ground pressure hazard events increased significantly with depth. • Strain energy released by surrounding rock increases rapidly with a function of second power of mining depth. • Phenomenon of core disking is well explained, and calculation formula of rock disk thickness is provided. • The energy-absorbing materials such as energy-absorbing bolts can well absorb the released strain energy.