Analysis of the spalling process of rock mass around a deep underground ramp based on numerical modeling and in-situ observation

Abstract

A comprehensive analysis method based on numerical simulation, displacement monitoring and digital borehole photography was proposed and employed to analyze the spalling characteristics and damage range. A continuous–discontinuous numerical model was set up, and which was calibrated based on field displacement monitoring data from Hongtoushan copper mine, and a developed continuous-discontinuous element method (CDEM) coupling the finite element method and the discrete element method was used to investigate the spalling initiation and propagation in the deep underground ramp under periodic stoping conditions, which was verified by the digital borehole photography. The results showed the initiation, propagation of ramp spalling associated with continuous periodic mining-induced stress, and parallels to the vertical stress direction. Severely spalling failure occurs at the left wall of the ramp, and the spalling depth is about 0.6 m. The spalling strain analysis also indicates that large-scale spalling failure occurs in the left wall, and which was verified by the digital borehole photography observation. The numerical simulation and field observation have good consistency. The comprehensive analysis method provide more realistic results, which helps to understand spalling failure mechanisms in deep hard rock mining and provide references for rock support.