Numerical analysis of stress field distribution and blasting-induced rockburst at Hongtoushan Copper Mine

Abstract

Hongtoushan Copper Mine is the deepest underground metal mine in China. With the mining depth increasing, mining in high stress condition is the major factor leading to rockburst hazards, and that has been a dominant problem in this mine. Rockbursts induced by high-stress mining often cause production losses, damage to equipment, collapse of roadways and stopes, even loss of life. In this paper, in order to analyse the mechanics and dynamics of rockburst during mining process, a FLAC2D (3.0) numerical model was set up and analysed the stress field distribution of cut and fill method during the total stoping process. Numerical modelling results show that the high stress concentration area appears when the stoping height is 32–48 m. The main failure modes are spalling and bursting in the sidewall, which is accordance with field investigations. In order to analyse the mechanics of bursting induced by blasting energy, different blasting energies were considered and analysed by using FLAC2D dynamic analysing method. Numerical results show a blasting energy can induce the rockburst when the pillar/sidewall is in a high stress condition. Meanwhile, destress blasting was applied to control the high stress distribution and reduce the rockburst hazards, which is valuable for providing the knowledge used to improve the stability of mine excavations.