The induced mechanism of pillar rockbursts in deep hard rock mines

Abstract

Rockbursts remain one of the most serious and least understood problems in deep hard rock mines. This study is motivated by the pervasiveness of rockbursts all around the world. It is found that rockbursts are often induced by dynamic fluctuations, which are generated by mining excavations or other sources of vibrations, such as blasting in adjacent stopes. The objective of this paper is to investigate the induced mechanism of pillar rockbursts in deep hard rock mines. Rockbursts in underground mine pillars are considered as a dynamic instability problem of pillar structures. The quantitative relation between blasting and pillar rockbursts is established and parametric resonance mechanism of pillar rockbursts is proposed. This study shows that the damping in pillar rocks could reduce the rockburst occurrence and the minimum value of the excitation amplitude for rockbursts depends on the damping and natural frequency. Contrary to conventional methods where only rock materials or rock specimen were studied for rockbursts, this investigation attaches more focus on the structural effect on rockbursts, which has appeal for practicing engineers.