Abstract

This paper attempts to investigate the mechanism of induced rockbursts and inherent rockbursts of pillars in hard rock mines. By considering rockbursts as an instability (buckling) problem of structures, rockbursts are classified into induced rockbursts and inherent rockbursts according to their occurrence with or without dynamic stimulation forces. Induced rockbursts occur where the causative factor is dynamic loadings, whereas inherent rockbursts happen only when a mining structure becomes unstable under static loadings. Rigorous mathematical models are set up for these two rockbursts. For induced rockbursts, the quantitative relation between induced blasting and rockbursts is established and parametric resonance mechanism is found. For inherent rockbursts, the condition of critical static loads is obtained. Contrary to conventional methods where only rock materials or rock specimens were used to study rockbursts, this investigation attaches more attention on the structural effect on rockbursts, which tends to appeal to practising engineers.

1. INTRODUCTION

Rockbursts are sudden and violent failure of rocks, which may lead to high fatality rates, losses in production and equipment, and a detrimental influence on the recruitment of labor. In spite of the increased use of microseismic monitoring, improvements in the associated instrumentation and widespread applications of seismological data analysis techniques, the mechanism of rockbursts in underground rock engineering is still not well understood. Ortlepp said that "it is probably true that rockbursts have been the mining hazard that is the least understood and the most feared" [1]. In the 16th annual Kenneth Finlay Memorial Lecture in Australia, Suorineni (2013) claimed that rockburst is the cancer in geomechanics of contemporary deep mining.

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