The deep rock mass presents a massive structure under the action of high ground stress, and the occurrence angle is complex and diverse. Under the influence of mining disturbance, the anomalously low friction phenomenon of mutual vibration and detachment occurs between the block rock masses. This phenomenon makes the rock mass originally in equilibrium reach equilibrium and stability through stress redistribution, and the stress redistribution process is easy to cause anomalously low friction rock bursts. By establishing a numerical model of the anomalously low friction effect of different angles of the blocky rock mass, using numerical simulation software to apply the force of different frequencies and amplitudes to the different angled blocks, it observes the normal force between the rock masses. It can obtain the correspondence between the disturbance parameters and the occurrence angle of the blocky rock mass. The numerical calculation shows that the disturbance frequency and amplitude remain unchanged, and the angle of occurrence of the rock mass is increased, which is more likely to cause anomalously low friction. When the disturbance amplitude is determined, when the occurrence angle exceeds a critical value, the rock block slips and loses motion. The time when the block reaches the slip state and the disturbance frequency exhibit periodic changes.

1. Introduction

Deep rock mass is characterized by high in-situ stress, high temperature, high permeability and high energy content. The physical and mechanical properties of deep rock mass are quite different from those of shallow rock mass, which is manifested in the existence of non-uniform and discontinuous block systems in deep rock mass, and can not be well solved by traditional continuum mechanics theory. Especially the dynamic phenomena such as the whole movement and interaction of rocks in deep block rock mass, which are collectively referred to by rock mechanics experts and scholars as the ultra-low friction effect in block rock mass, have become one of the hotspots of rock mechanics[1-4].

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