Rockburst Risk Analysis During High-Hard Roof Breaking in Deep Mines

Abstract

Mining operations continue to advance to greater depths to address the demand and supply of coal. However, deep mining occurs in complex and dangerous environments where mines are often subject to rockbursts induced by high-hard roof breaking (HHRB). Here, we use the #2233 working face of the Hengda coal mine as a case study to investigate the mechanism of HHRB-induced rockbursts by means of stress, electromagnetic radiation (EMR) and hydraulic support resistance. We propose an elastoplastic plate theory model to study the relationship between impact load energy and maximum roof deformation and verify the dynamic evolution of rockbursts generated by HHRB by FLAC3D numerical modeling. The results show that rockbursts are more likely to occur when the coal-rock mass under high static stress conditions is subjected to superposition of continuous dynamic stress. This is accompanied by an abrupt increase in stress, increase in hydraulic support resistance, accumulation of strain energy that is not easily dissipated and a decrease in EMR intensity. The peak dynamic stress value determines the deformation mode of the elastoplastic plate model, and the impact damage behavior of the coal-rock mass is the most apparent, whereas the maximum deformation displacement lags slightly behind the arrival time of the peak stress. The occurrence of rockbursts is accelerated by long-term and high-amplitude dynamic disturbances.