Mechanism and Treatment of Rock Burst on the Deep Working Face Induced by Drainage in Water-Rich Areas

Abstract

Dynamic events, such as rib spalling and coal burst, occurs frequently on the coal walls and crossheadings of deep working faces in water-rich areas. This paper adopts the methods of case analysis, theoretical analysis and numerical analysis to reveal the mechanism of rock burst on deep working faces induced by drainage in water-rich areas and makes the following conclusions: (1) drainage results in the damage of rock stratum and uneven stress distribution with the stress within the damage zone decreased and the stress on the edge of damage zone increased; (2) in the mining process towards water-rich areas, the stress peaks in different positions from lowest to highest are the stress on the edge of water-rich areas, outside water-rich areas and under water-rich areas respectively; (3) drainage brings about stress concentration on the working face. It is likely to suffer from rock burst when the sum of concentrated stress and abutment pressure on the working face is larger than the critical value of rock burst occurrence. Rock burst is the most likely to take place during the mining process towards the edge of water-rich areas. On this basis, rock burst prevention measures are proposed, including optimizing the arrangement of drainage holes, slowing the mining speed, releasing large diameter pressure, increasing the initial support force of hydraulic support, selecting reasonable roadway positions and strengthening roadway support. Specifically for B Mine in the Nalinhe mining area, large-energy microseismic events can be found during the mining process towards the edge of water-rich areas. No large-energy microseismic events are monitored outside and within water-rich areas because of taking prevention measures in advance. In spite of coal burst and rib spalling, rock burst cannot be found, which ensures the face safe mining.