Failure analysis and control of retained roadway at working face under protection coal pillar of the faults

Abstract

Aiming at the severe damage at retained roadway of coal seam 4-2 working face in Buertai coal mine, which is under 2-2 coal seam protection coal pillar of the faults, the failure characteristics and disaster mechanism of retained roadway under the protection coal pillar of faults were studied by means of field measurement, theoretical analysis and numerical simulation.Researches show that:① The deformation and failure of retained roadway are obviously regional, which is obviously more severe under the protection coal pillars of the faults;② Multiple mining operations result in different superposition and unloading of vertical and horizontal stresses, the maximum vertical stress being 1.8 times of that under the protection coal pillar of the faults.③ After repeated mining, plastic zone of retained roadway under the coal pillar is 2~3 m, while it is about 1~1.5 m under the goaf.The measures of hydraulic fracturing and anchor cables support are put forward, which has been proved effective

Keywords

• protection coal pillar
• retained roadway
• deformation and failure
• distribution of stress
• reinforcing support
• hydrofracturing