Abstract:
Aiming at the problems of serious deformation of surrounding rock, obvious stress concentration and severe periodic weighting in the return airway of the working face near the goaf side, taking the working face with an average thickness of 4.5 m and a buried depth of 380~440 m in a mine as the background, the influence of hydraulic fracturing roof cutting and pressure relief on the deformation and stress distribution of coal pillar in the section of return airway side is studied by combining numerical simulation with field industrial test. The results show that under the condition of non-fracturing, the maximum deformation of the section coal pillar is 1.6 m, and the stress concentration in the coal wall is obvious. After hydraulic fracturing, the maximum deformation of coal pillar is reduced by 0.5 m, a decrease of 50%, and the maximum stress of coal wall is reduced by 32 %. The field test further verified that after fracturing, the working resistance of the support was reduced by 16.5% on average, the microseismic events were transformed from ' high-energy low-frequency ' to ' low-energy high-frequency ', the daily average frequency was increased by 46.0%, the average energy of a single event was decreased by 10.21%, the floor heave of the return airway was reduced by about 50%, and the collapse of the end hanging roof was realized with mining. The hydraulic fracturing roof cutting pressure relief technology significantly improves the stress environment and mine pressure behavior characteristics of the surrounding rock of the return airway, and provides an effective technical way for the control of the surrounding rock of the roadway under similar conditions.