Study on prevention and control of rock burst in affected area of overlying coal pillar based on composite weak structure

In order to realize the overall controllability of rock burst in the affected area of overlying coal pillar, the composite weak structure was proposed to dissipate the impact energy. On the basis of expounding the definition, classification and weakening degree of the composite weak structure and the mechanism of rock burst caused by overlying coal pillar, the anti-shock mechanical mechanism of the composite weak structure was analyzed. The results show that: the elastic energy index and the impact energy index decrease with the increase of the weakening degree of the composite weak structure; the composite weak structure dissipates the elasticity of the impact dangerous area by segments, which can effectively change the elastic energy release mode of coal rock; for the established residual coal pillar, the roof (coal) pre-failure measures are used to dissipate the impact energy. Field test was carried out in the coal pillar area of Tangshan Coal Mine. After the overall energy consumption measures were taken, the borehole stress value and drilling cuttings in the impact danger area were less than the critical value of rock burst, which ensured the safe production of coal pillar area.