Study on the mechanism and prevention and controlof roadway impact in strong impact coal seam under the influence of mining

In view of the actual problem of frequent occurrence of rock burst in coal seam roadway, numerical simulation, field measurement, monitoring analysis and other methods were used to study the mechanism of rock burst in coal seam roadway with strong impact under the influence of mining, and the prevention and control methods were proposed. The results show that in the mining of extra-thick coal seam under hard roof, the influence range of advance stress in single goaf is about 180 m, and the influence range of superimposed stress in double goaf is about 240 m, and the influence degree of superimposed stress in double goaf is significantly greater than that in single goaf. During the final mining of the working face, affected by the superposition of the two goafs, the microseismic energy and frequency in the main coal seam roadway area increased exponentially, especially when the distance from the working face to the main coal seam roadway was less than 180 m, the increase level increased rapidly, and the total energy released every 15 days was 43 times that of the previous 15 days. The cantilever and roadway intersection formed by the hard roof slab overlying the adjacent goaf are the source of the static load in the main roadway area of the coal seam, while the disturbance effect produced during mining and the sudden collapse of the hard roof are the source of the dynamic load in the main roadway area of the coal seam. The static and dynamic loads caused by the above factors and the "mutual feedback" effect between them are the obvious reasons for the occurrence of rock burst in the main roadway area of coal seam under the influence of mining. The instability of the basic mechanism of the complex mechanical system in the surrounding rock of the main roadway under the influence of mining and its sensitivity to the disturbance of the surrounding environment are the potential reasons for its impact appearance. Therefore, a targeted collaborative prevention and control should be carried out by combining the methods of optimizing the width of the protective coal pillar, the deep-hole pre-splitting blasting of the roof and coal seam danger relief. The field practice shows that the effect of cooperative prevention and control is good, especially the optimization of the width of protective coal pillar to make it larger than the overlapping influence range of double goafs, which can greatly improve the effect of prevention and control.