Advanced deep hole pre - splitting blasting of hard roof type and effect evaluation analysis

In order to verify the effect of different blasting methods on the development of rock fissures and roof caving, a study on deep-hole presplitting blasting technology for hard roof was carried out in I010203 working face of Kuanggou coal mine, theoretical analysis, numerical simulation, field test and monitoring analysis are used to analyze the influence of multi-roadway blasting type on rock burst.According to the different blasting position and sequence, the engineering types are divided, and 5 types of blasting are put forward, and 3 types are simulated and analyzed.The following conclusions are drawn: ① according to theoretical analysis, the parameters of deep hole presplitting blasting are determined. The Height of roof treatment is 40 m, the distance between holes is 10 m, and the blasting holes are arranged in a fan shape; ② analyzing and comparing the development of the fracture degree of different schemes, the fracture range of the inner fracture of coal is obviously larger than that of the Rock, and the volume of the "anti-triangle" blasting is much larger than that of the other blasting types; ③ The oblique shape further intensifies the coal stress concentration and roof activity intensity in the microseismic event gathering area in the non-blasting area, and the occurrence frequency of large energy events increases; The “one-shape” can reduce the stress concentration degree of the coal body in the agglomeration area of microseismic events in the non-blasting area, but the elimination and transfer effect of the agglomeration area is not obvious. The “inverse triangle” effectively reduces the roof activity intensity and coal stress concentration degree in the blasting area and non-blasting area, reduces the occurrence frequency of large energy events, determines the optimal advance deep hole pre-splitting blasting sequence, and reduces the risk of rock burst in the working face.