Field investigation of roof hydraulic fracturing technology for protecting main roadway disturbed by mining stress in 13521 working face of Gubei Coal Mine

There are several key thick and hard rock strata in the roof of No.1 coal seam in Gubei Coal Mine.The thick and hard rock strata transmit the far field mining stress, which makes it difficult to control the surrounding rock of the main roadway in the mining area.Therefore, the technical test of roof hydraulic fracturing stress transfer to protect the main roadway in the mining area is carried out at 13521 working face of Gubei Coal Mine.The test results show that the water pressure monitoring data well reflects the expansion and development process of hydraulic fractures in the target rock stratum.The typical water pressure change process can be divided into six stages.The phenomenon of water flowing from fracturing hole, adjacent hole and surrounding rock during fracturing reflects the fracturing effect, and the field construction phenomenon reflects that the single hole fracture expansion range is at least 20 m.The propagation path of mining stress to the main roadway in the mining area is effectively cut off through the combined fracturing of high and low hard rock strata of the roof.The deformation of main roadway in the mining area near working face is less than 5 cm, and the deformation of the main roadway in the mining area is effectively controlled.The test can provide experience reference for mines with similar problems.