Effects of Ground Fracturing with Horizontal Fracture Plane on Rock Breakage Characteristics and Mine Pressure Control

Abstract

Ground fracturing is a new and effective method for controlling high-level hard roofs. In underground coal-seam mining, the maximum principal stress is horizontal stress, along with the direction of hydraulic fracture propagation. In this study, the control mechanism of the horizontal fracture plane formed by ground fracturing on the strata breaking span was analyzed theoretically, and the effect of the horizontal fracture plane on the structural characteristics, stress distribution, and impact effect of the high-level thick and hard strata (hereinafter referred to as THS) were numerically investigated. To verify the results, the 8218 working face in the Tashan coal mine of the Datong mining area was selected as a case study. The fractured stratum was 20 m thick and was separated vertically from the coal seam by 110 m. After ground fracturing, the extension range of the fracture plane was 216 m in length and 30–100 m in width, covering the working face. In situ monitoring of the mine pressure revealed that the bearing strength of the supports in the working face was weakened by the ground fracturing, and that the roadway deformation was significantly reduced, indicating that ground-fracturing technology plays an important role in controlling high-level THS and improving the mining environment of the working face.