Effects of Ground Fracturing with Horizontal Fracture Plane on Rock Breakage Characteristics and Mine Pressure Control
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ORIGINAL PAPER
Effects of Ground Fracturing with Horizontal Fracture Plane on Rock Breakage Characteristics and Mine Pressure Control Rui Gao1,2 · Tiejun Kuang2 · Xiangbin Meng2 · Bingjie Huo3 Received: 20 May 2020 / Accepted: 26 October 2020 © Springer-Verlag GmbH Austria, part of Springer Nature 2020
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. Keywords Ground fracturing · Horizontal fracture plane · Mine-pressure control · Fracture propagation
1 Introduction Super-thick coal seams are mainly mined because of the high yield and efficiency, and the mining of super-thick coal-seam results in extensive strata movement. When multiple hard roofs exist in the overlying, in addition to a high strength and a large breaking span, the breakage of multiple hard roofs results in a strong mine pressure in the stope, which significantly affects the safe mining (Liu et al. 2019; Xu et al. 2019; Wang et al. 2019). Previous studies have revealed that in super-thick coal-seam mining (14–20 m), the migration range of the overburden can exceed 300 m (Yu et al. 2015,
* Rui Gao [email protected] * Tiejun Kuang [email protected] 1
College of Mining Engineering, Taiyuan University of Technology, Shanxi 030024, China
2
Datong Coal Mine Group Co. Ltd., Datong 037000, China
3
College of Mining Engineering, Liaoning Technical University, Fuxin 123000, China
2017), and that hard roofs within 100–150 m from the coal seam are the main factors that causing the strong mine pressure in the stope (Lan et al. 2018). Through microseismic monitoring, Ning et al. revealed that the extensive breakage of the THS released large amounts of energy, which was the main factor inducing the mine pressure (Ning et al. 2017). Li et al. revealed that the rotary mot
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