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Coal Engineering ›› 2023, Vol. 55 ›› Issue (8): 119-123.doi: 10.11799/ce202308022

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Experimental Study on Influence of Gas Drainage Drilling on Explosive Fracture Propagation

  

  • Received:2022-03-23 Revised:2022-07-25 Online:2023-08-20 Published:2025-04-08

Abstract:

In order to effectively improve the permeability of high-gas and low-permeability coal seam and the effect of gas drainage, the influence of gas drainage borehole on the development law of coal blasting fracture was studied by combining theoretical analysis, similar simulation test and numerical simulation. The research shows that the incident compressive stress wave is reflected in the nearby coal body through the extraction hole, causing the coal body to be subjected to both tangential tensile stress and radial tensile stress. When the tangential tensile stress is greater than the dynamic tensile strength of coal body, the coal body is pulled to form radial cracks. When the radial tensile stress intensity is greater than the dynamic tensile strength of coal, the coal fracture produces circumferential cracks. The main cracks around the blasting hole expand to the side of the extraction hole, and form a cross fracture network with the cracks around the extraction hole. Through the field application of a working face in Huainan Coal Mine, the gas extraction concentration is 3 ~ 4 times and 2 ~ 3 times before blasting when the extraction hole is 3 m and 4 m away from the blasting hole. The results show that the influence of gas drainage borehole on the expansion and development of explosive fractures can effectively improve the permeability of coal seam and the effect of gas drainage.

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