Research on mining stress distribution law of coal body during open-off cut butt-joining stage of knife handle working face

Taking the 23304 knife handle working face of Yungaishan No.2 Coal Mine as the engineering background, the pressure distribution and ground pressure law of the coal around the joint face during the transition from short working face to long working face are studied when the fracture types of the main roof of the working face directly affects the knife handle working face. Theoretical analysis combined with 3DEC numerical simulation was used to analyze the different fracture types and overlying rock structural characteristics of the main roof at the docking stage between No.1 open-off cut and No.2 open-off cut of Yungaishan No.2 Coal Mine, revealing the influence law of different rock beam properties on the range of internal stress field. The results show that the degree of influence of lateral key block B fracture on the coal body is from small to large: the side of the mining area, in front of the coal wall, and directly above the coal wall, the location of the lateral basic top fracture is 6.21 m deep into the coal body, and the internal stress field range is about 12.91-14.43 m. The elastic modulus of the coal body shows a negative correlation and the most significant influence on the internal stress field range.