Fracturing pressure relief roadway protection technology of thin spacing dynamic pressure roadway under disturbance of residual coal pillar

CHEN Xueya; ZHANG Ningbo; LIU Liming; CHEN Baobao; FU Shixiong

doi:10.11799/ce202501007

Abstract：In response to the problem of large deformation caused by high stress bearing capacity of dynamic pressure roadways under the conditions of the residual coal pillars disturbance and thin spacing rock,taking 10102 transportation roadway of Huangjiagou Coal Mine as the engineering background,a stress transferring model of the floor under the action of residual coal pillars and multi-state thin interlayer rock layers was established.The stress transfer and coal sliding characteristics under different fracturing angles in the target roadways were elaborated,and fracturing parameters based on stress source and transmission path control were determined.The pressure relief of fracturing roof was carried out on site.The results showed that,the influence of residual coal pillars on the floor is mainly vertical stress,and the pressurization forms the 8#+9#coal seam floor loading area under the action of degradation bearing capacity of fractured rock mass and the blocking transmission effect of broken expanding rock mass in goaf.It also generates additional stress on the surrounding rock of 10 coal seam mining roadway,determining the sensitivity angle of the stress concentration boundary line.The fracturing weakening of interlayer rock improves the stress environment of the coal pillar below the roof cutting line and reduces the load-bearing of the residual coal pillar and the transmission degree of mining-induced stress to 10#coal pillar,obtaining the equivalent fracturing weakening width with 7.5 m.The fracturing with 45° cutting angle corresponds to a horizontal fracturing distance of 12.5 m in the interlayer rock,and the vertical stress,deformation,and coal pillar sliding degree of the target roadway surrounding rock reach the minimum.After fracturing with 45° on site,the fracture network was developed and penetrated,achieving pre-splitting and roof cutting.The roof,floor and two roadsides deformation decreased by 60.1％and 65.5％,respectively,compared to conventional conditions,improving the the surrounding rock stability and ensuring high production and efficiency of the working face.