Failure characteristics and reinforcement support of surrounding rock in gob-side entry driving affected by residual coal pillar of upper coal seam

In order to study the failure characteristics and targeted reinforcement support measures of surrounding rock in gob-side entry driving affected by residual coal pillar of upper coal seam during the mining of contiguous seams, taking the engineering geological conditions in 051606 working face of Lingxin Coal Mine of Shenhua Ning Coal Group as background, by means of field investigation, theoretical analysis, industrial test and rock pressure observation, this paper studied the influence of residual coal pillar of upper coal seam on 051606 return airway during gob-side entry driving. The results show that when 051606 return airway is driven to the bottom of the boundary of the residual coal pillar of the upper coal seam, it is mainly affected by the shear stress, when it continues to drive to the bottom of the central axis of the residual coal pillar, it is mainly affected by the vertical stress; the main stress difference of the surrounding rock of 051606 return airway is asymmetrically distributed, and the main stress difference in the side of the coal pillar is higher than that in the solid coal side as a whole. Based on the high-strength prestressed anchor rod and single anchor cable, combined with the reinforcement ladder beam, reinforcement mesh and shed support, the strengthening control technology for the surrounding rock of the strong support roof and side wall is put forward. The field application results show that the roof-to-floor convergence and two sides convergence are both about 300 mm,and better surrounding rock control effect is obtained.