Classification control technology of unequal thickness roof of close distance coal seam roadway

Aiming at the difficult problem of surrounding rock control in roadways with unequal-thickness roofs in closely spaced coal seams, taking the mining roadway of the No. 17 coal seam in Lutian Coal Mine as the engineering background, the mechanical characteristics of the surrounding rock of the roadway in the lower closely spaced coal seam were studied through on-site measurement. The research results show that the roof thickness of the No. 17 coal seam is uneven. The strength of the roof with a thickness of 2～3 meters shows the characteristic of "soft in the lower middle part and hard in the upper part", and its structure is loose. The roof with a thickness of more than 3 meters has a complete structure and higher strength. The sandy mudstone of the immediate roof has strong water-induced deterioration characteristics. Based on the test results, the roof stability classification was carried out. Combining the development of geological structures, the relationship between the upper and lower strata, etc., the roof was divided into three categories: stable, relatively unstable, and unstable. A differentiated support design based on different roof stability classifications was proposed, and the support effect was verified through mine pressure monitoring. The research results provide technical support for the safe and efficient control of the roof of roadways in closely spaced coal seams.