Abstract:

In order to avoid the problem of repeated repair of roadways in the upper mining area during

coal mining，the failure characteristics of overlying strata and the evolution characteristics of plastic zone of

roadways in the mining process of underlying coal seams were studied by means of theoretical analysis，nu⁃

merical simulation and engineering measurement. The research reveals the influence of underlying coal

seam mining on coal seam integrity and roadway stability，and determines the repair time of upper coal seam

roadway and the reasonable position of open-off cut of lower coal seam working face. During the mining peri⁃

od of the coal mine，due to the influence of the mining of the underlying coal seam working face，the plastic

damage of the upper mining rock layer is serious. Although there is no step error，there is overall subsid⁃

ence. The repair time of the upper coal seam roadway should be after the plastic zone tends to be stable. The

repair time of the upper coal seam roadway should be obvious in the plastic zone，that is，the initial stage of

severe deformation of the surrounding rock. The position of open-off cut should consider the minimum defor⁃

mation of surrounding rock and the full utilization of coal resources. The field engineering application shows

that after taking the above measures，the deformation of roadway surrounding rock meets the requirements of

coal mine production，and the multiple repairs of roadway surrounding rock deformation are avoided.

Key words:

coal seam mining, damage of formation, roadway repair, open-off cut