Surrounding rock control technology of roof cutting for pressure relief in small coal pillar roadway under secondary mining

In order to solve the problems of severe rock pressure and large deformation of surrounding rock in the roadway with small coal pillar under the influence of multiple mining,a technology combined cutting roof for pressure relief with top and side cable reinforcement was proposed. Taking the 10115 headentry of Jiajiagou Coal Mine as the research object, the relationship between the location and height of cutting roof for pressure relief and the vertical stress distribution of the surrounding rock of the roadway was analyzed,and the key parameters of cutting roof for pressure relief were given. The strata behaviors of the roadway with small coal pillar was studied under the influence of two mining movements after cutting roof for pressure relief. The results show that the peak stress of the coal pillar decreases exponentially with the increase of the roof cutting depth. In the adjacent working face mining process of 10115 headentry, also called the primary mining, roadway surrounding rock deformation changes from no deformation,slow deformation,rapid deformation to stability in turn. In the own working face mining process of 10115 headentry, called the second mining, the roadway deformation changes from slow deformation to significant deformation. The deformation of the roadway surrounding rock in the secondary mining is much larger than that in the primary mining,about from 3. 0 to 7. 5 times.