Analysis on stability of surrounding rock in small coal pillar roadway with chain arm sawing

Under the condition of "three hard" coal seam in Datong mining area, with the gradual depletion of shallow coal resources, mining activities continue to go deep, and the ground stress gradually increases.Only 6 m small coal pillar is left between 8311 working face and 8312 working face in Tashan coal mine, and 2312 roadway will suffer repeated mining of the two working faces.In order to ensure the stability of surrounding rock under the influence of repeated mining of the two working faces, this premise is put forward At the same time, to ensure the coal recovery rate, the chain arm sawing developed by Tongmei group is used for mechanical roof cutting to achieve the effect of roof weakening.In order to study the stability of surrounding rock under the condition of repeated stress disturbance in two working faces, the distribution of stress and deformation of surrounding rock after roof cutting and no roof cutting is studied by means of numerical simulation and mechanical analysis.The results show that the chain arm sawing roof pressure relief can effectively cut off the stress transfer between the basic roof, reduce the peak stress of roof and floor in the retained roadway, the stress distribution is uniform, and the peak stress concentration in small coal pillar is greatly reduced, which improves the stability of surrounding rock of retained roadway; at the same time, for the small coal pillar retained roadway, the solid coal side will still be affected by the advance stress and lateral stress, forming superimposed stress concentration area and small coal pillar.In this paper, the corresponding improvement suggestions are put forward.