Research on stress release for gob-side roadway using roof-cutting technology with chainsaw arm
The narrow pillar mining technology is usually adopted for workface in coal mines. However, in case of overlying hard roof, a suspended triangle roof palte or a cantilever will be formed near the goaf. At this point, the coal pillars will be extruded and serious deformation for gob-side roadway will occur. In order to solve the problem, the roof-cutting technology with chainsaw arm and its equipment has been developed. In this paper, the deformation and failure characteristics of 2312 roadway near the goaf of 2311 working face in Tashan Coal Mine were firstly analyzed. So, the roof-cutting technology with chainsaw arm was applied in 2311 roadway. Next, the roof-cutting process and the load acted on the coal pillar were discussed and analyzed. Then, the numerical model was established to analyze the stress releasing effects. Moreover, the roof-cutting height and the support parameters of the roadway were optimized. The numerical analysis manifested that the roof cutting was the most effective when the roof-cutting height was 6.4 m. And after roof cutting, the vertical stresses of the coal pillars decreased by about 25.0%. Finally, the roof-cutting experiment was carried out in 2311 roadway in Tashan Coal Mine. The on-site roof-cutting depth was 6.4 m and the roof-cutting width was 42 mm. To verify the stress releasing effects, the borehole stressmeters were applied to monitor the peak advanceing stresses of narrow pillars at various depths. The measured results indicated that the peak advanceing stresses decreased by 22.8% on average and thus achieved the roof cutting and stress releasing effects.
Outstanding Innovation Scholarship for Doctoral Candidate of CUMT, Award: 2019YCBS005