Abstract:

No.3 seam of group A of 11113working face in Pan-Bei coal mine is 4.8~6.27m, ZZP6400/18/38 roof-net supports is used in fully mechanized slicing mining, the span length of cutting hole is 9m, the height of cutting hole is 3m. Pilot tunnel and the secondary tunneling are used to ensure the safety of the construction and supporting. Also, we devise the parameter of united support of net and bolt and observe the characteristic of the stress of bolt anchor cable and single prop in both surface and internal of the cutting hole. The results show that, the stability time of roadway surrounding rock of 9 meter-cutting hole is 10 days, which is longer than the cutting hole in smaller scale, the convergence between roof and floor is 52mm, the stress of bolt and anchor cable is larger in middle than in two sides. Basing on the analysis of the observation of mine pressure, optimizing the parameters of united supports, adding dense wood crib, and have a good effect of supporting.

Key words: Large Section Open-off Cut, Slicing, thick seam, united support of net and bolt, Mineral Pressure Observation