The Research on Reasonable Support Capacity of Workface in Coal Seam with Thin Upper Cover

摘要

The showing of ground pressure is severe in workface of coal seam with thin upper cover, due to the thin upper rock seam and the action of upper incompact cover. Generally, the thin cover coal seam with 90m upper cover can be defined as Coal seam with thin cover. The result of simulation experiment for workface with thin cover and 5m mining height shows that under overburden pressure, the step subsidence is obvious, and balanced structure is still formed in surrounding rock, under overburden pressure. But the shape and form of balanced structure are different from the balanced structure formed upper coal seam with normal buried depth. There appears step or dislocation between the upper rock seam in workface and the balanced structure in the mined-out area, and the quantity of dislocation is 2m. But no step subsidence appears in the simulation for the workface with thin cover and 3m mining height. So the mining height is the key for the step subsidence. This paper gives out the movement model of surrounding rock upper the workface in thin cover coal seam and chooses 1 MPa as the support capacity for the first workface of Gaotouyao Colliery based on calculation.