Generally speaking, the relative displacement of the top and bottom plates exposed from the coal wall to the edge of the goaf is relatively close.
In S, sometimes for the sake of comparison, this index is often converted into the amount of ceiling for unit height and unit propulsion, that is, how many mm per meter of height per meter.
The figure below shows the close-up curve of the top and bottom of the working face, 1 is the absolute sinking curve of the top plate; 2 is the relative moving amount (sinking) curve of the top plate; 3 is the lifting curve of the bottom plate.
2. Roof sinking speed
Refers to the amount of displacement of the top and bottom plates per unit time, calculated in mm/h.
3. Deformation and damage of the pillar
4. Roof crushing
It is often expressed as a percentage of the area of â€‹â€‹the area in the area.
5. Local topping
Refers to the partial collapse of the top plate of the working face.
6. The top surface of the working face is cut along the coal wall, or it is called a large area.
It means that the working surface is cut by the top plate along the working surface, and the other is also the coal wall piece, the pillar is inserted into the bottom plate, and the bottom plate is lifted.
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