Experiment on Mine Ground Pressure of Stiff Coal-Pillar Entry Retaining under the Activation Condition of Hard Roof

Figure 6

Vertical displacement of the roofs above the gob. (a) Panel 1 retreating 500 mm. (b) Panel 1 retreating 650 mm. (c) Panel 1 retreating 1150 mm. (d) Panel 1 retreating 1200 mm. (e) Panel 1 retreating 1600 mm. (f) Applying additional abutment stress.

(a)

(b)

(c)

(d)

(e)

(f)