Failure Mechanism and Control of Lower Retracement Channel in Close-Distance Double-Thick Coal Seams

Figure 13

Characteristics of plastic failure of N0381 retracement channel. (a) Upper coal-pillar aspect ratio of 1. (b) Upper coal-pillar aspect ratio of 2. (c) Upper coal-pillar aspect ratio of 5.

(a)

(b)

(c)