Study on Stability Control of Retained Gob-Side Entry by Blasting Fracturing Roof Technology in Thick Immediate Roof

Figure 11

The plastic zone distribution under different fracturing heights and angles. (a) Case 1 (fracturing main roof with 60°). (b) Case 2 (fracturing main roof with 75°). (c) Case 3 (fracturing main roof with 90°). (d) Case 4 (fracturing immediate roof with 90°). (e) Case 5 (fracturing immediate roof with 75°). (f) Case 6 (fracturing immediate roof with 90°). (g) Case 7 (nonfracturing roof).

(a)

(b)

(c)

(d)

(e)

(f)

(g)