Numerical Modeling on Hydraulic Fracturing in Coal-Rock Mass for Enhancing Gas Drainage

Figure 10

Distribution diagram of cracks evolution during hydraulic fracturing process (m = 20). (a) Step 12_99. (b) Step 14_55. (c) Step 15.5_28. (d) Step 18.5_9.

(a)

(b)

(c)

(d)