Crack Initiation Characteristics of Gas-Containing Coal under Gas Pressures

Figure 6

Failure patterns of gas-containing coal changing with gas pressures (a) UC test with no gas, (b) UC test with 1.5 MPa gas pressure, (c) BD test with no gas, (d) BD test with 1.5 MPa gas pressure, (e) NSCB test with no gas, and (f) NSCB test with 1.5 MPa gas pressure.

(a)

(b)

(c)

(d)

(e)

(f)