Study on Pressure Relief Effect and Rock Failure Characteristics with Different Borehole Diameters

Figure 11

Damage evolution modes of rock mass without borehole: (a) +0.1UCS; (b) +0.3UCS; (c) +0.5UCS; (d) +0.7UCS; (e) +0.9UCS; (f) UCS; (g) −0.9UCS; (h) −0.7UCS.

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)