Study on Energy Release of Surrounding Rock under the Multiple Unloading Disturbance during Tunnel Excavation

Figure 10

Damage distributions of surrounding rock caused by transient unloading of in situ stress. Both shear-n and shear-p in the figure indicate that the rock mass is damaged. (a) ms1. (b) ms3. (c) ms5. (d) ms7. (e) ms9. (f) ms11.

(a)

(b)

(c)

(d)

(e)

(f)