Study on Mechanical Effect and Plastic Zone Distribution of Tunnel Surrounding Rock in the Presence of Various Expansion Approaches

Figure 8

Distribution of the plastic zone of surrounding rock in 2SEE. (a) Expansion of the excavation by 1.5 m. (b) Expansion of the excavation by 3.0 m. (c) Expansion of the excavation by 4.5 m. (d) Expansion of the excavation by 6.0 m.

(a)

(b)

(c)

(d)