Deformation Mechanism and Control Technology of Surrounding Rock in the Deep-Buried Large-Span Chamber

Figure 5

Borehole observation photos.

(a) Depth 3.0 m

(b) Depth 4.2 m

(c) Depth 5.5 m

(d) Depth 5.9 m

(e) Depth 6.4 m

(f) Depth 6.9 m

(g) Depth 7.5 m

(h) Depth 8.7 m