Calculation Model and Influencing Factors of Surrounding Rock Loosening Pressure for Tunnel in Fold Zone

Figure 11

The relationship between q and (t). (a) Class VI surrounding rock zone,  = 7.5°. (b) Class V surrounding rock zone,  = 12.5°. (c) Class IV surrounding rock zone,  = 23°. (d) Class III surrounding rock zone,  = 43°. (e) Class II surrounding rock zone,  = 60°. (f) Class I surrounding rock zone,  = 73°.

(a)

(b)

(c)

(d)

(e)

(f)