Constant Resistance and Yielding Support Technology for Large Deformations of Surrounding Rocks in the Minxian Tunnel

Figure 6

Failure process of the tunnel support system. (a) Tunneling face collapse. (b) Local deformation. (c) Cracking and falling off of sprayed concrete. (d) Distortion of steel frame. (e) Large-area failure of sprayed concrete. (f) Secondary lining cracking.

(a)

(b)

(c)

(d)

(e)

(f)