Research Article

Rotational Failure Mechanism for Face Stability of Circular Shield Tunnels in Frictional Soils

Figure 14

Stability charts of the critical pressure supported on the tunnel face under the pore water pressure ru = 0.5. (a) φ = 40°. (b) φ = 30°. (c) φ = 20°. (d) φ = 10°.
(a)
(b)
(c)
(d)