Research Article
Optimization for U-Shaped Steel Support in Deep Tunnels under Coupled Static-Dynamic Loading
Figure 21
The −630 m middle ramp. The red circle in the diagram shows the degree of adhesion between U-shaped steel and surrounding rock. The average spacing of U-shaped steel is 1.5 m, and the contact area ratio is approximately 1/4.
(a) |
(b) |
(c) |
(d) |