Prefabricated Urban Underground Utility Tunnels: A Case Study on Mechanical Behaviour with Strain Monitoring and Numerical Simulation

Figure 9

Main stress variation curve of concrete on the midline of the side wall. (a) First principal stress on the outer surface. (b) Third principal stress on the outer surface. (c) First principal stress on the inner surface. (d) Third principal stress on the inner surface.

(a)

(b)

(c)

(d)