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

Figure 8

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

(a)

(b)

(c)

(d)