Shallow-depth tunnel with large cross section
Shallowly embedded big fracture section tunnel
Small Cross Section Tunnel
sudden change of tunnel section
Super Large Section Tunnel
tapering section of the wind tunnel
the wide section tunnel kiln
transition section at tunnel opening
Transition Section between Subgrade and Tunnel
tunnel boring on curved section
Tunnel Entrance Section
tunnel of large section
Tunnel Portal in Unfavourable Geological Section