Easily-cuttable tunnel segment structure

A tunnel segment structure for a tunnel comprising:

• a plurality of tunnel segment pieces connected to each other in the longitudinal direction of the tunnel, said plurality of tunnel segment pieces having an area to be cut extending over said plurality of tunnel segment pieces;
• each of said plurality of tunnel segment pieces having said area to be cut being formed of concrete;
• at least in said area to be cut in each of said plurality of tunnel segment pieces, a plurality of curved fiber-reinforced plastic rod chord members are disposed in the said concrete in the circumferential direction of the tunnel and a plurality of fiber-reinforced plastic stirrups are disposed in said concrete in the longitudinal direction of the tunnel;
• fiber-reinforced plastic joins connecting in the longitudinal direction of the tunnel adjacent tunnel segment pieces of said plurality of tunnel segment pieces having said area to be cut;
• a steel plate structure embedded in said concrete of said plurality of tunnel segment pieces having said area to be cut at an outer perimeter of said area to be cut, whereby said steel plate structure surrounds said area to be cut and is located at a boundary between said area to be cut and a non-cut area;
• said steel plate structure embedded in said concrete at an inner circumferential surface of each of said plurality of tunnel segment pieces having said area to be cut, with said steel plate structure projected and exposed above said inner circumferential surface.