STRUCTURE OF SEGMENT

PROBLEM TO BE SOLVED: To provide the structure of a segment, in which long-sized segments can be assembled without generating the unbalance of the reaction of a jack in a shield machine in normal length. SOLUTION: A tunnel is constructed by combining two segments L having long sides and two segments S having short sides in the structure of the segments. The length of the segment S having a short side assembled first is constituted in the same size as the length of the outsides of the short sides of a tunnel skeleton. The length of the segment L having the long side assembled next is configured in short size shorter than the length of the outsides of the long sides of the tunnel skeleton by the thickness of the segments S having short sides. The length of the segment L having the long side built up next is organized in short size shorter than the length of the outsides of the long sides of the tunnel skeleton by the thickness of one segment having the short side. The length of the segment S having the short side built up by insertion between both segments L having the long sides lastly is constructed in short size shorter than the length of the outsides of the short sides of the tunnel skeleton by the sum of the thickness of both segments L having the long sides.