CONSTRUCTION METHOD FOR TUNNEL GIRDER

PURPOSE: To expand the degree of design freedom for the mechanical strength of a girder section and the joint thereof by loosely tightening a screw member for jointing the girder section. laying a plurality of segments at forward positions and, then, strongly tightening the screw member. CONSTITUTION: Segment 10 and so forth integrated with girders are formed out of lining segment sections 12 and 12, and girder sections 14 and 14 for bearing a load acting thereon, and are arranged in sequence along a tunnel axial direction, according to the development of tunnel excavation. Then, the segment sections 12 of adjacent segments 10 are connected to each other with a plurality of the first screw members, and the girder sections 14 are jointed to each other with a plurality of joint plates 30 thereon, and a plurality of the second screw members. In this assembly process, the first screw members are tightened and the second screw member tightened loosely. Then, after the segments 10 are arranged at forward positions, the second screw members are strongly tightened. As a result, the consideration of the effect of reaction due to thrust is not required at the time of designing the girders, thereby expanding the degree of design freedom.