Prestressing introduction manner null of segment, and shield tunnel covering works body for shield tunnel covering works body

摘要

PROBLEM TO BE SOLVED: To provide a segment for a shield tunnel covering in which a prestress is introduced in the circumferential direction, simplify the structure in the neighborhood of the tightening or fixing end of a PC steel material, and establish a uniform prestress introduction in the circumferential direction. SOLUTION: A duct 4 to admit insertion of PC steel material is furnished in the circumferential direction of a segment 1 made of concrete and communicate with an anchor body 5 embedded and fixed in the segment. The anchor body 5 is made by casting in such a structure that two cylindrical members are joined together to generate X-shape, and a notch 6 is provided at the inside of the segment 1 so that the anchoring end is exposed. The PC steel material inserted through the duct 4 goes round inside the covering in one turn, wherein the two ends are threaded through two penetrative holes provided in the anchor body and drawn out to inside the covering, and is fixed by a wedge after a tension force is introduced.