JOINT DEVICE FOR WATERPROOF SHEET

PROBLEM TO BE SOLVED: To prevent lapped parts of waterproof sheets from being not aligned or missing, when the waterproof sheets are joined by a self-travel type joint machine. SOLUTION: A new waterproof sheet 9a is joined with an existing adjacent waterproof sheet 9 by being wound with their adjacent edge parts being lapped with each other so that the waterproof sheet is cylindrically laid between the natural ground of an underground shaft excavated by a shield excavator and a segment. In this case, a self-travel type joint machine 11 which clamps the lapped parts of the waterproof segments 9, 9a so as to join them while running is allowed to travel, the simultaneously, an arm 4 on swiveling by driving a swivel ring 3 so as to support the joint machine 11 by the arm through a guide means 8. Thus, the lapped parts (a) are joined. Substantially simultaneously with the joint of the lapped parts (a), the new waterproof sheet 9a is guided so as to allow the former to approach the latter by an axial guide piece 12a of a widthwise guide 12 which swivels together with the arm, and accordingly, the width of the lapped parts a of the waterproof sheets 9, 9a are set to a predetermined width.