| 摘要 |
The purpose of the present invention is to form a passageway of substantially uniform height for which costs are reduced and on-site labor time is reduced. The following are provided: a head separation step for removing a head (13); a connection unit fitting step for attaching to an end tunnel (9) a connection unit (11) which is pre-made and to the bottom of which a chain sprocket (33) is attached; a passageway member attachment step in which one end of a passageway member is fixed and attached to a base tunnel (7) and the other end is attached by winding the chain sprocket (33) therearound; a head fitting step for attaching the head (13) to the connection unit (11); and a connection passageway unit attachment step for attaching a connection step (73) to the head (13). In the connection unit fitting step, the upper end position of the chain sprocket (33) is made to be a position such that the upper surface of the passageway member around which the chain sprocket (33) is wound matches the upper surface of an inner passageway (25). |
