ENTRANCE DEVICE FOR ARRIVAL OF SHIELD

摘要

PROBLEM TO BE SOLVED: To surely prevent a ring-shaped expandable sealing member from being damaged by external factors from excavated soil etc. SOLUTION: A cylindrical entrance chamber 17 is provided inside a vertical shaft 3 which is constructed in the position of arrival of a shield machine 1; the ring-shaped sealing member 19, which can be switched between in an expanded seal-operating state and a contracted standby state, and a protective cylindrical body 21, which is provided inside the sealing member 19 in the standby state, are provided in the entrance chamber 17; the cylindrical body 21 is exposed by being slid up to a position to go out of the area of the sealing member 19 by the advance of the shield machine 1 into the entrance chamber 17; and the exposed sealing member 19 is expanded so as to be brought into elastic contact with the peripheral wall surface of the shield machine 1. COPYRIGHT: (C)2004,JPO