| 摘要 |
PROBLEM TO BE SOLVED: To obtain a highly reliable underground structure by an open shield method, in which a concrete box body prevents chipping and cracking of an outer peripheral corner even when exposed to an extrusion load from a propulsion jack, and enables water cut-off between the concrete box bodies readily and completely even when a cross-section is large.SOLUTION: A concrete box body is of a roughly square cylindrical form comprising a left side plate 8a, a right side plate 8b, and a top floor plate and a bottom floor plate, and has a connecting part 16 formed on an end and a connected part 17 formed on the other end. The connecting part 16 is a roughly square cylindrical male member. The connected part 17 is of a roughly square cylindrical form having an inner periphery that is longer than an outer periphery of the connecting part, and is a female member that may be fitted on an outer peripheral surface of the connecting part 16. A steel press bar 10 is engaged and disengaged on the female member of the connected part 17 at the edge part of the concrete box body lowered into the tail part of the shield machine.SELECTED DRAWING: Figure 2 |
