| 摘要 |
PURPOSE:To make it possible to perform easily the outbreak of a non-circular section by providing a partition wall bearing an eccentric revolution disc to the inside of an internal cylinder separately provided to the inside of a shield body so that it is capable of rotating, and laying outbreak jacks between the internal cylinder and the peripheral surface of a shield machine. CONSTITUTION:When a shield machine is driven straightly, outbreak jacks 8 and 8 are of the same length, and when a motor is driven to give rotation to both rotary discs 4 and 5, a revolution disc 3 is revolved through revolution shafts 41 and 51 while moving a position inscribed with a shield body 1. After that, the revolution of a group of cutter bits 21 is started all at once, and excavation is continued. Then, when a curve section is executed or when the outbreak is required for correcting a driving direction, one outbreak jack 8b of the outbreak jacks 8a and 8b opposite to each other is extended and, at the same time, the other outbreak jack is contracted to move an internal cylinder 7 horizontally in the direction of the outbreak. After the outbreak, the remainder 9 is excavated. |
