| 摘要 |
PURPOSE:To make it possible to obtain stabilized excavation reaction force while preventing a bedrock from fall of rocks or collapse without damaging a tunnel wall even if the bedrock is constituted of cracked rocks or poor rocks having a fractured zone. CONSTITUTION:In the case cracked rocks or poor rocks having a fractured zone are excavated, the lower half of a section in a tunnel backward of an excavator main body 1 is temporarily backfilled with excavated muck 20, pressure is applied to the backfilled excavated muck 20 from the direction of the axis and above, and thrust reaction force is generated with the two way pressurized force and self-weight of the excavated muck 20. The excavation reaction force of the excavator main body 1 is acted on the backfilled excavated muck 20, the excavator main body 1 is driven to excavate, driving reaction force of the excavator main body 1 is acted on the tunnel wall 10 through broad and frictional contact in the case the ground of good quality is excavated, and the re-shoring of the driving reaction force is made to the tunnel wall 10 to excavate. |
