| 摘要 |
<p>PURPOSE: To enlarge a tunnel while using the tunnel by providing a protection shield within the original tunnel in the section of the tunnel involved in the enlarging work, reinforcing the cross section corresponding to the extrados of the enlarged tunnel, breaking the old lining, and lining the enlarged tunnel. CONSTITUTION: Prior to excavation, pre-excavation 17 is performed along the extrados 3 of a finally enlarged tunnel profile, and a fixed or movable shield 60 is provided so as not to obstruct the passing of a rolling stock. Concrete 17 is injected to a cut 17, a protection lining 20 is applied thereto, and a reinforced element is formed according to the property of the soil. The shield 60 is moved to start the excavation from under the oil lining, and waste earth is carried out by a wagon on a track, and a final lining is constructed in the section of the tunnel after the breakage is ended. Accordingly, the enlarging work can be performed while using the old tunnel.</p> |
