| 摘要 |
PROBLEM TO BE SOLVED: To improve the strength of the weak portion of the arch concrete near an end plate by placing ready-mixed concrete between a tunnel and an arch center, horizontally inserting a vibrator into the ready-mixed concrete from insertion ports formed on the end plate, and applying vibrations to compact the concrete. SOLUTION: Many insertion ports 5 openable or closeable by lids are bored at the prescribed intervals from the shoulder section to top end section of an end plate 4 arranged at the end section, i.e., end side, of the placing space 3 between a tunnel and an arch center arranged inside it. After the end side of the placing space 3 is closed, ready-mixed concrete is injected, the lid of an insertion port 5 is opened, a vibrator 6 is horizontally inserted, and vibrations are applied to the ready-mixed concrete to compact it. The excess water of the ready-mixed concrete and an unnecessary portion such as mortar having much moisture flow to the outside of the end plate 4 at this time. The compacting of the end plate 4 side and the compacting from a shoulder section to the vicinity of a top end section can be easily conducted with the end plate 4 kept fitted, and the strength of the weak portion of arch concrete near the end plate 4 is improved.
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