| 摘要 |
PROBLEM TO BE SOLVED: To provide a shaft opening structure which can constitute a starting hole or an arrival hole for an excavator. SOLUTION: In the shaft opening structure, an opening steel plate 4 is connected and fixed to an earth retaining wall 2 by means of a connecting steel plate 6 which is arranged so as to enclose the periphery of openings 3 and 5 like a square frame. A sliding steel plate 7 is vertically movably arranged between the earth retaining wall 2 and the opening steel plate 4. By fixing the sliding steel plate 7 and the opening steel plate 4 to each other by means of bolts 10 and nuts 11 to block the opening 5, the interior of the shaft is cut off from the exterior of the same.
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