| 摘要 |
PROBLEM TO BE SOLVED: To efficiently crush concrete using a concrete drilling method and to prevent peripheral concrete from being adversely affected by the collision of a weight. SOLUTION: First, a Hume pipe 20 whose impact strength is about equal to or less than the impact strength of concrete is erected in a place where concrete 90 is to be placed. Next, concrete 40 is placed around the Hume pipe 20. After the placed concrete 40 hardens, a chisel 70 is repeatedly dropped onto the Hume pipe 20 and the concrete 40 around it from above so as to crush the Hume pipe 20 and the concrete 40 around it to drill a hole. More specifically, a casing tube 50 is rotated and pushed into the concrete 40 around the Hume pipe 20 and the chisel 70 is dropped into the casing tube 50 to crush the Hume pipe 20 and the concrete around it.
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