| 摘要 |
PROBLEM TO BE SOLVED: To provide a preceding excavation plate member which facilitates attachment/detachment thereof to/from a columnar soil improving agitation device, enables lifting of a considerable amount of sediment excavated by the columnar soil improving agitation device, and achieves efficient preceding excavation of a preceding hole. SOLUTION: The preceding excavation plate member 10 is mounted on the columnar soil improving agitation device 13 formed of a rotating shaft 14, an excavation blade 15 arranged on an extreme tip of the rotating shaft 14, double staged agitation blades 16 arranged on an end of the rotating shaft 14, and a corotation prevention blade 17, and it is for use in preceding excavation prior to construction of a columnar soil improving pile. The preceding excavation plate member 10 consists of a pair of unit excavation plates 18 whose shapes in plan are each formed like a semicircular band plate having an external diameter similar to the external diameter of the agitation blade 16 and an internal diameter larger than the external diameter of the rotating shaft 14. Further each unit excavation plate 18 is mounted on the rotating shaft 14 in a spiral direction around the same by connecting one edge 18a to the upper stage agitation blade 16 and an intermediate portion 18b to a lower stage agitation blade 16, respectively. COPYRIGHT: (C)2009,JPO&INPIT
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