| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent the corotation of sediment as much as possible and to widen an agitation range without tentatively pulling a drilling shaft upwards from a ground surface. <P>SOLUTION: On a drilling shaft 6, a drilling blade 7 is provided on the lower end and agitation blades 8 are disposed in a plurality of stages in the vertical direction above the drilling blade. The two drilling shafts are arranged side by side, the drilling blade includes a lower part drilling pawl 26 for drilling toward a lower part and a side part drilling pawl for drilling toward a side part, and the agitation blade is projected in a radial direction from the drilling shaft and includes a side part drilling pawl 21 at the distal end in the radial direction. Two each of the agitation blades are provided at an interval in the circumferential direction of the drilling shaft in each of the plurality of stages. The height position of the agitation blade of one drilling shaft is roughly the same as the height position of the agitation blade of the other drilling shaft, a part of the rotating track of the agitation blade of one drilling shaft and a part of the rotating track of the agitation blade of the other drilling shaft overlap, and the rotating direction of one drilling shaft is opposite to the rotating direction of the other drilling shaft. <P>COPYRIGHT: (C)2012,JPO&INPIT |
