STIRRING HEAD OF SOIL IMPROVEMENT DEVICE

PROBLEM TO BE SOLVED: To provide a stirring head capable of stirring and mixing excavated soil with hardener efficiently at high speed. SOLUTION: A soil improvement device is so constituted that a stirring head 20 loaded to an excavation shaft 10 equipped with an inside shaft 12 rotating in the opposite direction and an outside shaft 11 and for stirring and mixing excavated soil with hardener in an excavated hole is equipped with an upper stirring section 30 and a lower stirring section 40. In that case, the upper stirring section 30 is equipped with inside stirring wings 31 rotating together with the inside shaft 12, outside stirring wings 32 rotating together with the outside shaft 11 and arranged so as to surround rotational loci of the inside stirring wings 31 with the loci of the inside stirring wings and vertical stirring wings 33-1-33-5 hung down from the lower edges of the outside stirring wings 32. The lower stirring section 40 is equipped with the lower end stirring wings 41 rotating together with the inside shaft 12 and erected stirring wings 42-1-42-4 erected from the upper edges of the lower end stirring wings 41. The vertical stirring wings 33-1-33-5 and erected stirring wings 42-1-42-4 overlap the extension areas in the vertical direction and, at the same time, the rotational loci pass each other.