CAST-IN-PLACE PILE FORMED BY MIXING AND STIRRING

PROBLEM TO BE SOLVED: To improve the strength of a pile main body part. SOLUTION: When forming a cast-in-place pile 10, a stirring shaft 30 is inserted down to a depth where it reaches a bearing stratum 14 while rotating the stirring shaft 30. At this time, a slurry containing a solidifying material such as cement is injected and supplied into the ground while rotating a stirring and mixing blade 28 to mix and stir the ground soil and slurry together. After that, the stirring shaft 30 is pulled up to form the pile main body part 12 when the slurry is solidified after pulling up the stirring shaft 30 onto the ground side. Before the slurry is solidified, a flexural rigidity reinforcing member 16 is inserted and provided in the pile main body part 12. The slurry to be mixed and stirred with the ground soil is composed in such a way that a ratio of water to cement is less than 60%, viscosity reducing agent is added thereto, and the solidifying material is added thereto by 3 KN or more per unit volume.