| 摘要 |
[Problem] To increase the diameter of an improved-soil column without sacrificing the advantages unique to dry jet mixing in a dry jet deep mixing method. [Solution] The problem can be solved by drilling/inserting an agitation shaft (10) into the area of ground for improvement while rotating the shaft around the center thereof, and during the process also spraying a fluidity improvement agent from a second jet nozzle (16) provided on the tip of the agitation shaft (10), agitating/mixing the in-situ soil and the fluidity improvement agent using rotating agitation blades (13, 14), then withdrawing the agitation shaft (10) from the area of ground for improvement while rotating the shaft around the center thereof, and during the process spraying powdered solidification material from a first jet nozzle (15) provided on the rear in the direction of rotation of the upper agitation blades (13, 14), agitating/mixing the in-situ soil (G) and the powdered solidification material using the rotating agitation blades (13, 14), and thereby creating a columnar solidified body (CB). |
