| 摘要 |
PURPOSE:To increase the cross sectional coefficient and strength of improved ground structure of a round columnar form as well as raise its stability by a method in which a ringed cross section of soil containing unimproved soil inside and an improved ground solidified with an improving agent are concentrically provided. CONSTITUTION:Paired boring and stirring blades 3 are provided at the tip of a hollow rod 2, an injection nozzle 5' is provided inside of the blades 3 and connected with a pathway 4, and air or cement fed are injected from the tip to the outside. In the construction work, the hollow rod 2 is turned to dig out the ground to form a hole 7, during which stirred soil 6 is formed inside the hole 7 by means of air jet from the nozzle 5'. When a given depth is reached, cement is pneumatically sent to the pathway 4 and the hollow rod 2 is pulled up while being turned. Thus, an improved ground 8' is formed. |
