| 摘要 |
PROBLEM TO BE SOLVED: To provide a head for injecting pressurized liquid from a boring hole in order to disperse soil, which is attached to the end of a drill string including a liquid feeding means for feeding the pressurized liquid. SOLUTION: The head includes a body and an outer wall, and the body has at least one injection nozzle installed therein, which has an insertion port with a diameter of d and extends along an axis x-x'. The body further has a duct forming means which has a central line including a first end connected to the lower end of the liquid feeding means and a second end connected to the injection nozzle in a tangential direction with respect to the axis x-x'. The central line is defined by at least one curved portion having a radius of curvature which is continuously varied. The cross sectional surface of the duct forming means is regularly reduced at least one half of its entire length from a first end to a second end. COPYRIGHT: (C)2004,JPO
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