| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a ground improvement device, which improves the ground by injecting high pressure fluid through a tip of a multiple pipe, capable of improving cleaning efficiency of a lower portion of a nozzle to promote efficiency of a cleaning work. <P>SOLUTION: A ground improvement device 1 comprises: an injection pipe 20 having an inner pipe flow channel 24a as well as an outer flow channel 26a surrounding the outside of the inner pipe flow channel 24a; and an upper nozzle 38 with a duplex type nozzle to inject a hardening material flowing in the inner pipe flow channel 24a as well as high pressure air flowing in the outer pipe flow channel 26a. A diversion space portion 31, which is the lowest portion of the outer flow channel 26a, is arranged lower than a height of a lower nozzle 35 and communicated with the lower nozzle 35 through a nozzle communicating passage 33 extended upward toward the lower nozzle 35 and thereby cleaning the lower nozzle 35 from a lower side by supplying cleaning fluid instead of the high pressure air to the outer flow channel 26a. <P>COPYRIGHT: (C)2012,JPO&INPIT |
