| 摘要 |
<p><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 reducing a workload when switching a kind of fluid to be injected. <P>SOLUTION: A ground improvement device comprises: an injection pipe 20 having an inner pipe flow channel 24a, an intermediate flow channel 25a, an outer flow channel 26a and an upper nozzle space portion 37 with one edge thereof connected to the intermediate flow channel 25a through an upper shield valve 39 as well as the other edge thereof connected to the outer flow channel 26a through a lower shield valve 36; and an upper nozzle 38 which is arranged on a side surface of a lower edge portion of the injection pipe 20 and injects a hardening material flowing in the inner flow channel 24a as well as high pressure fluid flowing the upper nozzle space portion 37. The upper shield valve 39 is opened when the fluid pressure in the intermediate flow channel 25a is higher than the fluid pressure in the upper nozzle space portion 37. The lower shield valve 36 is opened when the fluid pressure in the outer flow channel 26a is higher than the fluid pressure in the upper nozzle space portion 37. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
