| 摘要 |
PURPOSE:To enable formation of a large cavity through a single nozzle, by a method wherein a nozzle, through which high pressure excavating water is injected, is installed to the forward end part of an excavation pipe in a manner that it is made movable horizontally and constantly in a discharge direction through a parallel movement mechanism. CONSTITUTION:A nozzle 17b is installed to the forward end of an excavation pipe 15 of a ground improving device through a parallel movement mechanism 41 formed with plural links 41a, 41b, 41c, and 41d. After the nozzle is inserted through an excavated hole down to a specified depth, with the excavation pipe 15 rotated forwardly and reversely, high-pressure excavation water 29 is injected against a wall surface 32a through the nozzle 17b to form a cavity 32. With the backward movement of a wall surface 32a along with excavation, a hydraulic jack 41e is contracted. The nozzle 17b is protruded in a condition that it is maintained in a horizontal direction, and after excavation is completed, a ground improving agent is fed through the excavation pipe 15 to build an artificial ground. |
