| 摘要 |
PURPOSE:To allow a sand pile forming tube to be effectively and properly used in soft ground by using a system in which a butterfly valve having a great opening degree, provided at the tip of the hollow tube of the sand pile forming tube, can be exactly airtightly closed when closed. CONSTITUTION:A butterfly valve 4 is provided in the inside of the tip of a hollow tube 1 as the main of a sand pile forming tube, and a rubber seal lever 12 is provided along the peripheral side of the valve plate 5 of the valve 4. Also, the other end of a rope 9 attached to the upside of the valve plate 5 at its lower end is connected to a working machine 10 attached to the wall of the hollow tube above the valve plate. The valve plate 5 is forcibly pulled up to a horizontal closing position by the rope 9 by operating the working machine 10, and the seal lever 12 is pressed on the inner wall of the hollow tube 1 to airtightly close the tip portion of the hollow tube 1. By this, the intrusion of water and soft ground soil into the hollow tube 1 can be prevented in the sand pile forming process where the hollow tube 1 is penetrated to a given depth into the soft ground of the botton under water. |
