| 摘要 |
PURPOSE:To reasonably perform the supplying operation of sand by a method in which on the way of discharging wet sand while supplying compressed air into a hollow pipe, the pulling of the hollow pipe is stopped, water is sucked up at the lower inside of the hollow pipe, and compressed air is discharged and wet sand is supplied. CONSTITUTION:Compressed air is supplied through a compressed air supply and discharge pipe 3 into a hollow pipe 3. During the period, the hollow pipe 1 is pulled up, and wet sand 2 is discharged from the lower end of the pipe 1. Under the condition that wet sand 2 is left in the pipe 2, the pulling of the pipe 2 is stopped, and water is temporarily sucked up from a strainer 5 provided to the lower part of the inside of the pipe 1, compressed air is discharged from the pipe 1, and wet sand 2 is supplied from a hopper 6 into the pipe 2. By reducing the water content of the wet sand 2 in this way, a frictional force is produced between the sand 2 and the inner wall of the pipe 1. Therefore, the back flow of soil into the pipe 1 can be prevented and reasonable operations can be attained. |
