| 摘要 |
PURPOSE:To completely eliminate vibration and noise as well as lessen the excavating volume of the ground by a method in which excavation is made by water jet, the excavation muck is discharged along the inner surface of a steel pipe by air, and the steel pipe is allowed to settle under its own weight. CONSTITUTION:An annular tip frame 2, a jet pipe 9, and an air pipe 10 are attached to a steel pipe 1. Water jet is jetted from the jet pipe 9 to generate a water jet stream along a trench formed in the annular tipe frame 2, and thereby excavation is made for the ground below the cutting edge of the steel pipe 1. The excavation muck is also discharged upwards from a water flow port 5 formed in the upside of the annular tip frame 2 on the water fit stream. The muck is then discharged in an air-lifted state along the inner surface of the steel pipe 1 by means of air jet stream from the air pipe 10 provided on the upside of the annular tip frame 2. The steel pipe 1 provided with a rotary means is allowed to settle as the excavation proceeds. |
