| 摘要 |
PURPOSE:To accurately confirm a support layer, by a method wherein, boring is effected by means of an auger, the intensity of vibration of frequency with a specified range generated to the auger is measured, and a change in the intensity of vibration is compared with a diagram of the quality of soil. CONSTITUTION:When a pile hole 6 is execavated by means of an auger 3, vibration is generated to the forward end of the auger 3 by the cutting resistance of a ground, the vibration is transmitted to a vibration sensor 7, and after the vibration is converted into an electric signal by the vibration sensor 7, the electric signal is transmitted to a vibration measuring device 8. In the vibration measuring device 8, only a signal in the vicinity of 5-10Hz is selected by a band-pass filter 10. The signal passes through an amplifier 11 and an all wave rectifier 12, a peak value is faded out 13, and the signal is recorded in a recorder 14 and is displayed in a display unit 9. Excavation is continued while a quality diagram of soil and the depth of a bored holes are referred to each other, and when the auger 3 is lowered doen to a support layer, the intensity of vibration in the vicinity of frequency of 5-10Hz generated to the auger 3 is increased, and the intensity is displayed in the display unit 9 for confirmation. |
