DEVICE AND METHOD FOR INSPECTING FILLING STATE OF BACK- FILLING MATERIAL

摘要

PROBLEM TO BE SOLVED: To easily measure the filling state of a back-filling material around a laid pipe with high accuracy. SOLUTION: In a state where an impedance head 12 installed in a vibrator 11 is press-contacted with the inner peripheral surface of a helix tube 20, the vibrator 11 is vibrated by a sine wave alternating current voltage to transmit the vibration of the vibrator 11 to the helix tube 20, thereby the helix tube 20 is vibrated. The impedance head 12 detects the magnitude of an external force added to the helix tube 20 by the vibrator 11 to output it to a calculation control part 17 through a charge amplifier 15 and it also detects the accelerated velocity of the vibration generated in the helix tube 20 to output it to the calculation control part 17 through a charge amplifier 16 by which the accelerated velocity is converted into the velocity of the vibration. The calculation control part 17 calculates a machine admittance which is a vibration velocity per unit external force based on the external force added to the helix tube 20 and the velocity of the vibration generated in the helix tube 20.