| 摘要 |
PROBLEM TO BE SOLVED: To measure the gaps (air bubbles) in the grout charged in a sheath pipe from the outside of the sheath pipe after the sheath pipe is filled with the grout. SOLUTION: In Fig. (a), two electrodes 112 and 114 provided to the outside of the sheath pipe 140 constituted of an insulator are shown and a capacitor is constituted by the electrodes 112 and 114 through the sheath pipe 140, the grout or the like. Therefore, when high frequency is applied to the electrode 112 from an oscillator 102, the high frequency can be received from the electrode 114 through the grout in the sheath pipe. The received high frequency is changed by the state of the grout. The high frequency received by the electrode 114 is amplified by an amplifier 104 to be detected as output voltage V. This output voltage V is changed by the state in the sheath pipe (the gaps in the grout or the position of a PC steel material). COPYRIGHT: (C)2006,JPO&NCIPI
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