| 摘要 |
An ultrasonic pulse is applied from a transmission probe for longitudinal waves kept in contact with the external surface of a concrete structure into the interior of the structure, and a reflected wave returning after being reflected by the boundary face of the concrete structure is detected with a reception probe for longitudinal waves kept in contact with the external surface of a concrete structure. As the first peak recognized in the waveform of the reflected wave represents the reaching time T1 of the bottom face echo which has undergone no mode conversion, and the subsequently obtained second peak, in about 1. 3 to 1. 7 times when first peak appeared, represents the reaching time T2 of the delayed echo which has undergone a mode conversion, the sonic velocity ratio R of longitudinal wave to transverse wave is calculated from these reaching times T1 and T2. Then, object physical quantities corresponding to the sonic velocity ratio R are figured out from correlations known in advance regarding the concrete structure between the sonic velocity ratio R and object physical quantities.
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