Abstract
With an objective to measure at high accuracy the positions and sizes of cracks existing in rocks, a theoretical study has been carried out on a method which utilizes initial movement characteristics of P-wave. The P-wave which diffracts and propagates at a crack tip has a characteristic that its phase may reverse according to the positional relationship between vibration transmitting and receiving points. This positional relationship is decided by the Poisson ratio of media alone. Therefore, when the P-wave is measured while the vibration transmitting and receiving points are moved sandwiching a crack, the polarity of received waveform is changed from negative to positive at a certain position as a boundary. In order to measure this change at high accuracy, an elastic wave of high frequency is required, but it is not easy to obtain the wave in situ. In contrast, utilizing the initial movement polarity can not only identify the change in the polarity, but also perform measurement at high accuracy. The present study discussed a case where cracks are parallel with a free surface and a case where the cracks have angles with the free surface, whereas it was shown that positions of the upper and lower tips
More>>
Tomishima, Y
[1]
- National Institute for Resources and Environment, Tsukuba (Japan)
Citation Formats
Tomishima, Y.
Measurement of crack in rock using transmitted elastic wave; Toka danseiha ni yoru ganbannai kiretsu keisoku.
Japan: N. p.,
1997.
Web.
Tomishima, Y.
Measurement of crack in rock using transmitted elastic wave; Toka danseiha ni yoru ganbannai kiretsu keisoku.
Japan.
Tomishima, Y.
1997.
"Measurement of crack in rock using transmitted elastic wave; Toka danseiha ni yoru ganbannai kiretsu keisoku."
Japan.
@misc{etde_622654,
title = {Measurement of crack in rock using transmitted elastic wave; Toka danseiha ni yoru ganbannai kiretsu keisoku}
author = {Tomishima, Y}
abstractNote = {With an objective to measure at high accuracy the positions and sizes of cracks existing in rocks, a theoretical study has been carried out on a method which utilizes initial movement characteristics of P-wave. The P-wave which diffracts and propagates at a crack tip has a characteristic that its phase may reverse according to the positional relationship between vibration transmitting and receiving points. This positional relationship is decided by the Poisson ratio of media alone. Therefore, when the P-wave is measured while the vibration transmitting and receiving points are moved sandwiching a crack, the polarity of received waveform is changed from negative to positive at a certain position as a boundary. In order to measure this change at high accuracy, an elastic wave of high frequency is required, but it is not easy to obtain the wave in situ. In contrast, utilizing the initial movement polarity can not only identify the change in the polarity, but also perform measurement at high accuracy. The present study discussed a case where cracks are parallel with a free surface and a case where the cracks have angles with the free surface, whereas it was shown that positions of the upper and lower tips of a crack, and length of the crack can be measured accurately. 4 refs., 5 figs.}
place = {Japan}
year = {1997}
month = {Oct}
}
title = {Measurement of crack in rock using transmitted elastic wave; Toka danseiha ni yoru ganbannai kiretsu keisoku}
author = {Tomishima, Y}
abstractNote = {With an objective to measure at high accuracy the positions and sizes of cracks existing in rocks, a theoretical study has been carried out on a method which utilizes initial movement characteristics of P-wave. The P-wave which diffracts and propagates at a crack tip has a characteristic that its phase may reverse according to the positional relationship between vibration transmitting and receiving points. This positional relationship is decided by the Poisson ratio of media alone. Therefore, when the P-wave is measured while the vibration transmitting and receiving points are moved sandwiching a crack, the polarity of received waveform is changed from negative to positive at a certain position as a boundary. In order to measure this change at high accuracy, an elastic wave of high frequency is required, but it is not easy to obtain the wave in situ. In contrast, utilizing the initial movement polarity can not only identify the change in the polarity, but also perform measurement at high accuracy. The present study discussed a case where cracks are parallel with a free surface and a case where the cracks have angles with the free surface, whereas it was shown that positions of the upper and lower tips of a crack, and length of the crack can be measured accurately. 4 refs., 5 figs.}
place = {Japan}
year = {1997}
month = {Oct}
}