林道切取りのり面の安定性に関する研究 : 第1報弾性波伝播速度測定器の開発

概要

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This study was initiated to study the possibility of using elastic waves-velocity and attenuation to evaluate the stability of cutting slopes in the forest roads. In this report, an apparatus for measuring the velocity of elastic waves and the results obtained from this apparatus are reported on. This apparatus consists of two vibration pick-ups, amplifiers, wave-form rectifiers which rectify the signal at the balanced output of amplifiers, and an electronic stopwatch which measures the time intervals between the arrival of the first signal of near pick-up and that of the remote one from the impact point. The characteristics of the apparatus are as follows: (1) Up to a time resolving power of 1 $ \mu $sec, the time intervals could be measured by use of the appropriate impact technique. The elastic wave in the soil has a velocity of several ten-hundreds m/sec, so the velocity could be measured with an accuracy of better than 0.1%. (2) The experiment was carried out by filing a wooden bin with decomposed granite, and from this, it became clear that the amount of scatter in the measured values was very small (coefficient of variation: 0.05), at distances above 20cm between the two pick-ups.
九州大学の論文