| 摘要 |
PROBLEM TO BE SOLVED: To objectively evaluate the stability of a slant face of a rock-bed including a change in the inside state of the rock-bed. SOLUTION: A plurality of geophones 12a, and so on 12e are arranged on a slant face 10 of a rock-bed being an object of observation, and vibrations which are generated ordinarily are observed by individual geophones. By finding planar or cross-sectional vibration characteristics, and comparing the vibration characteristics, relative stability of the slant face is evaluated. Concretely, there are methods of finding planar or cross-sectional vibrational particle loci, and knowing whether or not there are any directivities in the vibrational particle loci, and comparing the magnitudes of their amplitudes, of finding the amplitudes of vibrations, plotting on a co-ordinate plane vbrational energy ratios of a slant face portion of the rock-bed/a base rock portion with respect to the height of the slant face, and comparing the magnitudes of the gradients of their characteristic curves, and of finding a spectrum ratio of the vibrations of the slant face portion of the rock-bed/the base rock portion, and comparing the magnitudes of the amplification ratios of vibrations of a dominant frequency.
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