| 摘要 |
<p>PROBLEM TO BE SOLVED: To accurately specify unstable block field by measuring the horizontal component of fine move constantly at a plurality of depths in a rock ground and specifying an unstable block field part according to a vibration form based on the measurement. SOLUTION: A drilling hole 1 is punched to the inclined surface of a rock ground that may collapse, and a compact slight movement meter is inserted inside and is fixed to a hole wall 1a at a specific depth. Then, the constant slight movement at that depth is measured and a horizontal constituent is amplified, and the dominant frequency of the horizontal vibration and its amplitude (peak value) at a measurement point are calculated and recorded by a frequency analyzer. This sort of measurement and operation/recording are made by successively changing the installation depth of the compact slight movement meter, namely the depth of measurement points A-D, and stability and instability at the measurement points A-D are judged from the difference in relative vibration property in a depthwise direction (relative value of a prominent frequency and its peak value), thus specifying an unstable block field part.</p> |
