本研究主要利用微音器及加速度計量測波傳訊號，模擬岩石層面或石塊錯動產生位移時音波與加速度的情形。試驗中係利用氣動式直剪試驗儀，以應力控制方式施加水平向推力，進行一系列定荷重之摩擦試驗。波傳訊號經濾波後，擷取所需之階段，並與位移進行比較。 試驗結果顯示：當位移產生時，摩擦振動所造成之音波訊號有較明顯的聚集波形，加速度則因延時較長，易與下一波形重疊導致不易判斷波形的發生與結束時間。位移量愈大時，產生之音壓也愈大；當位移量愈大時加速度亦會增大，但所得結果並不如音壓值來得清楚。因受正向應力束制關係，當層面發生位移而產生之音壓較為平均。經正規化處理去除正向應力之因素，音壓與位移關係呈現較集中的分佈。在發生破壞前若量測到波傳訊號，此刻之應力狀態已達到降伏狀況，若摩擦力持續增加則會發生瞬間的大量位移而破壞。降伏摩擦力與破壞摩擦力比約為0.8。因此如量測到音波訊號時，立即對此岩層或邊坡發出警訊，可降低災害的損失，本研究成果對防災應有助益。 This research used the sound and vibration wave signals measured from the microphone and accelerometer to investigate the properties of the sound waves and vibration waves generated by the displacement between two rock specimens. From the results of experiments, the sound waves have clearer signal properties than those of the vibration waves. When the rock specimens slide for a larger displacement, the sound pressures became greater. However, the results of the acceleration were not so good as that of the sound pressure. Furthermore, owing to the constrain of the normal stresses, failure occurred suddenly, and the uniform sound pressures were generated. By normalizing the sound pressures, some concentrated relationships between sound pressures and displacement were found. If the sound wave signals were measured, the frictional properties would achieve the yield condition. In case the frictional stress increased continuously, the failure will occur suddenly. The ratio between the yield stress and the failure stress is about 0.8. By using the knowledge obtained from this research, we may expect to build a warning system of rock block or stone sliding in the future.
