土石流運動有明顯之聲音產生，本研究先在實驗室進行定性研究，量測不同材質顆粒運動所發出的聲音，分析其音壓值找出顆粒聲音頻率特性與能量大小關係。本研究運用二組實驗，分別使用玻璃珠、BB 彈、細磨石與蛙沙，找到其顆粒固定頻率。比較不同材質撞擊產生音壓能量依序為玻璃珠最大，其次BB 彈，最小為細磨石。材質相同時粒徑越大，則能量越強。因運動狀態不同垂直運動，聲音發聲點在圓筒底部，及蛙沙在速度慢時摩擦底面、邊壁與兩端堆積發聲，在速度快時則顆粒互相碰撞發聲。蛙沙能量圖形為向上凹曲線，以加速度在1.25G 時能量最小。 The motion-induced acoustic signals for different granular particles are experimentally measured in this study. The variation of sound pressures and the corresponding peak frequencies under different forcings are analyzed. Two groups of test are adopted for the granular materials such as the glass bead, the polypropylene bead, the mill stone and the frog sand. The glass beads generate largest impacting sound pressure, the polypropylene beads in between, and the sound pressure for the mill stones is smallest. The sound pressure increases with particle size for the same material. The sound pressure for frog sand exhibits a peak value at the acceleration of 1.25G.
