| Summary: | 碩士 === 國立中央大學 === 土木工程研究所 === 99 === The purpose of this study is to do a basic research of sound waves and vibration waves for warning signals of slope failure. Three kinds of material such as Silou sand, gravel and artificial rock were used to perform a series of shear tests and friction tests by using direct shear apparatus under stress control condition. In this study, to avoid the disturbances of vibration and noise during the shearing process, an air cylinder was used to apply the shearing or frictional forces in several steps until the failure of specimens occur. The sound and vibration signals were both analyzed by using the Fast Fourier Transform through the FAMOS software to represent the signals in frequency domain.
The experimental data of shear and friction tests showed that the apparent frequency of sand is lower than 30 Hz and the apparent frequency of gravel is located between 500~840 Hz. According to the experimental results, the shearing information of the material could be distinguished by using the apparent frequency mentioned previously. In addition, the sound signals kept some constant and small values continuously and then some burst signals occurred at the moment of failure. However, the values of acceleration increased gradually before yielding and then some apparent signals occurred. Therefore, an early warning system of monitoring the slope failure can be established by using the combination of the information mentioned before to decrease the damage of disaster.
|
|---|
