| Summary: | 碩士 === 萬能科技大學 === 工程科技研究所 === 96 === In the study of the operation of high speed railway causing disturbance that makes the soil backfill embankment sink, the utmost consideration must paid to the safety of the passengers. As such, the safety evaluation of the soil backfill embankment during tunnel entrance inspection receives high priority and importance. From the speed-time reflective chart generated from micro-vibrator, and by using Hilbert-Huang Transformation to transform the measured signal from time-frame into frequency, spectrum analysis is conducted by using H/V spectrum, and the results of the analysis is used to understand the effects that high speed railway has on the backfill embankment during high speed operation.
This study aims to understand the effects that are made to the soil by studying the soil’s internal structure after long-term and repeated pounding by the high speed railway’s load. Since the soil would tamp and sink during the tamping process, the property of the soil would change entirely. According to the analysis results of the vibration frequency chart generated by the operation of high speed railway, their distributions are rather similar. The frequency of the high speed railway is between 20HZ~30HZ. The KG value, as calculated by using H/V Spectrum Chart, reveals a reduction from 10HZ to 1HZ. The result indicates that there is a decreasing trend in the magnification of high frequency, which in turn indicates that the backfilled soil is still in the process of being condensed. Even though there is relevance in terms of railway speed, the vibration caused by the high speed during high speed railway operation is conveyed through the soil, thus causing damping effect in the process. Therefore, the expressed frequency is also connected with site effect.
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