| Summary: | 碩士 === 國立臺灣大學 === 土木工程學研究所 === 91 === The problem of ground vibration at TSIP (Tainan Science-based Industry Park) that will be induced by future operation of the THSR (Taiwan High Speed Rail) is an important issue. Therefore, a group pile foundation was constructed by the National Science Council to perform vibration tests to thoroughly investigate the vibration characteristics of ground at TSIP. In this thesis, results of single pile vibration test and associated numerical analysis by using the computer program FLAC (Fast Lagrangian Analysis of Continua) are presented.
For the single pile vibration test, the forced vibration test by using an eccentric shaker, as well as an impact test by using an 8-ton drop hammer, were conducted in the field. For both tests, the ground vibration was measured by a series of velocity sensors deployed at various distances form the test pile. Through spectral analyses, the vibration and the normalized dynamic response function of ground and pile head were deduced. And then the attenuation coefficient of ground vibration with respect to distance was also regressed. According to analysis results, the attenuation coefficient in forced vibration test is fundamentally increased with vibrational frequency, but it seems no relation to frequency in impact test. Furthermore, in the impact test, the horizontal response becomes larger at a distance of 40 m from the pile foundation.
In numerical analysis, an axisymetrical model with quiet boundary is adopted for simulation analysis. When compared to the results of tests, the simulation of forced vibration test is good in the frequencies less than 10 Hz, but some differences exist at higher frequencies. As for the impact test, only the frequency contests of the ground vibration can be simulated by the numerical analysis. The time-history responses can not be well traced.
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