| Summary: | 碩士 === 國立中央大學 === 土木工程研究所 === 92 === Cone Penetration Test (CPT) can be operated easily and quickly. CPT is usually applied in investigation of soil classification and soil layer verification. This research used the technique of sound measurement with a small microphone installed in the cone tip to measure the acoustic signal during the penetration of cone tip.
One circular chamber and a movable sand pluviator were used to carry out a series of laboratory cone penetration tests under different relative densities and overburden pressures. The data waa recorded by data acquisition system, and acoustic emission (AE) rate, root mean squar (RMS) of sound pressure and frequency spectrum were analyzed.
From the experimental results, the root mean square of sound pressure and AE rate increased with the increase of average grain size. The influences of average grain size on cone resistance ate small. Furthermore, it is shown that the cone resistance would be increased with the increase of relative density and overburden pressure. However, the root mean square of sound pressure is slightly varied with the change of relative density and overburden pressure. Then the difference between the root mean square of sound pressure and cone resistance under different pressure mode is not great. Besides, the analyses of frequency spectrum of Shiluo Sand showed that the major frequency distribution of these tests are located at the range of 3~4kHz.
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