A calibration test on new cyclic triaxial apparatus and some liquefaction tests.

• Main Authors: CHIEN, YU-HO, 錢有和
• Other Authors: HSIAO, DARN-HORNG
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/3867nt

碩士 === 國立高雄應用科技大學 === 土木工程與防災科技研究所 === 106 === In this study, six mixtures of Kaohsiung sand and soil were added with different proportions of fine aggregate and different relative densities to conduct some dynamic triaxial tests in order to investigate the effect of the content of fines on soil liquefaction resistance. Some research issues were studied such as amplitude's influence on relative density and soil liquefaction resistance, and effect of amplitude on soil liquefaction resistance and critical state parameters. The results of dynamic triaxial test showed that under the condition of 0% of the fine material and 30% of the relative density, the results four of different amplitude were obtained, which shows that the cyclic number required for the liquefaction of the sample gradually decreased with increasing amplitude. If amplitude equaling to 0.2 kN and 0.4 kN, it is found that the axial stress of amplitude = 0.4 kN is larger than that of amplitude = 0.2 kN and the corresponding axial strain is ranged from 1% to -6%. By plotting the relationship between the cyclic number and the relative density under the two amplitude amplitudes, we can find that when the amplitude is increased, both the initial liquefaction response (cyclic number) and the strain 2.5% response (cyclic number) are apparently reduced, indicating that the soil reduced resistance to liquefaction. With the plot of the cyclic number versus the criticality parameter, as the amplitude increases from 0.3 to 0.4, the cyclic number drastically decreases, with the trend line falling from a high slope to a gentler straight line. When the relative density of the test reaches to 70%, and 0% and 15% of fines (CSRs are set to 0.45 and 0.4, respectively), the difference of axial difference stress of fine material 15% is smaller than that of pure sand and conversely the axial strain ratio pure sand has a greater stress than 15% fines. As far as the pore water pressure is concerned, the number of reflections required for the fine material 15% is more difficult to liquefy than pure sand.