Study on the Static and Dynamic Behavior of the Unsaturated Colluvial Deposit

• Main Authors: Lee, Ying-Tsan, 李膺讚
• Other Authors: Hsu Hai-Lung
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/05201554128506705795

碩士 === 國立交通大學 === 土木工程學系 === 84 === The research is aimed to investigate the effect of undrained dynamic cyclic loading and degree of saturation on the mechanical behavior of colluvial deposit, such as Hu-Ko and Chin-Qua-Shih soil, by conducting experiments of UU triaxial tests and isotropic triaxial consolidation tests. The mode of theundrained cyclic loading is regular sine wave with the frequency of 1 Hz, and the peak amplitude of the wave is 1/6 the peak strength of static undrained triaxial test under the same condition. After being carried out the undrained cyclic loading, the static undrained triaxial test will be applied to the specimen for comparison to the strength of originally static undrained test. The results show that: (1)The undrained triaxial shear strength decreases with increasing degree of saturation. Above 80% degree of saturation, the strength reduction trend becomes gentle. (2)The degree of saturation influences the friction angle of UU condition. When the soil reaches 100% saturation, the friction angle will be close to zero. (3)Dynamic cyclic loading decreases the peak shear strength, friction angle and cohesion of the soil. (4)The shear strength reduction after dynamic cyclic loading (Fred) bear a log-log relationship with the normalized excess pore water prassure excited by dynamic cyclic loading shown as follows： . The relation can be used as a prediction model of in-situ soil strength after earthquake. (5)Degree of saturation influences the soil compression index enormously beyond the extend of double.