1. Comparison of Strain-rate Dependent Stress-Strain Behavior from K o -consolidated Compression and Extension Tests on Natural Hong Kong Marine Deposits.
- Author
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Yin, Jian-Hua and Cheng, Chun-Man
- Subjects
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MARINE sediments , *SUBMARINE geology , *OCEAN bottom , *CLAY soils , *MATERIALS compression testing , *SHEAR strength of soils , *SOIL mechanics , *SHEAR (Mechanics) - Abstract
This article presents results from a series of K o -consolidated compression and extension triaxial tests on specimens from undisturbed samples of Hong Kong Marine Deposits (HKMD). To investigate the strain-rate effects, a total of seven K o -consolidated triaxial tests were conducted including four compression tests and three extension tests. After K o -consolidation, the triaxial test specimens were sheared at step-changed axial strain rates under three different confining pressures of 50 kPa, 150 kPa, and 400 kPa, respectively. The step-changed strain rates were applied in the following order: +2%/h, +0.2%/h, +20%/h, -2%/h (unloading) and +2%/h (reloading) for the four compression tests and -2%/h, -0.2%/h, -20%/h, +2%/h (unloading) and -2%/h (reloading) for the three extension tests. The results are reported and analyzed in the paper. The results show that the strain rate effects, the stress-strain characteristics, and the effective stress paths of the specimens for tests in a compression state are different from those for tests in an extension stage. One order of magnitude increase in axial strain rate causes an average 8.6% increase in undrained shear strength for compression tests and a 12.1% increase for extension tests. It is also found that the failure mode of the specimens in compression is different from that in extension. The stress-strain behavior of specimens shows strain-softening and a clear shear band in compression tests, but strain-hardening without any clear shear band in extension tests for the same absolute value of axial strain. [ABSTRACT FROM AUTHOR]
- Published
- 2006
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