Comparison of Strain-rate Dependent Stress-Strain Behavior from Ko-consolidated Compression and Extension Tests on Natural Hong Kong Marine Deposits |
| |
| Authors: | Jian-Hua Yin Chun-Man Cheng |
| |
| Institution: |
a Department of Civil and Structural Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China |
| |
| Abstract: | This article presents results from a series of Ko-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 Ko-consolidated triaxial tests were conducted including four compression tests and three extension tests. After Ko-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. |
| |
| Keywords: | Ko-consolidation marine deposits shear banding strain-rate effects triaxial compression triaxial extension |
| 本文献已被 InformaWorld 等数据库收录！ |
|
