Effect of strain rate on vane shear test
Investigations on the manipulation of strain rate on saturated clay in vane shear test have been carried out over past 60 years. However, the undrained shear strength of vane shear test on cohesive soil considering the change in excess pore pressure under different strain rate remains unknown. Also...
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| Format: | Final Year Project Report |
| Language: | English English |
| Published: |
Universiti Malaysia Sarawak (UNIMAS)
2017
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| Online Access: | http://ir.unimas.my/id/eprint/25645/1/Effect%20of%20strain%20rate%20on%20vane%2024pgs.pdf http://ir.unimas.my/id/eprint/25645/4/John%20Ling%20ft.pdf http://ir.unimas.my/id/eprint/25645/ |
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| Summary: | Investigations on the manipulation of strain rate on saturated clay in vane shear test have been carried out over past 60 years. However, the undrained shear strength of vane shear test on cohesive soil considering the change in excess pore pressure under different strain
rate remains unknown. Also, the variation of strain rate of vane shear test depending on the standards considering the pore water measurement is still questionable. Set of procedure was developed to carry out vane shear test with pore pressure measurement to investigate the effect of strain rates of vane on saturated soil to the undrained shear strength of soil and excess pore pressure at different depth. The soil sample is classified as SILT of very high plasticity (MV) based on British Soil Classification System (BSCS) and elastic silt (MH)
according to Unified Soil Classification System (USCS). The vane shear test was carried out at the depth of 600mm, 750mm and 900mm, while the strain rate varies from 6, 9, 12, 15, 18, 21 to 24 °/min. From the results, the undrained shear strength from same depth is similar and increases with soil depth. Excess pore pressure is dissipated rapidly at the beginning of the vane insertion, and continued for 6 hours for 600mm soil depth and 3 hours for 750mm and 900mm depth to reach peak value before dropped and stabilized.
Excess pore pressure due to insertion and rotation decreases with increasing strain rate.
Most difference between the excess pore pressure due to the vane insertion and rotation and excess pore pressure due to the vane insertion at different strain rate is relatively small.
The undrained shear strength of the soil increases with the degree of rotation until the peak value before remains constant, meanwhile excess pore pressure rises constantly with time, from 0 to 180°. |
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