- Title
- Strain rate calculation in consolidated undrained triaxial testing and implications on design strengths
- Creator
- Burton, G. J.; Airey, D. W.
- Relation
- 11th Australia - New Zealand Conference on Geomechanics (ANZ 2012). ANZ 2012 Conference Proceedings of the 11th Australia - New Zealand Conference on Geomechanics (Melbourne 15-18 July, 2012) p. 1063-1068
- Publisher
- Australian Geomechanics Society
- Resource Type
- conference paper
- Date
- 2012
- Description
- Triaxial testing is probably the most widely used laboratory test by geotechnical engineers to determine the stress-strain-shear strength behaviour of saturated soils. Conventional testing requires back pressure saturation to achieve a degree of saturation as close as possible to unity. Following saturation, the sample is typically isotropically consolidated by either increasing the cell pressure of reducing the back pressure (ideally increasing the cell pressure to prevent dissolution of the air). The results of the consolidation phase are then used to select an appropriate strain rate - the rate of axial deformation. The requirements for dissipation of pore pressure during a drained test (CD) are widely recognised; equally important are the rates of axial straining in a consolidated undrained (CU) test and the relation of these strain rates to the anticipated rates of failure in the field. A comparison of current Australian Standard (AS) "informative" method for determination of the strain rate in undrained shearing is made with the American and British Standards. The AS suggests significantly higher strain rates, which will lead to higher undrained strengths between lab and field, an effect which is not well understood. Finally the AS rate is too fast to allow pore pressure equalisation prior to failure, and any test involving different stages pre-failure must use a significantly slower axial strain rate.
- Subject
- triaxial; stress-strain; shear strength; rate effects
- Identifier
- http://hdl.handle.net/1959.13/1339998
- Identifier
- uon:28382
- Identifier
- ISBN:9780646543017
- Language
- eng
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