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Resistance of full-flow penetrometers in rate-dependent and strain-softening clay.
- Source :
-
Géotechnique . Mar2009, Vol. 59 Issue 2, p79-86. 8p. 1 Black and White Photograph, 2 Charts, 6 Graphs. - Publication Year :
- 2009
-
Abstract
- Accurate determination of in situ shear strength using full-flow penetrometers (cylindrical T-bar and spherical ball) requires thorough investigation into soil characteristics such as strain rate dependency and strain softening, which have been shown to have a significant influence on the resistance factors relating penetration resistance to the soil shear strength measured in laboratory tests. In this paper, these effects have been quantified using a large deformation finite element technique, modelling both the strength enhancement owing to high strain rate and gradual degradation of soil during penetration disturbance. A parametric study confirmed that the separate factors quantifying effects of high strain rate and partial softening may be multiplied together to predict the combined effect, to derive a resistance factor for a given soil. Simple expressions are presented allowing the resistance factors for T-bar and ball penetrometers to be expressed as a function of rate and strain-softening parameters. By considering average strength conditions during penetration and extraction of these full-flow penetrometers, an approximate expression is derived that allows estimation of the hypothetical resistance factor with no strain-softening, and hence an initial estimate of the rate-dependency of the soil. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00168505
- Volume :
- 59
- Issue :
- 2
- Database :
- Academic Search Index
- Journal :
- Géotechnique
- Publication Type :
- Academic Journal
- Accession number :
- 39795404
- Full Text :
- https://doi.org/10.1680/geot.2007.00164