A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Strain Rate and Stress Relaxation Effects on Pressuremeter Testing in Clays
This research was undertaken to answer issues related to cavity expansion and in-situ testing using the pressuremeter. Emphasis of the research was placed upon validating the fundamental concepts underlying the cylindrical cavity expansion theory. Test were performed in a cuboidal shear device (CSD) at strain rates of 0.01%, 0.05%, 0.10%, 0.50%, 1.00% and 5.00% per minute on artificially sedimented specimens of kaolin clay and a kaolin-ground silica mixture with a plasticity index in the range similar to most clays. It was found from the experiments that the normalized shear strength (with respect to 0.01%/min) increases linearly with the logarithm of strain rate. The increase in undrained shear strength in the pressuremeter stress path is about 14.3% per log cycle for kaolin clay and 15-3% for the kaolin-silica mixture. The undrained shear strength in the conventional triaxial test was found to increase about 8 to 1O% for a tenfold increase in strain rate. Therefore, it can be concluded that the undrained shear strength increases about 40-50% more in pressuremeter stress path tests than in the triaxial stress path tests. A new state variable, indicative of the fabric of clays is introduced. Based on these concepts and a general failure criterion, a simple model to predict failure parameters of anisotropic clays for many commonly encountered stress paths was developed. The model capability to interpret in situ strength measured under a given stress path and transfer it to another stress path was illustrated. Finally, the ability to obtain failure parameters for any stress path using data from a single CIUC test was demonstrated.
Strain Rate and Stress Relaxation Effects on Pressuremeter Testing in Clays
This research was undertaken to answer issues related to cavity expansion and in-situ testing using the pressuremeter. Emphasis of the research was placed upon validating the fundamental concepts underlying the cylindrical cavity expansion theory. Test were performed in a cuboidal shear device (CSD) at strain rates of 0.01%, 0.05%, 0.10%, 0.50%, 1.00% and 5.00% per minute on artificially sedimented specimens of kaolin clay and a kaolin-ground silica mixture with a plasticity index in the range similar to most clays. It was found from the experiments that the normalized shear strength (with respect to 0.01%/min) increases linearly with the logarithm of strain rate. The increase in undrained shear strength in the pressuremeter stress path is about 14.3% per log cycle for kaolin clay and 15-3% for the kaolin-silica mixture. The undrained shear strength in the conventional triaxial test was found to increase about 8 to 1O% for a tenfold increase in strain rate. Therefore, it can be concluded that the undrained shear strength increases about 40-50% more in pressuremeter stress path tests than in the triaxial stress path tests. A new state variable, indicative of the fabric of clays is introduced. Based on these concepts and a general failure criterion, a simple model to predict failure parameters of anisotropic clays for many commonly encountered stress paths was developed. The model capability to interpret in situ strength measured under a given stress path and transfer it to another stress path was illustrated. Finally, the ability to obtain failure parameters for any stress path using data from a single CIUC test was demonstrated.
Strain Rate and Stress Relaxation Effects on Pressuremeter Testing in Clays
A. Skandarajah (author) / D. Penumadu (author) / J. L. Chameau (author)
1992
265 pages
Report
No indication
English
Soil & Rock Mechanics , Clay , Shear strength , Strain rate , Stress relaxation , Soil mechanics , Pressure measurement , Soil tests , Cavities , Cycles , Estimates , Expansion , Fabrics , Indexes , Mass , Mixtures , Models , Parameters , Paths , Plastic properties , Reduction , Relaxation , Softening , Soils , Test and evaluation , Theory , Transfer , Variables , Yield , Calibration , Deformation , Triaxial stresses , Moisture content , Stress strain relations , Kaolinite , Mechanical properties , Curve fitting , Failure(Mechanics) , Slurries , Computer programs , Pressuremeter tests , Triaxial shear tests , Undrained shear tests , Water content , Geotechnical engineering , STRESS Computer Program , Settlement(Soils)
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