Correlations between Low and High Strain Stiffnesses of few Natural and Artificial Cohesive Soils

Saeed Ahmad, M. Hesham El Naggar, Aly Ahmed, Deyab Gamal El-Dean

In the proceedings of GeoSt. John's 2019: 72nd Canadian Geotechnical Conference

Session: Posters

ABSTRACT: Piezoelectric ring actuator-oedometer setup (PRA) was used to measure the shear wave velocity (Vs) and hence the dynamic shear modulus (Gmax) of few natural/artificial cohesive soils at various applied pressures. The oedometric stiffness (from 1D consolidation data) were determined simultaneously with Vs measurements. The soils were subjected to isotropically consolidated undrained (CIU) triaxial tests to evaluate their undrained static stiffness at different confining pressures. Low stain stiffnesses obtained from PRA setup were correlated to the high strain stiffnesses obtained from oedometer and CIU tests. Some practical correlations (stiffness ratios) between low and high strain stiffnesses for the tested soils were proposed which can be used to estimate dynamic stiffness for similar soils.

RÉSUMÉ: La configuration actionneur-oedomètre à anneau piézoélectrique (PRA) a été utilisé pour mesurer la vitesse des ondes de cisaillement (Vs) et donc le module de cisaillement dynamique (Gmax) de quelques sols cohérents naturels / artificiels à diverses pressions appliquées. La rigidité oedométrique (à partir des données de consolidation 1D) a été déterminée simultanément avec les mesures de Vs. Les sols ont été soumis à des essais triaxiaux non drainés à consolidation isotrope (CIU) afin d'évaluer leur rigidité statique non drainée à différentes pressions de confinement. Les faibles raideurs aux taches obtenues à partir de la configuration PRA ont été corrélées aux fortes raideurs de contrainte obtenues lors des tests oedometer et CIU. Certaines corrélations pratiques (rapports de rigidité) entre les rigidités de déformation faible et élevée pour les sols testés ont été proposées, qui peuvent être utilisées pour estimer la rigidité dynamique de sols similaires.

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Cite this article:
Saeed Ahmad; M. Hesham El Naggar; Aly Ahmed; Deyab Gamal El-Dean (2019) Correlations between Low and High Strain Stiffnesses of few Natural and Artificial Cohesive Soils in GEO2019. Ottawa, Ontario: Canadian Geotechnical Society.

@article{Geo2019Paper209,author = Saeed Ahmad; M. Hesham El Naggar; Aly Ahmed; Deyab Gamal El-Dean,title = Correlations between Low and High Strain Stiffnesses of few Natural and Artificial Cohesive Soils,year = 2019}