Some Observations on the Effect of Cyclic Shear Loading Polarity on Reconstituted Silts with Initial Static Shear Stress

D Wijewickreme

In the proceedings of: GeoVancouver 2016: 69th Canadian Geotechnical Conference

Session: SOIL AND TERRAIN CHARACTERIZATION - I Geotechnical Laboratory Testing

ABSTRACT: The effect of cyclic shear loading polarity (direction) on reconstituted natural silt with initial static shear bias () was investigated using the constant-volume direct simple shear (DSS) device. Natural silt used for the present investigation originates from Kamloops benchland deposits, located on the south side of South Thomson River in Kamloops, British Columbia, Canada. Silt specimens, initially consolidated to a target vertical effective stress level with different initial static shear levels were subjected to constant volume cyclic shear loading under different applied cyclic stress ratios and varying cyclic shear loading polarity. Progressive degradation of stiffness and gradual increase of excess pore water pressure were observed for all the tested specimens in spite of variation in initial static shear bias level, applied cyclic stress ratios, and cyclic shear loading polarity. The observed behavior suggested that the tested silt is unlikely to experience flow failure under cyclic loading for various values less than 0.10. The data also revealed that the change in cyclic shear loading polarity would affect the cyclic resistance of the tested material for = 0.05, however, no such affect was observed for = 0.10.

RÉSUMÉ: L'effet de polarité de chargement en cisaillement cyclique (direction) sur limon naturels reconstitués avec partialité de -volume de cisaillement simple direct (DSS) appareil. Silt naturel utilisé pour la présente enquête provient de gisements benchland Kamloops, situé du côté sud de la rivière Thompson Sud à Kamloops, British Columbia, Canada. Spécimens de silt, initialement consolidée à un niveau de contrainte effective verticale cible avec différents niveaux de cisaillement statique initiale ont été soumis à des efforts de cisaillement cyclique à volume constant sous différents appliqués de cisaillement cyclique des ratios et polarité de chargement en cisaillement cyclique variable. Une dégradation progressive de la rigidité et une augmentation graduelle de la pression d'eau interstitielle ont été observées pour tous les spécimens examinés en dépit de la variation dans le niveau de polarisation de cisaillement statique initiale, appliqué les ratios des contraintes cycliques, et polarité de chargement en cisaillement cyclique. Le comportement observé a suggéré que l'essai s'il est peu probable que le limon expérience Panne débit sous chargement cyclique pour diversrévélé que le changement de polarité de chargement en cisaillement cyclique affecterait la résistance cyclique du

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Cite this article:
D Wijewickreme (2016) Some Observations on the Effect of Cyclic Shear Loading Polarity on Reconstituted Silts with Initial Static Shear Stress in GEO2016. Ottawa, Ontario: Canadian Geotechnical Society.

@article{3739_0727185219,author = D Wijewickreme,title = Some Observations on the Effect of Cyclic Shear Loading Polarity on Reconstituted Silts with Initial Static Shear Stress,year = 2016}