Drained and undrained shear strenght of silty sand: effect of the reconstruction methods and other parameters

Abstract

The effects of confining pressure, relative density and sample preparation methods on the shearing strength of Chlef sand were studied in this article. For this purpose, the results of drained and undrained monotonic triaxial compression tests performed on samples with initial density of 0.29 and 0.80 under initial confining pressures ranged from 50 to 200 kPa are presented.  The specimens were prepared by two depositional methods namely dry funnel pluviation and wet deposition.  It was found that there was a marked difference in the undrained behavior even though the density and stress conditions were identical. The conclusion was that the soil fabric was responsible for this result. The results indicated also that at low confining pressures, the specimens reconstituted by the wet deposition method exhibited complete static liquefaction (zero effective confining pressure and zero stress difference). As confining pressures and densities were increased, the effective stress paths indicated increasing resistance to liquefaction by showing increasing dilatant tendencies. The same trends were observed in drained tests results in the form of an increase in the volumetric strain and the rapid transition from the contractancy phase to the dilatancy phase.

Keywords

• liquefaction, sand, drained, undrained, dry funnel pluviation, wet deposition, confinement, density, residual strength, volumetric strain