Friction and maximum dilatancy angles of granular soils incorporating low plastic fines and depositional techniques effects

Abstract

This paper addresses the effects of over consolidation ratio (OCR = 1–8), low plastic fines content (Fc = 0–40%) and depositional techniques (DFP and WD) on the stress-strain and volume change behaviours as well as maximum dilatancy, peak-state friction, critical state friction and excess friction angles through two series of drained triaxial compression tests. The first one, emphasizing the effect of the OCR and the second one analysing the influence of Fc on the mechanical behaviour of Chlef sand and Chlef sand-silt mixtures, respectively. All specimens were prepared at a medium density (Dr = 53%) and subjected to a confining pressure (σ′3 = 0.1 MPa). The obtained results indicate that the increase in the fines content of the DFP specimens leads to a decrease in the deviatoric stress and dilative character at the same axial strain, however, the reverse trend is observed for the WD ones. Moreover, it is observed that the deviatoric stress generally increases with the increasing of the OCR for both depositional techniques and the DFP specimens prepared exhibit higher values of the shear strength than the WD ones. Furthermore, the results show that Fc, OCR and depositional techniques influence significantly the mechanical characteristics (ϕ′ps, ϕ′cs, ψmax and ϕ′ex).