The critical states of saturated loess soils

This paper presents an experimental investigation on eleven loess soils retrieved from NW China to explore the influence of grading and age on soil mechanics. There are overall consistent characteristics in stress-strain relationship and stress paths for the loess tested though detailed property depends on the combination of vi and p0'. The critical state parameters are quantitatively analyzed against the soil properties. The critic state line (CSL) in p' − q plane is less variable. The M value of specimens tested varies from 1.15 to 1.41 and the corresponding φcs' is between 28.8° and 34.8°, which is not clearly related to the loess grading and plasticity index. In the volumetric plane, the intercept Γ of CSLs varies from 1.63 to 2.17 and the gradient λ of loess fall within a narrow range of λ = 0.08 ± 0.03. The λ linearly increases with the increasing plasticity index Ip. The intercept Γ and gradient λ against grading indices has an overall liner trend, i.e., decrease with the increase of D50 and increase with the increasing Cu and Cc values. The intact loess usually has a higher IB value, roughly between 0.5 and 0.9, indicating a relatively high liquefaction potential.