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 v_i 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 φ_cs^' 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 I_p. 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 C_u and C_c values. The intact loess usually has a higher I_B value, roughly between 0.5 and 0.9, indicating a relatively high liquefaction potential.