One dimensional normal consolidation line equation

Many empirical equations have been proposed in the past to predict the parameters of the one-dimensional normal consolidation line (1D-NCL) for soils. However, applications of these equations are limited to specific range of pressure and plasticity soils. General empirical equations for 1D-NCL for large range of pressure and plasticity soils are presented in this study. It is assumed that the 1D-NCL has up to three slopes and these slopes start at different stresses depending on liquid limit (LL) of soils. The 1D-NCL of 59 different soils for a large range of LL (19-520%) was used to establish the initial part of 1D-NCL. The soils were categorized based on their LL into two groups: (i) LL < 110% and (ii) LL > 110%. The equations for initial part of 1D-NCL were compared with the previous empirical 1D-NCL equations. The comparisons showed that the new 1D-NCL equations have a better agreement with tests results, especially for highly plastic soils. Moreover, two soils with different plasticity were used to verify the new 1D-NCL equations. The verifications showed a good agreement between the experimental and the predicted results.