Soft computing of the recompression index of fine-grained soils

Consolidation settlement is a phenomenon happens in saturated fine-grained soils when subjected to change in effective stress. Consolidation settlement is often determined using the compressibility parameters, the compression index ( Cc ) and the recompression index (Cr ). However, there is lack of studies on the accuracy of the empirical correlations to predict the recompression index ( Cr ). In addition, no study has been concerned with the development of region-specific correlations to predict the recompression index of fine-grained soils in middle and north of Iraq. Thus, this research has been conducted to fill these gaps by collecting and testing of 350 undisturbed samples, assessing the available empirical correlations and developing of novel region-specific data-driven correlations to predict the recompression index (Cr ) using the evolutionary polynomial regression analysis (EPR-MOGA). The tests include the soil unit weight, specific gravity, water content, Atterberg limits and recompression index. The statistical assessment involved calculating the mean absolute error ( MAE ), root mean square error ( RMSE ), mean ( μ ) , percentage of predictions within error range of ± 30