Abstract:
This study aims to develop empirical correlations for the compression index (Cc) and the coefficient
of consolidation (Cv) with the liquid limit (LL) for soils from various locations in Pakistan. This
research addresses the gap by offering a simpler, cost-effective method to estimate Cc and Cv based
on LL, thereby reducing the need for extensive laboratory testing. Soil samples were collected from
100 different sites and subjected to comprehensive laboratory testing, including sieve analysis,
hydrometer analysis, specific gravity determination, Atterberg limits, and consolidation tests using an
Oedometer apparatus. A critical comparison was made between the liquid limits obtained from soils
passing through sieve #40 and sieve #200, highlighting the impact of fine sand inclusion on LL
values. Initially, 40 correlations were developed by exploring various soil index properties; however,
only 4 correlations were retained due to the minimal impact of other parameters compared to the
liquid limit on the compression index and coefficient of consolidation. Priliminary attempts to
correlate Cc and Cv with multiple soil parameters through a multilinear regression model indicated
high p-values, prompting a focus on LL as the sole predictor. The simplified model demonstrated
statistical significance, with low p-values affirming the robustness of the correlations. To validate
these findings, additional soil samples from 50 locations were analyzed, and the resultant percentage
error for both Cc and Cv was found to be less than 1%, ensuring the reliability of the developed
correlations. By comparing the results with past research, it was observed that previous models often
overestimated or underestimated Cc and Cv values. This research offers more accurate and region
specific correlations, enhancing the understanding of soil compressibility characteristics in Pakistan
