Relationship between compression index and index properties of expansive soils of Akaki Kality sub city

Abstract

Determining The Engineering Properties Of Soil Like Compressibility Parameters Plays A Significant Role In Forecasting Settlement Of Overlaying Structures On The Earth Crust When They Rests On Expansive Soil Mass. One Dimensional Consolidation Test Is One Of The Major Tests That Was Required A Long Time And Extra Cost To Conduct & Used To Know Consolidation Parameters like Compression Index Of Soils. In This Study, Correlations Are Developed To Predict Compression Index (Cc) From Index Parameters So That One Can Be Able To Model Akaki Kality Sub City Soils With Compression Index Using Simple Laboratory Tests. Therefore, Developing Such Correlation Models Are Used To Get Required Parameters With In Short Period Of Time In Addition To Laboratory Cost Minimization. Disturbed Soil Samples From Sixteen Different Locations In Akaki Kality Sub City Were Collected. Laboratory Tests Like Specific Gravity, Grain Size Analysis, Free Swell Index Test, Linear Shrinkage, Atterberg Limit, And One-Dimensional Consolidation Test For A Total Of Sixteen Test Samples Were Conducted. From One Dimensional Consolidation Tests, Compressibility Parameters Like Cc Were Determined. From The Results Of Limited Tests, An Indicative Good Correlation Is Observed Between Cc And OMC, MDD, LL, PL, And PI. The Obtained Correlation equation Of Compression Index Are Cc= 0.06*OMC-1.74, Cc= -2.05*MDD+3, Cc= 0.1*PL 3.07, Cc= 0.04*LL-3.31, Cc= 0.07*PI-3.11, Cc= 0.036*OMC-0.763*MDD-0.01, And Cc= 0.08*LL-0.066*PI-3.207 With R2and RMSE (0.942 & 0.164), (0.924 & 0.018), (0.963 & 0.098), (0.937 & 0.017), (0.823 & 0.085), (0.95 & 0.017), And (0.971 & 0.037) Respectively. Based On Value Of R2 And RMSE Better Correlation Equation Was Obtained From Linear Regression Between Cc & LL. However, A Poor Correlation Is Developed Between Cc And OMC Which Have Higher RMSE Of 0.164 When Compared To The Other Models. The Developed Correlations Will Be Important Inputs In Modeling Akaki Kality Clay Soils With Regression Model Analysis Using Simple Index Tests. In Addition, The Results Of This Study Can Serve As A Basis For Further Study Of Such Correlations On Different Clay Soils In The Country. In This Study, Regression Analysis Was Used To Explore The Significance Of Individual Independent (Index) Soil Properties. Regression Model And Correlation Of Compression Index For Optimum Moisture Content, Maximum Dry Density, Liquid Limit, Plastic Limit, And Plasticity Index Were Obtained From The Linear Regression Analysis. This Correlation Will Be Helpful For Geotechnical Engineers In Developing The Coefficient Of Compression (Cc) Value Of Expansive/Clay Soil From Index Properties. Finally, Based On The General Findings Of The Study, Suitable Recommendations And Best Correlation Model Have Been Forwarded.