Experimental Study On Dynamic Properties Of Expansive Subgrade Soil Stabilized With Lime

Abstract

Expansive Clay Soils Are Poor Subgrade Materials And Their Engineering Properties Are Primarily Influenced By Intense Moisture Fluctuations. These Soils Exhibit Swelling And Shrinkage Behavior Which Causes Damage To Structures, Particularly Lightweight Buildings And Pavements. Soil Stabilization Using Different Admixtures Is One Of The Most Common Methods Of Treatment For Enhancing The Qualities Of Expansive Soil. Dynamic Characteristics Of Soils Are Important In Designing And Analyzing Geotechnical Structures Subjected To Dynamic Loading. During This Loading, Expansive Soil Loses The Small Shear Strength It Possesses, Resulting In Additional Damage. This Study Investigated The Dynamic Properties Namely Shear Modulus And Damping Ratio Of The Untreated And Lime-Treated Expansive Subgrade Soils For Different Strain Amplitudes Ranging From 0.01 To 1%. The Strain Amplitude, Confining Pressure, Cycle Number, And The Effect Of Lime Treatment Were The Parameters Considered In This Study. The Study Is Carried Out On Expansive Subgrade Soil Samples Collected From Addis Ababa, Summit- Figa Road Project. The Experimental Study First Performed Atterberg Limits, Free Swell, Compaction, Unconfined Compressive Strength (Ucs), And California Bearing Ratio (Cbr) Test On The Mixtures Prepared By Adding Different Percentages Of Lime (0,3,6, And 9%). Laboratory Cyclic Simple Shear Tests Were Then Performed To Determine Dynamic Properties On The Natural Soil Samples And Remolded Soil Samples Treated With Lime Prepared By Compaction. Test Results Show That The Plasticity Characteristics And The Swelling Potential Of The Expansive Clayey Soil Decrease With Increased Lime Content And Ucs Of Soil Increases Up To 6% Addition Of Lime By Dry Weight Of The Soil. It Was Found That For Both Lime-Treated And Untreated Soil Samples The Dynamic Shear Modulus Decreases As The Strain Rate Increases While Increasing With The Number Of Cycles And Confining Pressure. Conversely, The Damping Ratio Value Increases As The Shear Strain Rate Increases Whereas, It Decreases As The Number Of Cycles And Confining Pressure Increase. Furthermore, Results Indicate That Treated Soil Has A Higher Shear Modulus And Lower Damping Ratio Than Untreated Soil. Generally, The Study Shows The Use Of Lime To Stabilize Expansive Subgrade Soil Under Both Static And Dynamic Loading Is Effective In Increasing The Stiffness Of The Soil And Reducing Deformation.