Numerical Modelling And Analysis Of Stone Column Beneath A Rigid Footing As A Ground Improvement Technique For Poor Soil Using Finite Element Based Software: In Case Of Bishoftu Town

Abstract

Vibro Stone Columns, Installed Using The Vibro Replacement Technique, Are A Cost-Effective Form Of Ground Improvement For Enhancing The Bearing Capacity And Settlement Characteristics Of Various Soil Types. Over The Last Ix Decades Stone Column Technique Has Become Popular Among Other Ground Improvement Techniques And It Has Been Applied Successfully Around The World. However, In Ethiopia Stone Column Which Offers A Cost-Effective Alternative To Traditional Piled Solutions When Supporting Moderately Loaded Residential, Commercial And Industrial Structures Haven?�?T Applied Yet. This Study Is Intended To Investigate And Clarify The Effectiveness And Applicability Of Stone Column As A Ground Improvement Technique And To Develop Better Understanding On The Application In The Case Of Ethiopia. PLAXIS 3D Foundation V1.1 Is Used For This Research In Conjunction With The Advanced Hardening Soil Model, Which Is Adopted For The Parent Soil And Stone Column. A Set Of Material Parameters And Soil Profile Adopted For This Study Was Collected From Outskirt Of Bishoftu Town Around Eastern Industry Zone And Developed By Correlations Of SPT N Values. The Influence Of Key Design Parameters Such As Area Ratio And Column Confinement, Column Length And Foundation Loading S Upon The Settlement Performance Of Stone Columns Was Investigated Through A Total Of 123 Numerical Analyses Including Preliminary Checks To Ensure Accurate Numerical Analysis. The Modelling Has Shown That The Area Ratio And Column Length Have A Significant Influence On The Settlement Performance Of Stone Columns. In Addition, Foundation Pressure Has Dictated That The Stone Column Improvement Is Efficient At Moderately Loaded Structures. The Settlement Of Treated Footing Has Been Reduced To ??? Of Untreated Settlement At High Area Of Column, While At Medium And Low Area Ratios Of Column The Settlement Has Been Decreased To Half Of Original Untreated One. The Effective Combination Of Column Length To Area Ratio Is That Of Short Column With High Area Ratio And Long Column With Low Area Ratio. The Result From PLAXIS 3D Foundation Code Was Verified With A Numerous Case Studies Performed Abroad. It Was Demonstrated That The Output Obtained From Analysis Fall With In Very Much Acceptable Range, Although The Column Of Low Area Ratio Performed Outskirt From The Extent Of Practicable Case Studies. Based On The Result High And Mean Area Ratio Is Best Suited To Reinforce Rigid Footing, While The Low Area Ratio Was Applicable Efficiently For Wide Area Loading Such As Embankments, Which Can Tolerate Larger Settlement