Evaluating Bearing Capaciy Of Shallow Foundation On Layered Soil Using Finite Element Based Software

Abstract

The Bearing Capacity Of The Foundation Is A Primary Concern In The Field Of Foundation Engineering. Predicting Ultimate Bearing Capacity Of A Footing On Layered Soil Is Very Important As It Is A Requirement For Any Design. The Failure Mechanism Of A Soil Under Footing And The Bearing Capacity Value Mainly Depend On Soil Properties Of Each Layer And The Layer Thickness. It Is Well Established That Safe Bearing Capacity Of Soil Is Affected By Various Factors Such As The Depth Of Ground Water Table (Gwt), Soil Properties, Layering Of Soils, Size And Shape Of The Foundation, Depth Of Foundation Etc. Among Many Other Factors. Hence Most Of The Studies Focused On Homogenous Soils But In Practice Foundations Often Consist Of Layered Soils, It Is Very Important To Consider Layered Soils. In This Thesis A Numerical Model Is Developed Using Plaxis. Finite Element Analysis Is Carried Out Using Mohr-Coulomb Failure Criteria To Represent Three Dimensional Soil Models. For Comparison Purpose The Layered Soil Bearing Capacity Has Been Analyzed By Meyerhof And Hana Method Which Is Classical Approach Method. After That By Comparing Results From Fem And Classical Approach The Analysis Has Been Presented. It?�?S Found That As The Thickness Of Upper Layer To Width Ratio Increase The Bearing Capacity Increase For Stronger Layer Overlying Softer Layer Whereas For Softer Layer Overlying Stronger Layer The Bearing Capacity Decreases. And Also As The Length To Width Ratio Of Footing Increases The Bearing Capacity Of The Soil Decreases. Ground Water Also Significantly Reduces The Bearing Capacity Of Foundation. Spacing Of 1.5 Times The Width Of The Footing Is Also Recommended As Minimum Value.