Bearing Capacity of Square Footing: A Comparative Study Employing Non-associative MC and MCC Model

Abstract

The classical bearing capacity theories adopt a plane-strain framework along with an elastic-perfectly plastic Mohr-Coulomb (MC) constitutive response of soil. It is well known that associative MC model fails to capture the evolution of principal stress and suffers from excessive dilation prediction. A non-associative extension of MC model is often employed to control such excessive dilation response; however, their applicability in prediction of 3D bearing capacity of footings should be explored. Further, the critical state based Modified Cam-Clay (MCC) models are expected to delineate a better stress-strain prediction of soil and it will be interesting to examine the 3D bearing capacity estimates of regular shaped foundations employing these two different models. In this regard, this article addresses the finite-element based bearing capacity estimation of a square footing resting on the surface of a semi-infinite homogeneous soil medium. The footing is represented by linear-elastic element, while the foundation soil has been represented by both non-associative MC and MCC models. Comparison of the load-displacement response of the uniformly loaded footing, obtained from considering the MC and MCC models, clearly delineates the shortcoming of the MC and necessity of adopting MCC behaviour in a 3-dimensional geotechnical problem.