Numerical Implementation of a Stress-Anisotropy Model for Bearing Capacity Analysis of Circular Footings in Clays Prone to Destructuration

Abstract

Research indicates the presence of in situ structure of soil skeleton in several natural deposits of clay. However, the effect of such in situ structure and its evolution during loading are rarely accounted for in solution of boundary value problems in geomechanics. This paper explores the effects of inherent soil structure and its degradation on bearing capacity of circular footings in structured clays. An advanced constitutive model that accounts for stress-induced anisotropy, soil structure, and their evolutions with loading is implemented within a finite element analysis (FEA) framework. FEA results demonstrate a significant increase in the bearing capacity of structured clay as compared to that in reconstituted clay. Nonetheless, such an enhancement in limit bearing capacity is subdued by destructuration of soil below the footing. A bearing capacity factor accounting for soil destructuration is proposed for inclusion in the limit bearing capacity calculation of circular footings on structured clay. Successful numerical predictions of results from an instrumented field load test on a footing resting on structured clay further substantiates the importance of considering soil destructuration in bearing capacity analysis.