Ultimate bearing capacity of strip and circular foundations using power type yield criterion using the method of stress characteristics

Abstract

For determining the bearing capacity of foundations, the existing investigations have been mainly performed by using a linear yield criterion in shear stress (τ)-normal stress (σn) domain, for instance, the Mohr-Coulomb (MC) and Tresca yield criteria. However, the yield criteria for most granular soils are generally nonlinear with continuously increasing friction angle at decreasing stress level. In the present research, the method of stress characteristics has been employed to compute the ultimate bearing capacity of circular and strip foundations considering a power type (PT) nonlinear yield criterion which depends on three material parameters rather than two in the MC yield criterion. Rigorous solutions have been generated for both rough and smooth footing bases and the results have been expressed in terms of the variation of the bearing capacity factor Nσ with the changes in different material parameters and the overburden pressure. The slip line patterns and the variation of the vertical normal pressure below the footing base have also been examined. Further, the effectiveness of the PT nonlinear yield criterion in determining the bearing capacity of foundations has been discussed. The solutions obtained have been found to compare well with different computational and experimental results reported in literature.