The Bearing Capacity of a strip Footing on · - Non-Homogeneous (Stratified) Soil

Abstract

Although the interest in analysis of ultimate loads of shallow foundations can be tracked back in literature at least 100 years, when it was initiated by Rankine in 1857, there are however, few theories which predict the behaviour of multi-layer soils. They ranged from averaging the strength parameters, using limit equilibrium considerations, to a more rigorous limit analysis approach. The objective of this research is restricted towards a case of practical importance when a symmetrically loaded strip footing rests on two layers of clays, having different deformation and strength parameters, whether the upper layer is softer or stiffer than the lower one. As it can capture the complexity of boundary conditions and soil non-homogeneity quite accurately, the finite element method is used to calculate the average ultimate bearing capacity of a strip footing rests on a double-clay-layer system. Appropriate constitutive relations and boundary conditions, are used to obtain realistic solutions. Moreover, the effects of the stress state (confining pressure and in-situ stresses) are also considered in the analyses. Results are presented in the form of dimensionless design charts and equations. Moreover, comparisons with experimental results in the literature, are also indicated,