Advanced numerical investigation of Terzaghi's superposition theory

Traditionally the analysis of footings embedded in granular soils has been one of the most difficult finite element simulations to be attempted in geomechanics. This is particularly noticeable by a general lack of published work in foundation analysis using finite elements in the literature. Because of the difficulties involved most of the work performed in this area has concentrated on the use of simple linear elastic, perfectly plastic Mohr–Coulomb constitutive soil models. This paper advances the state-of-the-art by describing the use of a non-linear elastic multi-surface kinematic soil model for the simulation of circular foundations embedded in a particular granular soil. The paper first computes the bearing capacity factors N γ and N q separately, then checks Terzaghi's superposition theory by simulating an embedded foundation (modelled as a surface foundation with an initial surcharge). It is well known that the bearing capacity factor N γ is a function of the foundation width. The paper confirms this, and also shows that the bearing capacity factor N q is actually related to the foundation depth.