Estimation on bearing capacity of shallow foundations in heterogeneous deposits using analytical and numerical methods

In situ soil properties are spatially variable parameters causing soil deposits to be heterogeneous. Heterogeneity consists of two components: (i) A deterministic trend and (ii) The residual component. This paper presents the effect of different components of soil heterogeneity on the ultimate bearing capacity of a vertically loaded shallow foundation resting on clay deposits. The numerical model used in this study is based on finite difference simulations, employing FLAC 5.0. Results of numerical analysis are compared with other simple and analytical solutions. For heterogeneous soil deposits, considering both linear and bi-linear deterministic trends, finite difference tools were found to be able to reect salient features of heterogeneity in bearing capacity estimation. An equivalent homogeneous analysis solution is introduced, in order to allow for heterogeneity, by adopting a representative depth for shear strength measurements. Stochastic variation of shear strength is shown to induce under conservatism by solely relying upon deterministic estimations.