ABSTRACT
The development of a three dimensional soil-structure interaction model based on the finite element method for calculating the structural design parameters (i.e. moments, shears, and deflections) in a slab-on-ground foundation (stiffened or constant thickness) resting on expansive soil is described. The model requires only a statement of the initial soil suction conditions in the supporting expansive soil mass and the changes in the boundary conditions to predict the response of the slab-on-ground foundation to these boundary condition changes. The model can estimate the distorted mound shape by considering soil suction distribution changes in the supporting soil mass and the associated soil volume changes (shrink/heave) with respect to time. The model can consider various combinations of conditions that cause soil moisture and soil volume changes such as climate, moisture barriers, trees, and adjacent ponded water. Examples of the model analysis compared favorably with the observed behavior of experimental slab-on-ground foundations.
