Rigorous design of interactive slab-ground foundation systems on expansive soils remains as a challenge for both practitioners and researchers. Attempts to solve these problems in a generalized way usually involve substantial approximations and have limited success. In this paper, a simple soil behaviour model is adapted into a new finite element formulation. The success of the approach is evaluated by comparing predicted foundation movements with those measured at the Maryland expansive soils field site. In particular, the computed vertical displacements are compared with field measurements. The numerical solutions are generally in good agreement with the observed data.